Definitions Relevant to Navy Rail Operations

AIR BRAKE. The braking system used on all railcars.

AIR BRAKE HOSE. The flexible hose at each end of a railcar which is threaded into the brake

pipe angle cock at one end, and has a glad hand fitting at the other end which engages with a

similar coupling on an adjoining car.

AMPERE. The fundamental unit of measure for electric current. One Ampere is defined as the

current that flows when a potential of one volt is impressed on a resistance of one Ohm.

ANGLE BAR. One of two steel bars used to join rail ends together to form continuous track,

(sometimes called "joint bar").

ANGLE COCK. A special type of 1-1/4" valve of either ball or plug design, located at both

ends of the brake pipe on locomotives and railcars and used to control admission of air to the

brake pipe on individual cars. The free end is angled at 45 degrees and is threaded to receive the

threaded end of the air hose.

'B' END OF CAR. The end on which the hand brake is located. Commonly used with "L" or

"R" to designate either the left or right side when facing the "B" end, i.e., "BL" or "BR," "AL" or

"AR".

BALLAST. Angular crushed stone used for placement on the roadbed for the purpose of holding

the track in line to ensure it is properly surfaced. Distributes and transfers railcar loads from the

tie to the subgrade and provides for drainage.

BARRICADED SIDING. A siding within concrete or earth walls to contain hazardous material

loaded cars.

BEARING, JOURNAL. The general term used to describe the load bearing arrangement at the

ends of each axle of a railcar truck. Plain journal bearings are also known as "friction bearings",

blocks of metal, usually brass or bronze, shaped to fit the curved surface of the axle journal, and

resting directly upon the bearing, with lubrication provided by free oil contained in the journal

box. Journal roller bearings are sealed assemblies of rollers, races, cups and cones pressed onto

axle journals and generally lubricated with grease. Vertical loads are transferred from the journal

bearing to the truck side frame through the journal bearing wedge (plain bearing design) or

through the roller bearing adaptor in roller bearing trucks.

BLEED. Remove air from a railcar brake system. ABD railcar brake valves allow the brake

cylinder to be bled while saving the air in the reservoirs on the car or, if desired, the entire car air

system can be bled. AB railcar brake valves bleed the entire system.

BLOCK. A length of track of defined limits, the use of which is controlled by block occupancy

directives.

BLUE FLAG. A blue signal (blue flag by day, a blue light by night), displayed at one or both

ends of the locomotive, car, train, or track indicating that workmen are in, on, under, between or

around the equipment. Equipment with blue flag protection shall not be moved or coupled into.

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