CENTER SILL. The main longitudinal structure member of a railcar underframe, often
constructed as a large box section or hat section. The center sill receives all of the buff and draft
forces created in train handling and switching.
CLEARANCE (Dimensions). Railcar dimensions that cannot be exceeded.
COMPROMISE JOINT. Joint bars designed to connect rails of different height and cross
CONSIST. The make up of a freight train by types of cars and their contents.
COT&S. An acronym that stands for "Clean, Oil, Test and Stencil" and refers to the periodic
servicing of a railcar's brake system components.
COUPLER. The device used to connect any railcar to another railcar or a locomotive. A
coupler includes a draw head, links, pins, and a knuckle.
COUPLER EXTENSION. A metal connector that attaches between railcar or locomotive
couplers and permits additional swing for operation on close curves.
CRANE RAIL. Rail used to support cranes.
CROSSING, HIGHWAY. The point where a railroad track and a road cross at grade.
Highway crossings are normally protected by signs, or signs and flashing lights, or signs, flashing
lights, and gates.
CROSSING, RAIL. The point where two railroad tracks intersect at grade. Rail crossings are
normally protected by a stop sign or a directive specifying the operating method to be followed.
CROSSOVER. Two turnouts with the track arranged to form a continuous passage between
nearby and generally parallel tracks.
CURRENT OF TRAFFIC. The movement of trains on a main track, in one direction specified
by the rules.
CUT OF CARS. A string of two or more cars coupled together.
DEFECT CARD. A card issued by a railroad acknowledging responsibility for physical damage
done to a non-owned railroad car and granting authority to bill the issuing carrier for the cost of
repairs in accordance with the Code of Interchange Rules published by the Association of
DERAIL. A safety device, attached to one rail of a siding or storage track, that will cause a
railcar to be derailed in the event it rolls free in a direction that could cause a major accident.
Used to protect main lines, sensitive loading areas, etc.
DOUBLE TRACK. Two parallel main tracks.