Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE
AUTOMATIC BAIL OFF FOR LOCOMOTIVE BRAKING SYSTEM
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
[0001] The present invention relates to locomotive braking systems and,
more
particular, to an automatic bail off during brake applications.
2. DESCRIPTION OF THE RELATED ART
[0002] A locomotive operator using a pneumatic or electro-pneumatic
braking system
is required to make a reduction in the brake pipe (BP) pressure to apply the
train brakes. Due
to operating rules or conditions of train control, the locomotive operator may
have to perform
a bail off that prevents the locomotive brake cylinders from applying while a
reduction in
brake pipe pressure is made to apply the train brakes. Generally, the term
bail off is used to
refer to the removal of pressure from the brake cylinders of a locomotive or
multiple
locomotives in a consist.
[0003] To accomplish the application of the train brakes and a bail off
of the
locomotive brakes, the locomotive operator must perform two operations
simultaneously,
which typically requires the use of both hands on the equipment that allows
the operator to
apply the train brakes while preventing the locomotive brake cylinders from
applying. A
locomotive operator has, however, many other demands on his or her attention
in situations
where the train brake are being applied. The act of bailing off the locomotive
brakes must
happen regardless of the situation and therefore is an added activity that can
distract from
other decisions and actions that the locomotive operator must perform, such as
determining
the appropriate amount of brake pipe reduction to be made, deciding whether
dynamic
braking should be applied, etc. Similar decisions and operations must also be
made in
electronically controlled pneumatic (ECP) brake control systems with respect
to the train
brake command (TBC) communication level and the resulting effect on the
locomotive brake
cylinder pressure. Accordingly, there is a need in art for a system that can
reduce the level of
input needed from the locomotive operator to bail off the locomotive brakes
during a train
braking event.
BRIEF SUMMARY OF THE INVENTION
[0004] The invention comprises a system for automatically bailing off a
train having a
locomotive braking system with at least one locomotive brake cylinder.
[0005] The system includes a controller programmed to determine when an
operator
of the train has initiated a brake application and to send a bail off command
to the locomotive
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braking system that results in a release of a predetermined amount of pressure
from at least
one locomotive brake cylinder. The controller may be integrated with or
coupled to a
conventional train braking system, which has a locomotive operator input with
a train brake
handle and an independent brake handle, and is interconnected to the rail car
braking system
and locomotive braking system. The locomotive braking system responds to the
bail off
command sent by the controller by releasing the predetermined amount of
pressure from at
least one locomotive brake cylinder.
[0006] In one approach, the controller is programmed to determine whether
the
operator of the train performed a manual bail off of the locomotive braking
system in
connection with a prior train brake application and to enable the sending of
the bail off
command only if the operator of the train performed the manual bail off The
controller is
further programmed to send the bail off command if the operator of the train
performed a
manual bail off of the locomotive braking system in connection with a prior
train brake
application and the operator of the train subsequently initiates another brake
application. The
controller is also programmed to determine whether the operator of the train
has requested a
subsequent brake application beyond the equivalent of a full service brake
and, if so, to send
a command cancelling the bail off.
[0007] In another approach, the controller is programmed to determine
whether the
operator of the train has initiated a brake application between a minimum
service brake
application and a full service brake application and to send the bail off
command if the brake
application is between a minimum service brake application and a full service
brake
application. The controller is also programmed to determine whether the
operator of the train
has requested a subsequent brake application beyond the equivalent of a full
service brake
and, if so, to send a command cancelling the bail off
[0008] In a further approach, the controller is programmed to determine
whether there
is an end of train signal and to only send a bail off command if there is an
end of train signal.
[0009] In an additional approach, the controller is programmed to
determine if the
locomotive is in lead cut-in prior to sending a bail off command. The
controller is also
programmed to determine that locomotive is not in an emergency state prior to
sending a bail
off command. The controller is further programmed to determine that the
locomotive is not
in a penalty state prior to sending a bail off command.
[0010] The controller may be programmed to perform any one of or all of
the various
approaches to performing an automatic bail off, thereby relieving the operator
of the
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responsibility to manually input the train braking command into a first manual
input as well
as manually performing a bail off of the locomotive brakes using a second
manual input.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0011] The present invention will be more fully understood and
appreciated by
reading the following Detailed Description in conjunction with the
accompanying drawings,
in which:
[0012] FIG. 1 is a schematic of a system for automatically providing a
bail off of the
locomotive brakes during a train brake application according to the present
invention;
[0013] FIG. 2 is flowchart of a bail off process for a system for
automatically
providing a bail off of the locomotive brakes during a train brake application
according to the
present invention;
[0014] FIG. 3 is flowchart of another bail off process for a system for
automatically
providing a bail off of the locomotive brakes during a train brake application
according to the
present invention
[0015] FIG. 4 is flowchart of a further bail off process for a system for
automatically
providing a bail off of the locomotive brakes during a train brake application
according to the
present invention;
[0016] FIG. 5 is flowchart of an additional bail off process for a system
for
automatically providing a bail off of the locomotive brakes during a train
brake application
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Referring now to the drawings, wherein like reference numerals
refer to like
parts throughout, there is seen in FIG. 1 a system 10 for automatically
providing a bail off of
the locomotive brakes during a train brake application, referred to herein as
an automatic bail
off operation. More particularly, system 10 comprises an automatic bail off
controller 12,
which may be provided by programming the existing programmable elements of
train braking
system 14 of a locomotive 16 or by providing controller 12 as a separate
module that is
interfaced with train braking system 14, such as by interconnecting controller
12 to a network
bus such as those typically included with the electronic brake valve and
processor of an
electronically controlled train braking system 14. Train braking system 14 is
interconnected
to a locomotive operator braking input 18, which can include a train brake
handle 20 as well
as an independent brake handle 22. Train braking system 14 is also
interconnected to the
locomotive braking system 24 and the rail car braking system 26.
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[0018] Regardless of whether controller 12 is integrated into train
braking system 16
or provided as a separate module, controller 12 is programmed to perform
certain decision-
making procedures in response to receiving an input from the locomotive
operator via input
18 as well as other braking system conditions and, when appropriate, issues
the appropriate
commands to locomotive braking system 24 to perform a bail off of the
locomotive brakes
without any additional manual inputs from the locomotive operator, such as the
operator
having to physically move independent brake handle 22. The commands sent by
controller
12 may comprise a signal such as an independent actuating and release (IA&R)
pressure, an
electrical signal, or a communication signal sent through a serial
communication port or a
train network, that cause locomotive braking system 24 to bail off the
locomotive brakes
during a train braking operation. The automatic bail off operation can be
configured to result
in a complete exhausting of the locomotive brake cylinder pressure to zero
pounds per square
inch (psi) or to a predetermined minimum locomotive brake cylinder pressure,
such as 10 psi,
that is sufficient to minimize train run-in during a train brake application
while still allowing
the locomotive braking system to provide some braking force to the train. The
automatic bail
off operation may also be configured to operate in conjunction with locomotive
braking
system 24 to initially bail off to a zero psi pressure level in the locomotive
brake cylinders
and then gradually increase the locomotive brake cylinder pressure over a
predetermined time
period and at a predetermined rate to eliminate train run-in during the
initial brake application
while minimizing the train stopping distance by restoring the locomotive
brakes to a level
that helps brake the mass of the locomotive(s) after the train brake
application has had time to
propagate through the entire train. The predetermined time period and
predetermined rate
may be determined based on factors such as the particular composition of the
train, the
requirements of the applicable governmental safety regulations, or customer
preferences.
[0019] As seen in Fig. 2, system 10 may be configured to implement a bail
off
process 30 wherein controller 12 is programmed to initiate an automatic bail
off operation
based on prior manual braking applications performed by the locomotive
operator. For
example, once a brake application has been initiated by the train operator 32,
controller 12 is
programmed to perform a check 34 to determine whether a bail off operation was
manually
made in combination with a prior train brake application that was initiated by
the operator. If
so, controller 12 is enabled to perform an automatic bail off operation during
the next train
brake application 36. If a subsequent check 38 determines that a brake
application has been
initiated by the locomotive operator, controller 12 sends a bail off command
40 to locomotive
braking system 24 to perform a bail off operation without any additional input
from the
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locomotive operator. The bail off command may be configured to initiate a bail
off operation
for a predetermined time period, such as a default pre-established by the
owner of system 10.
Alternatively, the predetermined time period may be adjusted dynamically based
on the
amount of brake pipe reduction made by the operator, the size of the
locomotive consist, or a
target locomotive brake cylinder pressure. Finally, a check 42 is performed to
determine
whether the operator has changed the braking requirement, such as by moving
the brake
handle beyond the "full service" position or to another predetermined position
and, if so, a
command is sent by controller 12 to locomotive braking system 24 to cancel the
bail off 44.
[0020] As seen in Fig. 3, system 10 may be configured to implement
another bail off
process 50 wherein controller 12 is programmed to send a command initiating an
automatic
bail off operation in response to any manual brake application between
"minimum" and "full
service" that is requested by the locomotive operator. Thus, after a brake
application has
been initiated by the operator 52, a check 54 is performed to determine
whether the operator
has moved the train brake handle between the "minimum" and "full service"
positions (or any
other defined positions). If so, automatic bail off operations are enabled 56
and a command
is sent to locomotive braking system 24 to perform a bail off operation 58
without any
additional input from the locomotive operator. A check 60 is then performed to
determine
whether the operator has changed the braking requirement, such as by moving
the brake
handle beyond the "full service" position or to another predetermined position
and, if so, the
bail off is cancelled such as by controller 12 sending a command cancelling
the bail off 62.
In this process 50, as with other embodiments, the locomotive operator has the
option at any
time of manually performing a bail off procedure using the independent brake
lever or
executing an emergency brake application, which would be identified by check
60 and result
in a cancelling of the automatic bail off operation.
[0021] As seen in Fig. 4, system 10 may be configured to implement a
further bail off
process 70 that determines whether there are freight cars attached to the
locomotive or
locomotive consist to mitigate the safety risk of a light locomotive. After a
brake application
has been initiated 72, a check 74 is performed of the end of train (EOT) brake
pipe pressure
signal available from the EOT in the locomotive to determine whether there is
an EOT brake
pipe pressure. If there is not any EOT brake pipe pressure, automatic bail off
of controller 12
is disabled 76. If there is EOT brake pipe pressure at check 74, controller 12
is enabled 78 to
send a command initiating an automatic bail off procedure and a command is
send 80. In lieu
of EOT brake pipe pressure, several other data items may be used as the
triggering condition
at check 74, such as a confirmed EOT communications address, an EOT heartbeat
signal, or
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an EOT GPS signal, may be used as an EOT signal that allows controller 12 to
enable the
automatic bail function. As before, a check 82 may be made to determine
whether the brake
requirement has changed and, if so, a command sent to cancel the bail-off 84.
[0022] As seen in Fig. 5, controller 12 may be programmed to implement a
process
90 where automatic bail off operations are enabled in response to an operator
input to the
locomotive driver's interface display or a momentary switch on the operative
driver's control
stand. First, automatic bail off operation is manually enabled by the operator
92. For safety,
controller 12 is programmed to disable automatic bail off operation if a check
94 determines
that the locomotive is not in lead cut-in, a check 96 determines that the
locomotive is in an
emergency state, or a check 98 determines that the locomotive is in a penalty
brake state. In
the event that controller 12 has disabled automatic bail off operation because
of checks 94,
96, or 98, the operator must re-enable the function by manually enabling
automatic bail off
operations 92. If checks 94, 96, or 98 pass, and a brake application is
subsequently initiated
by the operator 100, controller 12 sends a command to perform a bail off 102.
If a check 104
determines that the brake requirement has changed, a command cancelling the
bail off is sent
106. If any of checks 94, 96, or 97 are negative, automatic bail-off operation
is disabled 108.
[0023] As seen in Fig. 6, processes 30, 50, 70, and 80 may be implemented
simultaneously or made available in a single system 10 that allows for an
automatic bail off
operation to be enabled or disabled according to default settings, operator
input, or the
conditions of locomotive braking system. Thus, the controller may be
programmed to
perform any one of or all of the various approaches to performing an automatic
bail off,
thereby relieving the operator of the responsibility to manually input the
train braking
command into a first manual input as well as manually performing a bail off of
the
locomotive brakes using a second manual input.
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