Section 12
Glossary
Accelerometer
An instrument that displays in MPH per minute the rate of speed increase or decrease.
Actuate
Action required to prevent a brake application on the locomotive(s) by releasing locomotive brakes after an automatic brake application. Actuate before the automatic brake application for 4 seconds per locomotive in the consist after the exhaust has ceased.
Adhesion
The coefficient of friction between the wheel and the rail of a car or locomotive. Adhesion indicates the amount of rotating force the wheel can place on the rail before wheel slip occurs during acceleration or deceleration.
Air Flow Indicator
An instrument that measures the air flow through the automatic brake valve to the brake pipe.
Alerter
A device that initiates a penalty brake application when the Reset Safety Control (RSC) times out. Timing out of the RSC occurs when one of the reset devices is not used by the engineer. Example of a reset occurs when the engineer operates the horn, moves the throttle or dynamic brake handle, actuate the engine brakes or pressing the reset button.
Alignment Control Couplers
Specially equipped couplers that limit lateral movement and reduce lateral forces on the track. These couplers minimize rail turnover, wheel climb, and jackknifing.
Angle Cock
A device used to open and close the brake pipe on the ends of locomotives and cars. To open, move the handle in line with the brake pipe. To close, move the handle at a right angle to the brake pipe. Note that these positions are the opposite of cutout cock positions.
Articulated Car
A car constructed by permanently connecting two or more platforms with an articulated joint (two platforms share a common truck).
Automatic Air Brake System
The piping, reservoirs, and valves that operate the air brake system on locomotives and cars. Reducing brake pipe pressure at a service or emergency rate automatically applies the brakes. Increasing brake pipe pressure above auxiliary reservoir pressure releases the brakes.
Automatic Brake Valve
A device that controls the flow of main reservoir air into the equalizing reservoir and brake pipe to charge and release brakes. The automatic brake valve also reduces equalizing reservoir and brake pipe pressure at either a service or emergency rate.
Automatic Brake Valve Cutout Valve
A device used to cut the automatic brake in or out.
Automatic Reporting Unit (ARU)
A reporting device, used during winter operation, consisting of a cell phone which is plugged into an unattended locomotive’s MU connection. Should the locomotive shut down, the ARU will automatically telephone a preprogrammed number a deliver message that the locomotive has shut down.
Auxiliary Reservoir
A storage volume for compressed air on locomotives and cars. It is charged from the brake pipe and provides air pressure for service and emergency brake applications.
”B” End (of car)
The end where the hand brake is located, unless otherwise identified.
Back-Up Valve or Hose
A device, either portable or permanently connected to the brake pipe, that controls brakes from the car it is attached to. The device can be used to apply the brakes with a service or emergency application.
Bleed Venting
Allowing air pressure to escape to the atmosphere.
Blended Braking
Using automatically controlled mixed air and dynamic braking at the same time to provide a retarding force on cars and locomotives.
Bolster Stop
A device that, when properly installed, limits the lateral movement of a drawbar.
Brake Cylinder Release Valve (bleed valve)
The valve that initially bleeds brake cylinder pressure. If held open, it will bleed off auxiliary and emergency reservoir pressures.
Brake Pipe
The pipe, angle cocks, hoses, and hose couplings that distribute compressed air throughout the automatic brake system.
Brake Pipe Gradient
The difference in brake pipe pressure between the locomotive (or source of supply) and the rear car of the train. Brake pipe gradients may be:
· True Gradient: The gradient that exists when the system is fully charged.
· False Gradient: The temporary gradient that exists when the system is less than fully charged (for example, the exaggerated difference between the head end and rear end after a release);
or
· Inverse Gradient: The temporary condition when the brake pipe pressure is higher at the rear of the train than at the head end of the train (for example, at the beginning of a service brake application).
Branch Pipe Cutout Cock
A device on locomotives and cars that isolates the control valve from the brake pipe.
Buff Force
Compressive coupler forces that occur during a slack-bunched condition.
Check Valve
A valve that allows air flow in one direction only.
Coefficient of Friction
The ratio between the braking force caused by brake cylinder pressure and the resulting retarding force of the brake shoe at the wheel.
Communications Display Unit (CDU)
The CDU accepts, analyzes and displays information relevant to the rear of the train. The CDU provides audible alerts and displays to assist the locomotive engineer in the handling the train. In additional, the CDU is equipped with an emergency braking feature to be used in the event of a loss of the normal braking capability on the locomotive.
Control Valve
The valve on locomotives and cars that charges reservoirs and applies or releases brake cylinder pressure in response to changes in brake pipe pressure.
Cutout Cock or Valve
A device used to cut in or cut out certain air brake functions. To open (cut in), move the handle at a right angle to the pipe. To close (cut out), move the handle in line with the pipe. Note that these positions are the opposite of angle cock positions.
Cycle Braking
The process of applying, releasing, and reapplying train brakes to control speed without completely recharging the train brake system.
Dead Engine Device
A device near the locomotive control valve used when a locomotive unit is handled dead-in-train (hauled like a box car). When the dead engine cutout cock is opened, the No. 2 main reservoir is charged from the brake pipe to operate the engine brakes.
Dead-in-Train
See ”Hauled in-Train.”
Disturbed Track
A section of passable track that has a temporary speed restriction imposed on it either because of various defects or because track maintenance has affected the integrity of the track.
Draft Force
Pulling force (tension) on couplers and draft gear during a slack-stretched condition.
Draft Gear
A cushioning device that transmits draft or buff forces between the coupler and the car or locomotive frame.
Drawbar Forces
The longitudinal forces at the couplers between cars or locomotives. The forces may be draft or buff, depending on train operation.
Dynamic Brake
The system that electronically converts energy created by the momentum of a moving locomotive into an effective retarding brake.
Emergency Application
A reduction in brake pipe pressure at a rate sufficient to cause control valves to move to the emergency position.
Emergency Brake Valve
The valve used to initiate an emergency brake application. It is found on locomotives, cabooses, passenger cars, and some work equipment.
Emergency Reservoir
A storage volume on cars for compressed air. This reservoir is charged from the brake pipe and provides air pressure for emergency brake applications and certain recharge features.
End-of-Train Telemetry Device (EOT)
A system of components that determines the rear car brake pipe pressure and transmits that information to the display on the head-end display unit.
Equalizing Reservoir
A small reference volume on locomotives used to make service brake applications.
Foreign Line Locomotive
Any locomotive not owned by Canadian Pacific Railway.
Foundation Brake Gear
The levers, rods, brake beams, etc. that connect the brake cylinder piston rod to the brake shoes. When air pressure forces the piston out, the brake shoes are forced against the wheels by means of this gear.
Full Service Application
A service reduction of brake pipe pressure that equalizes the pressure between the brake cylinder and the auxiliary reservoir.
Grade
The slope of railway track measured by the number of feet of rise or fall in 100 feet of horizontal distance. One foot of rise or fall in 100 feet of horizontal distance equals a 1.0 percent grade. Grade designations include the following:
· Light Grade: 0.80 percent to 1.0 percent
· Heavy Grade: 1.0 percent to 1.8 percent
· Mountain Grade: 1.8 percent or greater
· Cresting Grade: A long ascending grade that changes with enough magnitude to require a change in train handling procedures.
Gradient
See ”Brake Pipe Gradient.”
Graduated Release
A feature in locomotive and passenger brake equipment that allows brake cylinder pressure to be reduced in steps proportional to the increase in brake pipe pressure. This feature allows the operator to reduce the braking effort on passenger equipment without releasing and reapplying the automatic brake.
Hand Brake
An assortment of levers, chains, rods, and gears. When applied manually by wheel or lever, the hand brake forces the brake shoes against the braking surfaces (wheel tread or disc) to control car or locomotive movement.
Harmonic Rocking
The excessive lateral rocking of cars and/or locomotives that may result in wheel lift. Harmonic rocking usually occurs at speeds between 13 and 21 MPH on jointed rail.
Hauled-in-Tow
Hauling locomotive(s) in a train without the MU air hoses coupled and cut in.
Head-of-End Display Unit
A telemetry transmitter/receiver that provides the locomotive engineer with the displays and controls needed to monitor and operate the associated Sense and Braking Unit (SBU). When the term head-end display unit is used, it refers to the CPR’s TIBS head-end devices mounted in the locomotive. These head-end display units are also known as IFD, ICE, CDU, IDU or CLU.
Helper
One or more manned locomotives added to a train to assist movement.
In-Train Forces
Any force occurring within a train. Examples include buff, draft, run-in, and run-out. Excessive in-train forces may result in break-in-two, jackknifing, stringlining, damage to lading, etc.
Independent Brake
A device used to operate the air brakes on a locomotive apart from the automatic brakes.
Independent Pressure Switch (IPS)
A device on a locomotive that cancels the extended range portion of dynamic braking or all dynamic braking when enough independent brake cylinder pressure is applied. This switch prevents the locomotive wheels from sliding because of excessive braking.
Integrated Cab Electronics (ICE)
The feature that uses computer controlled display screens to integrate the control stand functions with the operator controlled electronics.
Integrated Function Display (IFD)
IFD is a ten inch diagonal, back light, color graphics liquid crystal display (LCD) with up to 8 menu soft keys arranged horizontally below the screen.
Jackknifing
When the center sill between two rail vehicles is excessively misalign or the coupler is angled sharply. Usually caused by excessive buff forces.
L/V Ratio
The ratio of lateral force (a wheel trying to climb the rail) to the vertical force (weight of a car or locomotive and its load). Excessive L/V ratios can contribute to rail turnover, wheel climb, and derailments.
Locomotive
A unit or combination of units propelled by any form of energy and operated from a single control.
· Light Locomotive: A locomotive operating without cars.
· Locomotive Consist: One or more units with multiple unit (MU) connectors coupled, cut in, and operated from a single control.
Main Reservoir
A reservoir on a locomotive that stores, cools, and dries the supply of compressed air.
Minimum Reduction
A 6 to 8 psi service brake pipe reduction. It takes advantage of the ”quick service” feature and minimizes in-train forces caused by the serial action of a brake application.
MU-2-A Valve
A device used to cut the independent brake valve in or out.
Multiple Unit (MU) Connections
The hoses and cocks at both ends of locomotives that connect air brake equipment in a locomotive consist, allowing operation from a single control. MU connections include:
· Actuating: When charged with main reservoir air, causes a release of an automatic brake application on locomotives.
· Independent Application and Release: Controls independent brakes on locomotives from a single control.
· Main Reservoir (MR): Equalizes the main reservoir pressure between locomotives.
· Brake Pipe: The pipe, angle cocks, hoses, and hose couplings that distribute compressed air throughout the automatic brake system.
Over-Reduction
A service brake pipe reduction to a pressure lower than a full service application.
Overcharge
When brake equipment on cars or locomotives is charged to a pressure higher than the regulating valve setting.
Penalty Brake Application
An automatic brake application at a service rate caused by a safety control device, such as an electronic alertness device (alerter), overspeed, or foot pedal.
Person in Charge
While the air brake tests are being conducted, the person performing the test is considered the person in charge of the train at that time. The person in charge must determine that all employees are safely positioned before giving authority to set or release train air brakes.
Planned Braking
The braking process that occurs when the engineer has enough time and distance to slow, control, or stop the train in the safest and most efficient manner.
Qualified Person (QP)
A trainman given fundamental training on freight car inspections and air brake tests. All CPR trainmen are Qualified Persons in the application of these rules.
Qualified Mechanical Inspector (QMI)
A person, such as a carman, with more extensive training in air brake testing and maintenance that provides for a more detailed inspection.
Reduction Relay Valve
A device on long cars that helps reduce brake pipe pressure during service and emergency brake applications. The valve compensates for the added length of brake pipes on long cars.
Regulating Valve
Is a device located at the automatic brake valve which controls the maximum pressure put into the equalizing reservoir and brake pipe. The air that is controlled is supplied by the locomotive main reservoir and delivered to the automatic brake system.
Reset Safety Control (RSC)
See Alerter
Run In
The rapid change of the train’s coupler slack to buff (compressed).
Run-Out
The rapid change of a train’s coupler slack to draft (stretched).
Running Release
The release of an automatic brake application while the train is moving.
Safety Control Devices
A variety of safety devices including event recorders, alerters, deadman controls, automatic cab signals, cab signal whistles, automatic train stop equipment and automatic train control equipment.
Sag
A descending grade followed by a level, nearly level or ascending grade. These combinations of changes in grade require adjustments in train handling to control slack.
Sense and Braking Unit (SBU)
A device mounted on the side of the trailing coupler casting and coupled to the brake pipe on the rear car of a train. The SBU senses brake pipe pressure, motion and direction and transmits this information to the head-end of the train.
Service Brake Application
A reduction of brake pipe pressure at a controlled rate that causes the control valve to move to a service position and apply the brakes.
Slack Action
Movement of part of a coupled train at a speed different from another part of the train.
Slug
A unit with traction motors but no diesel engine and no capability to propel itself. The unit receives electrical power through a power cable from an adjacent, specially equipped locomotive. Slugs are used where low speeds and high tractive effort are needed.
The preferred method of applying train brakes. An initial 6 to 8 psi brake pipe reduction followed by additional reductions in 2 to 3 psi increments spaced 30 seconds apart. This method reduces in-train forces.
Stretch Braking
Slowing or stopping a train using the automatic air brakes and enough power to maintain a slack-stretched condition.
String Lining
The result of excessive draft forces in a train negotiating a curve. Stringlining causes wheel climb, track damage, or derailment.
Thermal Cracks (in wheels)
Cracks in a railroad wheel, normally caused by heat generated on the tread and flange of the wheel from excessive braking.
Throttle Modulation
Adjusting the throttle one notch at a time to control train speed and in-train forces without applying air brakes.
Tons per Operative Brake
The measurement calculated by dividing the gross trailing tonnage of a train (not including the locomotive) by the total number of cars with operative air brakes.
Tractive Effort
The force exerted by a locomotive on the track to move a train. Tractive effort is measured in pounds and decreases as locomotive speed increases.
Tractive Effort Meter
The device that indicates the tractive effort being produced by a locomotive with AC traction motors. It reads as a percentage of rated tractive effort or a display showing pounds of tractive effort.
Train Separation
Any unplanned train separation involving mechanical coupling equipment (knuckles, drawbars, etc.).
Two-Compartment Reservoir
A component on cars that contains both the auxiliary and emergency reservoirs.
Undesired Emergency (UDE)
An undesired emergency application of a train’s air brake system (also known as a “dynamiter” or ”kicker”).
Yard Test Plant
A supply of compressed air in a yard that is used to charge and test trains.