WABCOPAC BRAKES
The proprietary name for truck mounted brakes manufactured by Westinghouse Air Brake Company.

WAFER SPHERE¨ VALVE
A 6" butterfly style bottom outlet valve manufactured by Neles-Jamesbury, Inc.

WASH OUT NOZZLE
See "Bottom Washout."

WATER CAPACITY
The number of gallons of water a tank will hold.

WAY BILL
A document prepared by a transportation line at the point of origin of a shipment, showing the point of origin, destination, route, consignor, consignee, description of shipment and amount charged for the transportation services and forwarded with the shipment, or direct by mail, to the agent at the transfer point or waybill destination.

WELDING
The process of joining two members by the addition of heat and filler metal.

WHEEL
The cast or forged steel railway wheels that are semi-permanently mounted in pairs on the steel truck axles.

WHEEL BASE
The horizontal distance between centers of the first and last axles of a railway truck.

WHEEL BURN
Damage to the tank shell due to frictional contact with a rotating wheel, resulting in metal flow and/or discoloration due to frictional heat.

WHEEL FLANGE
See Flange, Wheel

WHITE METAL BLAST
See "Blast."

WOODCHIP HOPPER
Open top cars with interior slope sheets and gates used to transport woodchips.