Note: Descriptions are shown in the official language in which they were submitted.
1065039
BAC~GROUND OF THE INVENTION
This invention pertains to a method and apparatus for
facilitating the operation of rallway trains. More specifi-
cally, the invention comprises a novel method and apparatus
for dynamically monitoring car presence upon an underlying
track profile and calculating car coupler forces throughout
the extent of a train to provide an informational base for
optimizing operation of the train over a predetermined route
of travel. -
; In the infant stages of railroad technology locomotive
pulling capabilities limited the length of trains to a few
cars, such as 10 to 20, with corresponding relatively low
maximum speeds on the order of 20 to 30 miles an hour. Dur-
ing this era even novice locomotive enginemen had little dif-
ficulty in controlling a train. In this connection the entire
train could be effectively monitored merely by rearward obser-
vation from the locomotive cab. Efficiency around curves and
on grades, as tempered by safe operational procedure, could
be quickly acquired by a "seat of the pants" feel since the
entire train essentially acted as a single unit wherein grade
and curvature effects produced upon the locomotive were in
essence concomitantly applied to the entire, relatively short,
train.
Over the years, however, advances in railway engineering, ~-
such as the development of diesel electric locomotives utilized
in multiple unit consists have advanced pulling capacities
several magnitudes with respect to the early wood burning
steam drive systems. This increase in pulling capacity has
permitted marshaling longer and longer trains with higher and
,
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higher tonnage. It is no longer unco~ on to encounter train
consists of one hundred and fifty to two hundred cars stretch-
ing over a length of one, one and one-half to two miles.
In addition to the foregoing increases in train length
and tonnage, a desire for increased operating efficiency has
pushed operating speeds upward.
Unfortunately, with the foregoing noted increase in
train lengths, tonnage and operating speeds, locomotive opera-
tional control equipment has remained substantially unchanged.
In this connection enginemen still are operating trains to a
large extent based upon a "seat of the pants" feel.
While experience and feel for train operational forces
have remained the standard of the industry, efficiency can
only be acquired after many years of experience over a well
known run. In this regard it will readily be appreciated that
human sensory perceptions as to grades, curves, etc. within a
locomotive have little relevance to the end of a train one
or two miles away. Further, gentle grades are often imper-
ceptible to an engineman, although with long train lengths J
high tonnage and elevated speeds, significant coupling forces
may be produced between adjacent cars even on gentle grades. - -
It would therefore be highly desirable to provide a
method and apparatus which would present a locomotive engineer
or engineman with an accurate appreciation of track profile
and relative train presence throughout the extent of the train,
as the train proceeds along a predetermined route of travel.
With this basic information available, it should be possible
for even a relatively noviceengineman, totally unfamiliar with
the terrain of a particular run, to efficiently utilize grades
to maintain optimum speeds and slack conditions as the train -
~proceeds along the route of travel.
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The above noted control difficulties are greatly accen-
tuated when dynamic "train action" forces are considered. In
this regard, train action or slack action events may be de-
fined as a phenomenon which occurs as a consequence of the
existence of slack in couplings between moving railway units.
Such slack enables theunits, during system travel, to undergo
relative movement. Thus, train action denotes the equaliza-
tion of speed of adjacent units which have undergone relative
movement. A train action event is termed a "run-out" where
adjacent units are moving apart. Where adjacent units are
converging, the train action event is termed a "run-in."
There are numerous undesirable aspects associated with
train action phenomena. During train action events shock
forces are transmitted through the coupling units. These
shock forces are propagated in a more or less wave form
throughout the train. Such train action induced shocks are
frequently severe enough to both damage goods carried by the
trains and cause injury to train crewmen. Indeed train action
induced forces may be severe enough to induce car partings and
in some circumstances even derailment.
In the recent past, significant advances have been
achieved in terms of obviating or minimizing the severity of
slack action forces by the development of hydraulic cushioning
units operable to be connected in series with car coupler shanks.
Examples of such hydraulic cushioning units are disclosed in
United States Seay patent No. 3,301,410, United States Blake
patent No. 3,463,328, United States Seay patent No. 3,589,527,
and United States Stephenson patent No. 3,589,528, all assigned
to the assignee of the subject invention.
., .,.. ~ . ': :.
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Notwithstanding, however, singular advances provided
the railway industry by the developmen~ of hydraulic cushion-
ing units, room for significant improvement remains in dealing
with train action events.
In this latter connection it would be highly desirable -
to provide a method and apparatus for dynamically determining
coupling forces throughout a train of widely varying consist
as the train proceeds along a predetermined route of travel.
With such force profile data an engineman may anticipate train
action events so that appropriate preventive locomotive con-
trol may be initiated through appropriate application of the
locomotive throttle, locomotive dynamic brakes, locomotive
independent air brakes and/or automatic train brakes.
OBJECTS AND BRIEF SUMMARY OF THE INVENTION
Objects of the Invention
.
It is therefore a general object of the invention to
provide a novel method and apparatus for facilitating control
of a railway train which will obviate or minimize problems
of the type previously described.
It is a further object of the invention to provide a
novel method and apparatus for facilitating efficient opera-
tion of a railway train.
It is still a further object of the invention to pro-
vide a novel method and apparatus wherein a trAin may be
efficiently operated over a widely varying terrain.
It is yet a further object of the invention to provide
a novel method and apparatus wherein a relatively inexperi-
enced engineman may effectively handle long trains even with
widely varying consists.
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`` 1~65039
It is yet another object of the invention to provide a
novel method and apparatus wherein a locomotive engineman may
improve performance of the train with reduced fuel consumption
by optimizing the utilization of grades in achieving speed
maintenance of the train.
It is another object of the invention to provide a novel
method and apparatus wherein train operational indicia may be
disclosed in substantial real time to an engineman within a
locomotive cab whereby operation of the train may be effec-
tively optimi~ed.
It is another object of the invention to provide a novelmethod and apparatus for facilitating safe and reliable opera-
tion of a train wherein the tendency for train partings and
derailments are effectively minimized.
Itis still yet anotherobject ofthe invention to providea
novel method and apparatus wherein coupling forces throughout
the length of the train may be dynamically calculated as the
train proceeds along a predetermined route of travel.
It is yet still another object of the lnvention to pro-
vide a novel method and apparatus for dynamically displaying
to an engineman within a locomotive cab real time train pre-
sence upon an underlying track profile and a coupling force
profile throughout the extent of a train as the train proceeds
along a predetermined route of travel.
It is a further object of the invention to provide a
n~vel method and apparatus for facilitating effective opera-
tion of a train which is relatively inexpensive in initial
installation and highly rugged and practical in operation.
It is yet a further object of the invention to provide -
a novel method and apparatus for recording and storing opera-
tional parameters of a train as the train proceeds along a
predetermined route of travel.
Brief Summar~
: .- - , ' . ' , : . ,
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.
.
5039
A method for facili-tating control of a train according
to a preferred embodiment of the invention, intended to accom-
plish at least some of the foregoing objects, includes d~ter-
mining car consist information throughout the length of the
train such as, for example, length of each car, average weight
per axle for each car, total number of axles for each car and
average cross-sectional area for each car. Track profile in-
formation is also determined, such as track grade and curva-
ture for a predetermined route of travel. The velocity of the
train is dynamically determined as it proceeds along the pre-
determined~route of travel by measuring the velocity of the
locomotive. Coupling forces between the locomotive and the
first car of the plurality of articulated cars are dynamically
determined by (1) direct measurement at the locomotive cou-
pling shank; (2) measuring the main traction motor current
and calculating locomotive coupling force; or (3) measuring
main generator current and main generator voltage and calcu-
lating locomotive coupling force. The car consist informa-
tion, track profile information, locomotive velocity and loco-
motive coupling force are input into a general purpose digital
computer which dynamically calculates the coupling forces
between each car throughout the extent of the train. This
coupling force information along with the track profile and
train presence is then projected upon an electronic display ~-
screen within the cab of the locomotive to facilitate opera-
tion of the train by an engineman.
The apparatus according to a preferred embodiment of the
invention includes a means for storing car consist information
and track profile information such as a magnetic or paper tape
storage device. A means is provided for determining velocity
of the locomotive such as measuring wheel rotation and correct-
ing for wheel slip and creep, to compute the velocity of the
.
,,: ; '' ''
65039
train. Means is also provided for dynamically determining
locomotive coupling force as the train proceeds along the pre-
determined route of travel. Such means may comprise: (1) a
direct dynamometer measurement of coupling force on the loco-
motive coupler shank; (2) means for measuring traction motor
current and calculating locomotive coupling force; or (3)
means for measuring main generator current and main generator
voltage and calculating coupler force. A general purpose
digital computer is provided to receive input of car consist
information, track profile information, locomotive velocity,
and locomotive coupling force for calculating coupling force
throughout the extent of the train. An electronic display
screen is mounted within the cab of the locomotive and receives
signals from the computer for providing traces of track pro-
file, train presence upon the track profile, car coupler force
distribution and other train information and operational in-
structions as desired.
.
THE DRAWINGS ~ ;
Further objects and advantages of the invention will
become apparent from the following detailed description taken
in conjunction with the accompanying drawings, wherein:
FIGURE 1 is a schematic plan view of a train including
a locomotive set and a plurality of articulated cars coupled
thereto composed of a widely varying consist;
FIGURE 2 is a side elevational view of the train depicted
in FIGURE 1 and particularly discloses the train passing
through a track grade depression wherein ascending cars are ~ -
stretched and in tension while descending cars are bunched and
ln compresslon;
.
65C~39
FIGUR~ 3 is a side elevational view of the train
depicted in FIGURES 1 and 2 as the train is proceeding over
a knoll wherein descending cars are stretched and in ~ension
,
:~ and ascending cars are in like manner stretched and in tension;
: FIGURE 4 is a side elevational view of a diesel electric
. .
locomotive set or pair; ~ -
. FIGURE 5 is a cross-sectional view taken along section
line 5-5 in FIGURE 4 and discloses a plan view of the interior
of the lead diesel electric locomotive depicted in FIGURE 4;
FIGURE 6 is a cross-sectional view taken along section
. line 6-6 in FIGURE 4 and discloses an elevational, forward-
looking, interior view of the cab of the diesel electric
locomotive depicted in FIGURE 4;
FIGURE 7 is an illustrative plan view of a typical dis-
play according to a preferred embodiment of the subject in-
vention wherein various indicia are depicted including a ~ -
track grade profile and mile post indicators superimposed
~ upon the track grade profile, a depiction of a train pro-
.` ceeding along the track grade profile, a track curve profile
coextensive with the track grade profile, a calculated coupler
force distribution between each of the plurality of articu-
`: lated cars of the train, town locations upon the track grade
: profile, speed limit zones upon the track grade profile, and
information and instructions for operating the train; -
: FIGURE 8 depicts a train mathematical model indicating
coupler forces and resistance forces of individual cars of
the train;
FIGURE 9 is a schematic block diagram according to a
preferred embodiment of the invention wherein dynamically
measured coupler forces between the locomotive and the next
adjacent car of the train are utilized to compute forces
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10~5039
between each car throughou. the extent of the train and pro-
ject the computed forces upon a cathode ray tube display
within the cab of the locomotive;
FIGURE 10 is a block diagram accordiny to a first alter-
nate preferred embodiment of the invention wherein locomotive
traction motor current is utilized to dynamically compute
forces between the locomotive and the next adjacent car of
the train which in turn are utilized to compute individual
coupling forces throughout the extent of the train and project
the computed coupling forces upon a cathode ray tube display
positioned within the cab of the locomotive;
FIGURE 11 is a second alternate preferred embodiment of
the invention wherein locomotive main generator current and
main generator voltage are utilized to calculate locomotive
coupling forces which in turn are utilized to compute indivi-
dua~ coupling forces between each of the articulated cars
throughout the extent of the train and project the computed
coupling forces upon a cathode ray tube display positioned
within the cab of the locomotive;
FIGURES 12 A-G comprise logic flow charts for each of
the preferred embodiments of the invention for dynamically .
computing coupling forces between each car throughout the
extent of the train and displaying the computed forces upon
a cathode ray tube pcsitioned within the cab of the loco-
motive; and
FIGURES 13-29 disclose simplified cathode ray tube
displays of a train proceeding along a track profile between
mile posts 296 and 299 and computed car coupling force dis-
tributions throughout the extent of the train as ~he train
proceeds along the predetermined route of travel.
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1065039
DETAILED DESCRIPTION
.
Context of the Invention
.. .. . .
Before discussing in detail preferred embodiments of
the subjeet invention a brief background exposition of train
aetion phenomena may be useful.
In this connection FIGURES 1 and 2 disclose plan and
side elevational views respectively of a train 100 operably
positioned upon an underlying roadbed and-railway track 102.
The horizontal profile discloses a general curvature or bend
in the roadway. The track grade is depicted in FIGURE 2 and
eomprises a slight depression or valley wherein a zone of
maximum turning 104 in FIGURE 1 generally coincides with a
lowermost portion 106 of the grade profile.
The train is eomposed of first and seeond diesel elee-
trie loeomotives 108 and 110 eoupled in tandem into an opera-
tive pair for pulling a string of artieulated railway ears ~-
in the general direction of arrow 112. In some instances mid- `
train locomotive units (not shown) may advantageously be
utilized; however, for ease of illustration only forward or
lead units are shown herein. The car consist of a typical
train as depicted in FIGURES 1 and 2 includes randomly posi-
tioned cars of widely varying size, weight (both loaded and
empty), and function. More specifically the train consist
may inelude gondola ears 114, 116 and 118, box ears 120 and
122, tank ears 124 and 126, a piggyback flat ear 128, general
purpose flat ears 130, 132, 134, 136 and 138, and hopper ears
140 and 142. It will be appreeiated that the foregoing
illustrative eonsist is entirely random and the lengths,
weights, and eross-sectional area, and in some instances the
number of axles, may vary from car to ear. -
--11--
1065039
The cars are interconnected with conventional coupling
units 144 so as to produce an articulated train coupled be-
hind the pulling locomotives 108 and 110.
The coupling units 144 are typically connected to the
car underframe sill structure through draft mechanisms.
While friction and rubber draft gears having operative
strokes of 2 to 4 inches are widely utilizedj application
of hydraulic cushioning units of the type previously noted
is wide spread throughout the industry. These hydraulic
cushioning units typically vary in stroke from 7 to 15 inches ~
for each coupler shank. Thus in a composite coupling junction -
hydraulic draft units may provide 30 inches of cushioned tra-
vel from complete "run-out" to complete "run-in." Still
further dimensional clearances within the coupling structures
~ provides a few inches of play at each coupling junction.
; Accordingly and as illustrated particulary in FIGURES 1
and 2, when cars of the train are ascending a grade such as
the first five cars of the train 100, the couplers of ascend-
ing cars are typically placed in tension and the spacing
between cars may be "run-out" or the draft gears will be
fully extended, as illustrated by spacing lines 150, 152, 154,
156 and 158. As cars are descending a grade, however, there
will be a tendency for the cars to close relative to one
another and the cars will be "run-in" or the draft gears will
be fully closed, as shown at 162, 164, 166, 168, 170, 172,
174, 176.
A transition zone exists where the cars may not be com-
pletely run-in or run-out. Such intermediate spacing is illu-
strated at 178 in FIGURE 1 wherein the hydraulic cushioning
units are capable of movement in either direction.
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1065039
Run-in phenomena as previously noted are extremely
undesirable train action events which may generate high com-
pressive forces, components of which may be suficient to
lift or tend to lift a car at the lowermost portion of the
tract and thus present a potential derailment situation.
This difficulty is greatly accentuated when a curve is en-
countered at a low portion of the tract profile. In this
connection a component of the compressive force will tend to
push the cars in zone 104 such that the wheel flanges will
ride over the rails and derail the train. Furthermore, once
a car is completely run-in it in essencebecomesa solid mass
with the next adjacent car. Accordingly, if ten or twenty
cars are run-in the coupler force of a solid mass of steel
ten or twenty cars long is input to the lead coupling. As a
consequence of these blocks of cars acting as a single moving
mass still higher forces can be developed greatly increasing
the probability that a derailment might occur.
Referring now specifically to FIGURE 3 a different type
of undesirable train action is illustrated. In this connection
the entire train 100 is run-out with maximum spacing 180, 182,
184, 186, 188V 190, 192, 194, 196, 198, 200, 202 and 204 at
each coupling unit. With the entire train stretched and the
locomotive proceeding on a downgrade, pulling force by the
locomotive may generate tremendous tensile loads at the apex
zone 206 of the track profile. Accordingly, as cars pass over
this zone there is a distinct possibility of a train parting
because of a broken knuckle in the coupler, sheared coupler
pin or the like.
Train partings, while not as disastrous as derailments,
are highly unacceptable to economic railroad management. In
this connection, the frontportion o the train must be backea
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1065039
up in order to repair the coupling and reestablish a con-
n ection. This work may tie up a track for extended periods.
Since most lines are still multidirectional on one track,
traffic will be tied up in both directions while the repairs ~
are made, thus necessitating rescheduling, etc. -
From the foregoing it will be appreciated that it would
be highly desirable to be able to dynamically monitor car
coupling forces and thus provide an informational base to
minimize potential derailment and parting situations.
System Components
Referring now particularly to FIGURES 4, 5 and 6 of
the drawings there will be seen views of a typical diesel
electric locomotive set and interior sectional views of a
locomotive cab employing components of the subject invention.
More particularly, a train consisting of 75 to 150 or
more cars is typically pulled by two to five diesel electric
locomotives 210 and 212 operating in tandem. Locomotive 210
is representative of locomoti~e 212 and is designed with a
forward cab compartment 214, a main generator 216 and a diesel
.
engine 218 operable to drive the generator. The generator
supplies electricity to drive a series of six traction motors
220 connected through gearing to the wheels ~f the locomotive.
Looking within the cab 214, note FIGURES 5 and 6, there
will be seen an engineman's sliding seat 222 and one or more
auxiliary seats 224 for additional cab personnel. The engine-
man's chair is located adjacent to a control console 226. The
control console includes a conventional eight notch throttl~e
228, train line air brake valve 230 and an independent loco-
motive air brake valve 232.
Positioned adjacent the control console 226 are com-
ponents of the invention including an input keyboard located
.:' .
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1~5~3~
generally at 23~, a ceiling suspendea housing 236 which is
designed to carry a general purpose digital computer at 238,
a primary mass storage device at 240 and a secondary mass
storage device at 242. Finally, a cathode ray tube display
module is mounted upon the forward wall of the cab as at 244.
The operative interrelationships of the input keyboard,
the computer, the primary and secondary mass storage devices
and the display module will be more fully discussed herein-
after with reference to block diagrams and logic flow charts
of FIGURES 9-12. Briefly, however, these components function
to dynamically display train parameters such as vertical and
horizontal track profiles, train presence relative to the
profiles, coupling forces throughout the train, etc. to an
engineman seated in chair 222 as the train proceeds along a
predetermined route of travel.
Electronic Display Screen
Referring now to FIGURE 7, there is shown an electronic
display device 300 in accordance with a pre~erred embodiment
of the invention. The electronic display device 300 is of
a conventional design and may be, for example, a cathode ray
tube (CRT) which may be scanned in any suitable conventional
manner such as through the use of a raster scanning and inten-
sity modulating technique or by oscilloscope type scanning
techniques.
An initial track profile trace 302 is projected upon
the screen and represents vertical grades of an undulating
track along a predetermined route of travel~. The grade pro-
file 302 is intercepted at regular intervals 304 by vertical
traces headed by sequential numeric representations 296-301
indicating mileposts along the predetermined route of travel.
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1065039
A train display 306 is projected upon the cathode ray screen
in a posture overlyiny the track profile and represents the
length and position or presence of the train with respect
to the track profile. Still further, town locations 308,
speed limit zones 310, etc. may be superimposed upon the
track profile 302.
In addition to the foregoing vertical track profile,
horizontal curve profile information is depicted by trace
312 wherein curves are dotted as at 314 and 316 with a nume~
ical degree of curvature identified as 2 (degree) CR and
50' (minutes) CR, respectively.
Underlying the train profile 306 is a car coupler force
profile 318. A zero force ordinate 320 is projected co-
extensive with the coupler force profile. As illustrated
in FIGURE 7, therefore, the coupler forces between adjacent
cars throughout the entire train are positive values and the
entire train is stretched. The initial value as at 322
represents the coupling force between the locomotive and the
next adjacent car while the final value at 324 represents
the force of;the last car which must necessarily be zero.
In some instances, it may be desirable to represent a
second, hypothetical car coupler force profile 326 which
depicts a calculated force profile throughout the extent
of the train in the event a hypothetical locomotive coupling
force were imposed upon the first car as at 328 instead of
the actual coupling force 322. This hypothetical force pro-
file may be useful in depicting what pulling force is required
in order to maintain the coupling force profile throughout
the extent of the train as a positive value or above the
ordinate.
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~065039
Additionally, train operational information and in-
structions may be alphanumerically displayed upon the screen
300. In this connection, operational information sueh as
eurrent train speed 330 and calculated train aeceleration
332 after a certain distance is traversed with a particular
throttle setting and track profile may be useful to an
engineman in the operation of the train. Further instruc-
tions 334, such as proper throttle notch setting to minimize
train aetion events, eritieal minimum speeds necessary to
avoid harmonic ear oscillations, etc. may be displayed to
an engineman.
The foregoiny indicia depicted in FIGURE 7 are not
meant to be exhaustive and one skilled in the art will be
able to further supplement, this visual display to a loco-
motive engineer in order to effectuate a more efficient and
reliable operation of the train.
~ Mathematical Model
'~ In accordance with a preferred embodiment of the sub-
jeet invention it has been determined that a ear eoupler
foree distribution profile may be mathematically ealeulated
throughout a train with sufficient aceuraey to be of sub-
stantial utility in anticipating and thus minimizing train
aetion events. In order to fully appreciate the development
of mathematical approximations for eoupling force between
eaeh ear a model may be useful, such as illustrated in
FIGURE 8, wherein a lead loeomotive set 400 is eoupled to
an artieulated string of cars 402. The ears may be ref-
ereneed in sequential numeric order taking the eaboose 404
as ear l and proceeding toward the loeomotive set 400.
The eaboose 404 is not coupled to a further ear thus
the eoupling force at the end of the eaboose F~ is equal to
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zero. The coupling force at the lead end of the caboose or
first car is equal to a summation of the resistance forces
of the caboose to forward motion. These forces may be
approximated by a rolling resistance factor RR, a braking
resistance factor RB and an acceleration resistance RA.
Rolling resistance RR includes such factors as (a)
rolling friction between wheel and rail; (b) axle bearing
friction; (c) flange friction which varies with speed; (d)
air resistance; (e) track grade resistance and (f) track
curvature resistance.
Braking resistance RB is a factor applicable when
individual brake shoes mounted upon each car are applied.
Under many running conditions the individual car brake shoes
will not be applied and this factor will accordingly be zero.
Acceleration resistance RA is a factor which is required
to produce accelerated translation of the car, and accelerated
rotation of the car wheels about their axle centers.
In eguation form such forces for the caboose or first
car may be represented as follows:
RBAl RRl + RBl + RAl-
In a similar vein the coupling force at the lead end of the
second car 406 is equal to a summation of the resistance
forces of the caboose and the resistance forces of the second
car to forward motion. In equation form such forces may be ~
represented as follows: ~ -
FRBA2 = (RRl + RBl + RAl)+(RR2 B2 A2 ~
= (RRl + RR2) + (RBl + RB2) + (RAl + RA2) .
Generalizing for an nth car the equation becomes:
n n n .-
FRBA = ~ RRi ~ ~ RBi + ~ RAi-
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106503~9
A numeric factor for rolling resistance FR for an
nth car may be calculated from a modified Davis train re-
sistance formula as follows:
Rn ~1.3 + W + Cvn V + CDnAnV ) Wn Nn (2)
W N
n n
+20GW N + 0.8C W N
n n n n
-~ wherein:
RRn = rolling resistance of the nth car, pounds;
Wn = average weight per axle of the nth car, tons;
C~n = coefficient of rolling resistance of the nth car,
typically 0.030 to 0.045~
V = speed, assumed to be the same throughout the
length of the train, mph;
CDn = wind resistance drag coefficient of the nth car,
typically 0.0003 to 0.003;
An = cross-sectional area of the front of the nth
carl sq. ft.; -
Nn = total number of axles of the nth car; and
G = ascent or descent in feet-in-one-hundred or per-
cent grade beneath the nth car; and -~
C - track curvature in degrees beneath the nth car.
Using such parameters as the length of each car together
with the location of the train on the track, the grade and
curvature for the track under each car can be determined
from recorded track profile data over a predetermined route
of travel.
The braking resistance factor RB may be estimated for
those circumstances when the independent train brake shoes
are in application. The braking force on the nth car may
be numerically determined by:
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1065t~39
n n (3)
wher~in:
~n = train braking resistance of the nth car, pounds;
PCn = brake cylinder pressure of the nth car, psi;
Ac = brake cylinder piston area of the nth car, sq.in,;
L = brake lever mechanical advantage of the nth car;
e = brake rigging efficiency of the nth car; and
f = brake shoe to wheel coefficient of friction of
the n car.
It should be noted that the factors Ac, L and e can be
prespecified as an average parameter for each car. The co-
efficient of friction is a function of car speed, type of
brake shoe and wheel temperature. The coefficient of friction
can be determined using empirical relationships available
from manufacturers of car brake equipment.
The brake cylinder pressure PCn is a function of the
j relatively recent history of the train line air pressure which
is measured at the lead locQmotive and used as required to
predict the state of application of the train brakes. Empir-
ical relationships describing the buildup of pressure at each
brake cylinder have also been established by manufacturers
of car brake equipment.
In determining the acceleration resistance an assumption
is made that the entire train accelerates equally. With this
initial assumption, the pulling force for the entire train ;
between the locomotive set 400 and the next ad~acent car less
the total rolling and train braking resistance of the train is
equal to the total effective mass of the train times the ac-
celeration. In equation form this relationship may be indi-
cated as follows:
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total total . total
Floco ~ ~ ~ Ri 1_1 RBi) = ( ~ Mei) a or
total total
a = Floco ~ ( i=l R ~1 R
~ M .
i=l el
A numeric acceleration term RA for an nth car may be deter-
mined as follows:
RAn = a(Men effective)
total total
( loco ( i~l i=l Bi en
total ~ ~:
.
wherein:
Fl~Co = coupling force between the locomotive and
the adjacent car of the train
RR = the rolling resistance of each car as deter-
mined by equation (2);
RB = the train braking resistance of each car as
determined by equation (3); :
Wn = average weight per axle of the nth car;
Nn = total number of axles of the nth car; and
Men = the effective mass of the nth car which
includes a factor for translation accelera~
tion and a factor for wheel rotation accel-
eration;
= 91.05 WnNn + 36-36Nn.
From the foregoing the coupling force between each car
FRBAn may be computed from equation (1). While the fore-
going equations have been developed on the basis of lead
locomotives only, those skilled in the art will be able to
.
--.
-21~
.
.
. - , . ~ ~ 1
- ~65039
alter these equations to account for one or more midtrain
locomotive units.
System Description
Onepreferred system for dynamically analyzing the opera-
tion of a train and facilitating control of the train in re-
sponse to the analysis is illustrated in FIGURE 9. More
specifically, a general purpose digital computer 500 (shown
at 238 in FIGURE 5) is coupled through conventional computer
interfaces 502 with various data input and output devices
described hereinafter.
An input keyboard and various control switches 504
(shown at 234 in FIGURE 6) provide communication between the
train engineman and the dic3ital computer 500 through the
computer interfaces 502. The keyboard may be, for example,
a conventional push button telephone keyboard and the control
switches may permit the engineman to select various system
options and perform control functions in a conventional
manner.
In addition to the date storage capacity provided by
the computer 500, primary and secondary mass storage devices
506 and 508 (shown at 240 and 242 in FIGURE 5) may communicate
with the digital computer 500 through a conventional controller
and formatter 510 and the computer interfaces 502. The mass
storage devices 506 and 508 may be, for example, magnetic or
paper tape storage units and may be used to store track pro-
file and consist data obtained prior to a given run and record
and store, for subsequent evaluation, selected operational
data of the train as it proceeds along a route of travel. -
The controller and formatter 510 functions to control
the transfer of data between the computer 500 and the storage `
devices 506 and 508 in response to commands from the computer
-22- -
- 10~;5C~39
500. The controller and formatter 510 also insures proper
formatting of the data transferred Erom the computer 500
and the storage devices 506 and 508. The controller and
formatter 510 may be any suitable conventional device capable
of performing functions in conjunction with the particular
computer and the storage devices being employed. Such units
are typically available from either the computer manufacturer
and/or the supplier of the storage devices.
In the embodiment of the invention illustrated in FIGURE
9, the previously discussed (note Mathematical Model section)
locomotive pulling or coupling force (FloCo) is preferably
determined in response to a direct measurement of force
exerted on the coupler shank between the locomotive and the
next adjacent car. To provide this measured force, a con-
ventional dynamometer coupler 512 is mounted upon the coupler
shank to provide an output signal related to the locomotive
consist pulling or braking force exerted upon the cars of
the traln. The output signal from the dynamometer coupler
512 is fed into a suitable analog signal conditioner 514
for amplifying and filtering. The amplified and filtered
output signal from the analog signal conditioner 514 is then
applied to a suitable conventional selective signal scanning
device such as a multiplexer 516.
Sim-~larly, the train line air pressure, used in deter-
mining independent car braking resistance (RB), may be
sensed by a suitable conventional pressure transducer 518
and supplied through another analog signal conditioner 520
to the multiplexer 516.
For record keeping purposes, locomotive independent
air brake pressure may be sensed by a suitable conventional
, . . . . . . .. .
1~5039
pressure transducer 522 and supplied to the multiplexer 516
through an analog signal conditioner 524.
The multiplexer 516 may be controlled in any suitable
conventional manner by the computer 500 to supply the condi-
tioned output signals from the dynamometer coupler 512 and
the pressure transducers 518 and 522 to the digital computer
500 as required during the operations performed by the com-
puter. For example, each of the signals may be continuously
supplied to the multiplexer 516. When a particular signal is
required in a computation, the computer 500 may address the
appropriate input signal and gate that signal through the
multiplexe~ 516.Since the force and pressure related signals
are analog signals in the illustrated embodiment, an analog
to digital converter 526 is provided to convert the analog
signals to a digital format compatible with the digltal com-
puter 500
Other quantities utilized in the calculation of force
distribution and further optional or additional functions
performed by the digital computer 500 may be supplied in any
suitable conventional manner. For example, information as
to the train velocity may be supplied from a conventional
pulse generator 528 driven by wheel rotation of the loco- ~
motive. The rate of pulse input from the pulse generator 528 -
is directly indicative of train velocity and may be appro-
priately conditioned by a suitable digital signal conditioner
530 and made available to the computer 500 for use in the
calculations as required. The digital signal conditioner
530 may be any suitable conventional circuit for isolating
any undesirable variables contained in the pulse generator
signal from the computer 500. For example, the pulse gen-
erator 528 may be a conventional digital tachometer which
1065~39
generates pulses having varyinc; c~npli~udes. Since the com-
puter 500 requires binary signals having a relati.vely constant,
low voltage level (e.g., 5 volts d.c.) the signal conditioner
530 may eliminate the variations in d.c. level of the pulses
from the pulse generator 528 through a suitable coupling
technique such as through the use of light emitting diodes
which couple only the binary information of the pulses to the
computer 500.
Other signals indicative of quantities such as wheel
slip and wheel creep are used to correct veloclty and loca-
tion calculations, and various train line functions used, for
example, to record throttle operation by an engineman may
also be provided through similar digital signal conditioners
generally indicated at 532.
In a preferred embodiment of the invention, the dis- :
tribution of car coupler forces in the train is preferably
displayed through an electronic scanning technique. Accord-
ingly, data definin~ the inform~tion to be displayed is
: applied through a conventional display controller 534 to an
electronic display 536 such as a cathode ray tube (CRT) as
previously mentioned in connection with FIGURES 5-7.
The display 536 may be an oscilloscope display wherein
the vertical and horizontal positions of an electron beam
are controlled to generate the display or alternatively a
raster scan type of display wherein the intensity of a
regularly scanned beam is controlled to generate the display.
Assuming that an oscilloscope type of display is employed,
the display controller 53 may be provided with X and Y
coordinates of discrete points which together define the
desired display. From these discrete points, the display
controller may generate suitab-e horizontal and vertical
-25-
- - . . . . .
: ., - . , . : ,; .; . .
1~65039
deflection signals of an analog nature to deflect the
el~ctron be~m of the display device along a path defining
the desired display. ~dditionally, blank:ing signals may be
generated to blank the beam at appropriate X and Y values
along a scan line.
If a raster scan display device is utilized, the X,
Y and Z intensity values of discrete points defining the
desired display may be stored by the display controller and
utilized to vary the intensity of the scanned electron beam
in coordination with the vertical and horizontal scanning
signals of the display device. For example, all of the
stored points may be stored in order as to their X positions
(i.e., the order of raster line on the display device), and
for each raster line having more than one point thereon,
may be ordered in accordance with the Y or horizontal value
along that raster line. When the beam of the display device
reaches a particular X, Y value corresponding to a point to
be displayed the display controll2r may then modulat2 the
intensity of the beam in accordance with the stored ~ value ,
of that point. Such display techniques are conventional and
therefore will not be described in further detail.
FIGURE 10 illustrates another embodiment of the present
invention wherein locomotive pulling force FloCo is calcu-
lated as a function of the locomotive traction motor current
as will be described more fully hereinafter. In the embodi-
ment of FIGURE 10, traction motor current may be monitored
in a suitable conventional manner by shunting a portion of
the traction motor current through shunt 538. The signal
related to traction motor current may be provided from the ~:
shunt 538 through a suitable analog signal conditioner 540 ~ -
to the multiplexer 516 for use by the computer 500. The
:
.
-26-
1065~139
remaining system components illustrated in FIGURE 10 pre-
ferably are the same as those described in connection with
FIGURE 9.
FIGURE 11 illustrates still another embodiment of the
present invention wherein locomotive pulling force FloCo is
calculated as a function of main generator voltage, main
generator current and, in the event locomotive dynamic ~`
braking is being applied, as a function of traction motor
current. Main generator current may be monitored through
the use of a suitable shunt 542 or in any other manner com-
patible with the type of màin generator employed in the
locomotive consist. The signal related to main generator
current may be supplied from the shunt 542 through an analog
signal conditioner 544 to the multiplexer 516 for use by the
computer 500 as required. Main generator voltage may be
monitored across a suitable voltage divider 546.``An output
signal from the voltage divider 546 is then input to a suit-
able analog signal conditioner 548 and onto the multiplexer
516 for use by the computer 500. Traction motor current may
be monitored as previously described in connection with
FIGURE 10.
The remaining system components illustrated FIGURE 11
are preferably the same as those described in connection with
FIGURE 9.
The computer 500 of FIGURES 9, 10 and 11 may be any
suitable conventional general purpose digital computer inter-
faced with external input/output devices in any suitable ~ -~
conventional manner and suitably programmed to perform the
functions described herein. One example of a compact digital
computer which is suitable for the subject system is a Naked
Mini T 16 produced by Computer Automation, Inc. of Irvine,
. -:
106S~39
California 92664. To facilitate an understanding of the
operation of the computer 500 in conjunction with the input/
output devices previously described in connection with
EIGURES 9-11, reference may be had to the flow diagrams of
FIGURES 12A-12G.
System Operation
Referring now to FIGURE 12A, consist data relating to the
physical structure of the train (e.g., car type, lading
weight, etc.) may be supplied to the computer from a suit-
able memory or data storage medium 508 such as a magnetic or
paper tape. The car type data may be used by the computer
as required to locate resistance coefficients and car para-
meters stored permanently in the computer in a table form.
The consist data may then be initially used to calculate a
total train length and weight.
The computer may now draw a display background and non-
changing elements of the output display on the cathode ray
tube. The computer may then request track location from the
engineer by dispïaying a track location request on the cath-
ode ray tube (CRT) display 536. The engineman may then
supply the current track location of the train to the com-
puter by way of the keyboard 504.
With the train location established, data relating tothe vertical and horizontal profile of the track at the estab-
lished location may read from a profile data tape or other
suitable memory 506. The operator may then inialize the com- -
puter clock to the current time of day through the use of the -~
keyboard 504 and train speed may be initialized either auto-
matically or by ~ay of the keyboard 504. The initialized
speed quantity may thereafter be periodically updated as will
be described hereinafter. The computer is then ready to per-
form the train coupler force analysis.
-28-
.: , . . . . .
~06S039
Input data buffers in the m~in compu-t~r memory may
contain data frotr. the external input devicec; and may be peri-
odically checked to assure ~hat the profile data is current
with respeet to the curren~ train location. If the data is
not current, a new block of profile data is read from the
memory 506. When the profile data is current, the track
profile, track curves, mile posts, to~n names and the train
trace are drawn on the CRT display.
The distribution of ear eoupling forces throughout the
train may next be calculated for each car (n) by first set-
ting the value of n at 1 (first car) as is shown in FIGURE
12B. Using the data as to the length of each car in the
train and the location of the head of the train the grade
and eurve values are determined for eaeh ear fro~l the traek
profile data for use in resistance caleulations. The rolling
resistanee ealculations for a ear RRn may be performed from
the ear data, train veloeity, grade and curve values by using
a modified Davis train resistanee equation as previously dis-
eussed in the Mathematieal Model section, note equation (2). - ~ -
The ealeulation of eaeh ear rolling resistanee value is
repeated until the ear eoupler force values are available
for all n ears. The eomputer then eontinues in aecordanee
with FIGURE 12B.
With eontinued referenee to FIGURE 12B, the brake pipe
pressure transdueer 522 provides trainline air pipe pressure
as requested by the eomputer and if a ear braking applieation
is being made, the braking resistance RB for eaeh ear is eal-
eulated as set forth in the Mathematical Model section, note
èquation (3).
Rolling resistance forces FRn are then eorrected to
aeeount for these braking forees FBn to provide a correeted
eoupler foree FRBn at eaeh car-
- -29-
'
.
1~65039
After the distribution of rolling resistance forces
in the train have been computed and corrected for braking
forces, the computer proceeds to determine an acceleration
resistance factor RA by first determinlng locomotive pulling
force FloCo by one of the three alternative techniques pre-
viously described in connection with FIGURES 9, 10 and 11.
In this connection and with reference to FIGURE 12C,
a first method of determining locomotive pulling force is
illustrated. The force between the lead locomotive and the
next adjacent unit of the train may be directly measured by
a dynamometer coupler 512 as previously described in con-
nection ~ith FIGURE 9. This force measure by the dynamo-
meter coupler may be multiplied by the total number of
locomotives to get a total pulling (or braking) force FloCo
The computer may then continue with the calculations as
illustrated and described hereinafter in connection with
FIGURE 12F and 12G to determine car acceleration resistance
values RA (note equation (4) in Mathematical Model section).
Another way in which the locomotive pulling force FloCo
may be determined is illustrated in FIGURE 12D. In this con-
nection, a signal from the traction motor current shunt 53~ :
may be provided to the computer as previously described in
connection with FIGURE 10 and the pulllng force FloCo may be
calculated in accordance with the following equation: ::
F = KRNTMNL (I-I ) - N R i:
loco D s L L ~.
wherein:
K = constant coefficient for particular type
of tractor motor;
R = traction motor gear ratio (typically 65/15); ::
NTM = number of operating traction motors; :
-30-
, .
.. . .
;5039
NL = number of locomotives of this type in consist;
L = running resistance of each locomotive;
I = traction motor current;
S = motor current corresponding to zero motor
torque; and
D = wheel diameter.
Of the foregoing listed quantities employed in the calculation
of the net pulling force of the locomotives, all but traction
motor current are predetermined quantities for a particular
train and may be prestored in computer memory. Traction
motor current may be supplied to the computer as required
for the calculation of FloCo as was previously described.
As a refinement or correction factor to FloCo the com-
puter may be supplied with information as to locomotive inde- ~
pendent air brake pressure from the transducer 522, with -
speed information from the wheel rotation pulse generator
528 and with consist data. Locomotive braking resistance Rb
may then be calculated in accordance with the following equa-
tion:
Rb = PI(AcLe) f ,
wherein:
PI = locomotive independent air brake pressure;
Ac = brake cylinder piston a~a of the nth car,
sq., in.;
= brake lever mechanical advantage of the nth car;
e = brake rigging efficiency of the nth car; and
f = brake shoe to wheel coefficient of friction of
the nth car.
It should be noted that the factors Ac, L and e can be lumped
together and prespecified as a single coefficient for each
locomotive. The coefficient of fricition f as a function of
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, . , ~
-, : . - - . ~ . , .: . .
- 1~65039
speed would be determined from an empirical rela-tionship
according to the type of brake shoes on the locomotive.
A negative independent locomotive air braking resistance
Rb is then added to the uncorrected F1oco to provide an ac-tual
locomoti~e pulling (or braking) force FloCo. The computer
may then continue to the functions illustrated in FIGURES 12F-
12G and calculate car acceleration resistance RAn (note
equation (4)).
A third technique for calculating the locomotive pulling
force is illustrated in FIGURE 12E. If dynamic braking is in
use, the net locomotive braking force Fl ,may be calculated
in response to traction motor current as was previously des-
cribed in connection with FIGURE 12D~ If dynamic locomotive
braking is not being applied the main generator current and
the main generator voltage are monitored as required by the
computer to calculate the locomotive pulling force FloCo in :
accordance with the following equation~
FIoco = ( g g 74sg 7 L L
..:::
wherein: . .
FIoCo = locomotive pulling force, lbs.;
Vg = main generator voltage, volts;
Ig = main generator current, amperes;
Eg = main generator efficiency (approximately 91~
ETM = traction motor efficiency (approximately 96%);
NL = number of locomotives in consist; and
RL = rolling resistance of each locomotive is
calculated from a modified Davis train
resistance formula (note equation (2) supra.)
As discussed in FIGURE 12D, braking resistance Rb due
to locomotive independ~nt air brakes may be optionally added
-32-
,; : .
1065039
to the net tractive effort to provide a corrected locomotive
coupler force Fl .
When locomotive pulling force has been calculated as
described above acceleration coupling forces between cars
throughout the train may be calculated in accordance with
the equations as previously set forth in the Mathematical
~odel section, note equation (4).
Once the acceleration factor RA is calculated the total
force upon each coupler may be calculated FRBAn note equa- :
tion ~1) in the Mathematical Model section. The computer
500 then sends this information through display controller
534 to draw a coupler force distribution diagram 318, upon
the CRT display 536, note FIGU~ 7.
As illustrated in FIGURE 12G, a record keeping routine
may be provided in the computer to provide a record of the
operation of the train. In addition, train location and
train speed may be periodically updated and, when the train
has moved far enough to justify redrawing of the profile, a
new block Qf profile data may be read by cycling the routine
back to point A in FIGURE 12A. If the train has not moved
far enough to justify the redrawing of the profile, a new
cycle may be iniated by cycling back to point B of FIGURE 12B
and onto one of the points Cl, C2 or C3 of FIGURES 12C-12E~
depending upon the technique utilized to determine locomotive
pulling force. -
In summary, the computer 500 operates in conjunction
with the input/output devices as shown in FIGURES 9-11 and
12A-12G to dynamically provide a periodically updated dis-
play of the car coupler forces in the train over the length
of the train. Depending upon the speed of the computer, the
period between successive updates of the force distribution
-33-
- , ~ . .
- ~ -
., . ' ~ . : ,, . . . ::
1065039
may be extremely rapid so as to appear to be a continuous or
an analog update. The coupler force distribution dcita is
displayed against a background which includes a profile of
the track as well as landmarks along the track. From the
displayed information, the engineman can minimize excessive
coupler forces in any one section of the train and more
evenly distribute forces by controlling the throttle setting,
etc.
The foregoing discussion in connection with FIGURES
12A-G provides a logic flow chart for dynamically calculating
individual coupler forces throughout the extent of a train as
the train proceeds along a predetermined route of travel and
dynamically displaying the forces to the engineman. In a
similar vein one skilled in the art will be able to appreciate ~ b
that the foregoing may be supplemented to draw a hypothetical .
force profile 326 which would exist if the locomotive pulling
force were altered to a value different from that actually
measured orcalculated. This concept may then be carried one :
step further to dynamically instruct an engineman, at 334
FIGURE 7, of an optimum throttle setting, or if preferred,
automatically set the throttle to most eff.iciently operate
the train consistant with train action forces, speed limits,
etc. Of course, if the latter mode is selected an engineman
would always be provided with a manual override so that inde-
pendent engineman judgment may be added to the control opera-
tion.
Schematic Display Sequence
Turning now to FIGURES 13-29 of the dra~ings there will
be seen abbreviated schematics of display screens 300 as pre-
viously discussed in connection with FIGURE 7. These sche-
matics will serve to functionally illustrate a dynamic sequence
-34-
'
.. ,: . . . :.
:.
1065039
of train presence on a grade profile and car coupler force
distributions according to a preferred embodiment of the
invention.
Turning specifically now to FIGURB 13 there will be
seen a screen display portion 300 of a cathode ray tube
mounted within the cab of the lead locomotive. Vertical
mile post indicators 304 ~ear a sequential caption 296-299
representing physical mile posts along a predetermined route
of travel of the train.
A transverse undulating trace 710 provides a visual
track grade profile across the screen between the mile post
indicators. ~he train is depicted by trace 712 and is super-
imposed upon the grade line 710.
From the trace 712 it will be appreciated that the
train is approximately one mile long with the locomotive
positioned midway between mile posts 296 and 297 while the
caboose is approaching mile post 296. Accordingly the opera-
tive direction of travel of the train is from left to right
in ascending order of mile post indicators. Functionally
the train trace 712 remains stationary while the grade line
710 and mile posts are moved from right to left.
Directly beneath the train trace 712 is a coupler force
distribution trace 714 which is initialized with respect to
the locomotive by a vertical trace 716. Horizontal trace
718 positioned beneath the coupler force 714 corresponds to -
a zero coupler force value.
The computed coupler force trace 714 of FIGURE13 lndi~
cates that the entire train is in tension, that is the coupler ~
forces between each car is a positive value. In this con- -
nection the locomotive pulling force or the force level of
the trace which intersects vertical reference line 716 at -
-35- -~
., :
.
: : - , : : . ,: ~
1065039
720, for purposes of illustration, may represent 35,000
pounds. At the end of the locomotive the coupler~force is
necessarily zero which therefore rests on the ordinate 718
at point 722.
Between points 720 and 722 individual car coupling
forces may be either positive or negative. At this parti-
cular track location all of the coupler forces are positive
or the entire train is in tension and more particularly
approximately the entire train in advance of mile post 296
is under a tension of approximately 35,000 pounds. Car
coupling tension forces following mile post 296 lineraly
taper down to 0 at the tail end of the train.
Referring now to FIGURE 14, which may be a time event
approximately 30 seconds subsequent to the time event of
FIGURE 13, the mile posts and track profile have been re-
drawn and shifted to the left while the trace 712 remained
stationary to indicate conditions as the train physically
proceeds along the track. In this connection ~ e train is
shown at a position just beyond mile post 297. From the grade
trace it will be appreciated that the ~ntire train is operat-
ing on a descending grade. The throttle setting in the loco-
motive has been reduced and the locomotive coupler pulling
force has been reduced at 724 to approximately 20,000 pounds.
The car coupler force profile 726 indicates that the entire
train is stilliin tension although positive forces are de-
creasing ln the middle of the train.
FIGURE 15 discloses a sequential time event wherein
the mile post 297 is positioned a short distance behind the
locomotive. The locomotive coupler pulling force as at 728
has been kept at 20,000 pounds and a distinct dip in the car
-36-
.. .. . .
' ' , . .., ' . ~ , . .
. ~ . . . .
106S~)39
coupler force profile 730 approxima-tely 15 to 20 cars back
in the train indicates that a run-in train action event is
about to develop.
Proceeding to FIGURE 16 the mile posts and track pro-
file have been redrawn and the train now stands advanced
slightly further with the locomotive coupler pulling force
at 732 still reading 20,000 pounds. The car coupler force
profile 734 approximately in the middle of the train has
gone slightly negative indicating that a run-in train action
event is definitely going to develop unless action is taken.
The slight run-in or negative forces indicated in the middle
of the train at this point in time are probably not yet suf-
ficient to overcome the preload of the draft gears associated
with the car couplers although a run-in is imminent. At this
point in time and superimposed beneath the actual calculated
car coupler force profile 734 a further calculated car coupler
force profile 736 is depicted and indicates that if the loco-
motive pulling force were increased at 738 to 30,GC0 pounds
tension could have been maintained throughout the length of
the train and thus the potential for a run-in action as indi-
cated from the actual calculated profile 734 may be avoided.
In sequential time eventdepicted in FIGURE 17 the mile
posts and grade lines have been redrawn and the train 712 is
advanced relative thereto toward mile post 298. The actual
pulling force on the locomotive as at 740 has been kept con-
stant at 20,000 pounds. The dip in the car coupler force
profile 742 in the rear two-thirds of the train below the
zero value trace 718 indicates compressive forces exist
throughout the rear two-thirds of the train and a run-in is
definitely developing as the train proceeds down the descend- ;
ing grade around mile post 297. Positioned beneath the actual
-37-
. . .
65039
trace 742 is a hypothetical car coupler force trace 746
which indicates that if the throttle position were increased
so as to generate a locomotive coupler pulling force of appro-
ximately 55,000 pounds at 748 the run-in could have been pre-
vented.
In sequential FIGURE 18 the locomotive is beginning to
encounter an ascending grade. If the pulling force by the
locomotive were reduced as at 750 to 15,000 pounds, as an
engineman may select from his feeling of increasing speed in
going down a grade, the negative dip in the car coupler force
profile 752 and the compressive run-in conditions are merely
aggravated. As opposed to decreasing locomotive pulling
force as the engineman may do from his sense of increased
speed in going down a gentle grade the hypothetical profile
beneath the actual car coupler profile indicates that if the
throttle setting were advanced such tha~ the locomotive cou-
pler pulling force were increased to 60,000 pounds as at 754
the coupler force profile 756 could have been maintained posi-
tive throughout the extent of the train and thus the run-in
event could still have been prevented.
Looking now at sequential FIGURE 19 the engineer has
maintained the throttle to produce a locomotive coupler pull- ~ ~
ing force of 15,000 pounds as at 758. The run-in will con- ~-
tinue to develop and the car coupler force profile 760 indi-
cates the rear two-thirds of the train possesses compressive
coupler forces thus indicating that the entire back of the
train is now running-in. The hypothetical force distribution
762 underlying the actual force distribution indicates that
if the locomotive throttle setting were advanced to produce
a pulling force of approximately 50,000 pounds as at 764 a -
run-in may still develop but would only involve about the
back one-fourth of the train.
-38-
. . .
1065039
Proceeding to FIGURE 20 the traln is proceeding up a
slight grade toward mile post 298. The locomotive pulling
force is maintained at about 15,000 pounds as at 766. The
resultant car coupler force distribution 768 indicates that
run-in still developing in the back two-thirds of the train.
The hypothetical distribution below trace 768 indicates that
if the locomotive throttle position were reestablished at a
notch setting operable to produce about 50,000 pounds of
coupler pulling force as at 770 a car coupler force trace
772 resulting therefrom still indicates that a run-in may
develop but will only involve approximately the back one-
fourth of the train.
Sequential FIGURE 21 indicates that the front of the
train is ascending a grade approaching mile post 298. The
pulling force has been increased to 20,000 pounds as at 774,
however, as the car coupler force profile 776 indicates, the
run-in is involving cars closer to the locomotive and approx-
imately three-fourths of the train is almost completely run-
in. If the locomotive engineer were to adjust the notch
setting of the throttle to a position producing approximately
50,000 pounds of locomotive coupler force as at 778 a hypo- -
thetical car coupler force profile 780 could be produced
wherein run-in would be essentially obviated.
In sequential time event depicted in FIGURE 22 the
.!,' .' ~ . '
train has proceeded further up the ascending grade toward
mile post 298. The locomotive throttle setting is such as to
produce a pulling force of approximately 20,000 pounds as at
782, however, the car coupler force profile 784 indicates that
the run-in increasing in intensity in the rear three-quarters
of the train. The intensity or severity of this run-in action
could have been reduced by maintaining the throttle to provide
'
~;''' ' ' ; ' '' ' .,' . '' ." "' ,' ' ,' "''
~. , . ' '. ~ :
,, ~ . - . ....
1~)65039
a coupler force of approximately 50,000 pounds as at 786
wllicll would generate a hypothetical car coupler forc-e dis-
tribution 788.
Referring now to FIGURE 23 the train is approximately at
mile post 298 and has been ascending a slight grade such that
approximately the first half of the train is ascending a grade.
The throttle position has been increased to approximately
27,000 pounds as indicated at 790 and the car coupler force
distribution 792 indicates that positive coupler values are
proceeding from the front of the train to the rear. Thus this
indicates that the front of the train is becoming tensioned
and the zero crossover point from tension to compression is
progressing toward the rear of the train. The train is now ~ -
running out. The hypothetical coupler force trace 794 indi-
cates that if the engineer had kept the throttle position set
to approximately 50,000 pounds as at 796 the trail end of the
train would not yet be running out.
In FIGURE 24 the train has just passed mile post 298
with the throttle position set so as to generate a locomotive
pulling force of 27,000 pounds as a~ 798. The car coupler
force profile 800 indicates that the front half of the train
is in tension and the rear half of the train is run-in or in
compression. The hypothetical underlying force profile 802
indicates that if the engineer had maintained the throttle
position such that a locomotive coupling pulling force of
50,000 pounds as at 804 were produced the point of transition
from positive to negative forces would have remained stationary
and the run-out would not have started.
Turning now to FIGURE 25 the train has advanced still
further past mile post 298 toward mile post 299. The loco-
motive throttle has been increased so as to produce a
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locomotive coupling force of 33,000 pounds as at 806. This
increase in pulling force is a typical operational character-
istic for an engineer so as to maintain speed of the train
upon an ascending grade. Tension or run-out in the front
half of the train is evident from the car force profile 808
and is proceeding toward the rear of the train. If the
engineer had repositioned the throttle to a setting operable
to produce a pulling force of approximately 50,000 pounds as
at 810 the car force profile 812 would indicate that although
a run-out is occurring it has not yet reached the rear of the
train.
Advancing now to FIGURE 26 the train is still proceed-
ing toward mile post 299 on an ascending grade. The loco-
motive engineer has increased the throttle settingto!generate
a locomotive coupling or pulling force of approximately 40,000
pounds as indicated at 814. The resultant car coupler force ~ -
profile 816 indicates that run-out is still developing and a
very small number of cars are run-in at the tail end of the
train. If the engineer had maintained the throttle setting
to generate a pulling force of 50,000 pounds as indicated at
820 the run-out would be about the same as it would have been
if the pulling force were 40,000 pounds as indicated at 816. ~-
Turning now to FIGURE 27 the train is still advancing
toward mile post 299. The engineer has positioned the throttle
such as to produce a locomotive coupling force of 40,000 pounds
as at 822. The car coupling force profile 824 indicates that
the entire train is in tension and coupling tension forces ;
exist~throughout the train. At this point in time the engi-
neer could have reduced the throttle setting to generate a
puliing force of approximately 20,000 pounds as at 826 and
still have maintained tension throughout the train as indi-
cated by car coupler profile 828.
- ~ ,......
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~ -. '. ~, ' : .,:
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~ IGURE 28 depicts sequential time event wherein the
train has advanced to a posture wherein the locomotive is
approximately midway between mile posts 298 and 299. The
engineer has further increased the throttle setting so as
to produce a coupling force of approximately 50,000 pounds
as at 830 thus maintaining tension or run-out profile 832
throughout the train. The engineer, however, could have
reduced the throttle setting to a position generating a loco-
motive pulling force of only 20,000 pounds as indicated at
834 and still have maintained a stretched or tension mode of
the entire train as indicated in hypothetical car coupler 836.
The final time sequence event depi.cted in FIGURE 20 dis-
closes the train in a position advanced still further toward .;
mile post 299 wherein the locomotive is positioned at the
apex of the track grade profile. The engineer has reduced
the locomotive throttle setting so as to produce a locomotive
pulling force of approximately 40,000 pounds as at 840. How-
ever, the car coupler force profile 84~ indicate.~ that tension
forces of about 75,000 pounds are exhibited at a peak point
approximately in a midspan portion of the train thus indicat- ~ :
ing that forces in the train can far exceed the net pulling
force exerted by the locomotives. The hypothetical force
profile 844 indicates that the engineer could have cut the .
throttle back to idle thus producing zero locomotive pulling
force at 846 and still have maintained the entire train in
tension.
The foregoing discussion of a train operational sequence
for approximately two miles over a typical track grade profile
is not intended to be exhaustive but merely illustrative of
run-in and run-out events that may occur and corrective action
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that may be taken by a locomotive engineer if presented with
appropriate force distribution profiles as the train is pro-
ceeding along a predetermined route of travel.
SUMMARY OF MAJOR ADVANTAGES OF THE INVENTION
From the foregoing detailed descrip~ion of preferred
embodiments of the invention several unique and highly advan-
tageous methods and apparatus for facilitating control of a
train have been delineated.
More particularly a projection of the track and train
profiles within the cab of the locomotive enables an engine-
man to more effectively and efficiently control a train. -~
Additionally dynamic train presence monitoring enables
even an inexperienced engineman to efficiently operate long
trains of widely varying consist over widely varying terrains.
At the same time optimum speed performance may be otbainedi
accurately consistant with speed and safety limits, by the
advantageous utilization of descending grades. Such
accurate control, of course, ultimately enables fuel consump-
tion to be minimized.
Further, by the provision of the subject system, loco-
motive coupling forces may be determined by one of three
techniques and the remaining individual car coupling forces
may be dynamically calculated to provide an engineman with
car coupling force distributions without requiring an expen-
sive and impractical physical measurement of coupling force
at each coupler shank.
By the provision of a force profile display throughout
the length of the train the engineman may take corrective
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10t;5039
action such as speeding up or slowing down the locomotive,
applying or releasing the train brakes, locomotive indepen- -
dent air brakes, or locomotive dynamic brakes in order to
obviate or minimize the occurrence of a train action event
somewhere throughout the length of the train.
The cathode ray tube display screen provides a capa-
bility for displaying to the locomotive engineer helpful and
necessary operational information and instructions so as to
permit an inexperienced engineman to effectively operate an
extremely long modern train in a manner far exceeding the
capabilities of even the most skilled "seat-of-the-pants"
engineers.
Yet further a significant advantage is provided by an
effective means to accurately record and store train opera-
tional parameters such as speeds, throttle settings, braking
applications, etc. in conjunction with grade profile, speed
limits, town locations, etc.
The above specification for economy of presentation
specifically discloses the invention with respect to a train
comprised of a lead locomotive set only. The foregoing dis-
closure, however, will enable one skilled in the art to
readily adapt the components and equations disclosed herein
to trains lncluding one or more mid-train locomotive units as
desired.
While the invention has been described with reference -~
to preferred embodiments it will be appreciated by those
skilled in the art that additions, deletions, modifications
and substitutions or other changes not specifically described
may be made which will fall within the purview of the appended
claims.
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