HAND BRAKE
A device mounted on railway cars and locomotives to provide a means for applying brakes manually without air pressure. Common types include vertical wheel, horizontal wheel and lever type, so named because of the configuration or orientation of their operating handles.

HAND BRAKE CHAIN
Forms part of the connection between the handbrake shaft and the brake levers.

HAND BRAKE WHEEL
The steel handwheel attached to the hand brake shaft to provide a means for manually applying the brakes.

HAND RAIL
A bar or rail to be grasped with the hand on rail cars for safety purposes.

HAND RAIL POST
The vertical structural member that holds a handrail at the desired height.

HANDHOLD
Round steel bar of 5/8" minimum diameter, formed with a means for mechanical attachment to a car side, end or roof, to provide a secure place for crew or other operating personnel to hold on to equipment. Handholds are considered "safety appliances" by the FRA, and as such, are subject to very strict regulations with respect to placement and clearances. Also known as "grab irons."

HATCH
The opening through which products are loaded in covered hopper cars.

HATCH COVER
The hinged door that closes and seals a hatch on the roof of a covered hopper car.

HAZARDOUS MATERIAL
When used with respect to lading in transportation vehicles, a term identifying the lading as subject to specific safety requirements set forth by the Department of Transportation and/or the Interstate Commerce Commission. Examples of hazardous materials are explosives, poisons, flammable liquids, corrosive substances, and oxidizing or radioactive materials. Also refer to Bureau of Explosives Tariff No. BOE-6000 (Latest Revision), Sect. 172.101.

HD
Acronym for "Hot Dog" which refers to a stub sill design tank car (without a continuous center sill).

HEAD PLATE
Refers to the flat plate of metal that will subsequently be formed into a tank head.\

HEAD PRESS
Within Union Tank Car, the largest machine (12,000 ton hydraulic press), located at Plant No. 1 in East Chicago, IN, that is used to cold form tank and jacket heads.

HEAD SHIELD
A supplemental heavy steel plate required by federal regulation on the ends of some hazardous commodity tank cars to lessen the chances of tank head puncture by the coupler of an adjacent car in the event of excessive end impact or derailment.

HEAD SHOE
The reinforcement structure between the draft sill and tank head at each end of a tank car.

HEADER
A lateral or circumferential heater coil that connects two (2) or more parallel longitudinal heater coil runs.

HEADER SYSTEM
A tank car heater arrangement generally consisting of (4) or more parallel longitudinal heater coil runs connected together at each end of the tank by headers. Normally used only with steam.

HEATER COILS
The half oval heat chamber sections generally running the length of the tank which are welded to the exterior of the tank.

HEATER PIPES
The 2 inch diameter pipe sections that generally run the length of the tank and which are mounted to brackets inside of the tank.

HEATER RUNS
One, generally straight continuous longitudinal section of heater coil or heater pipe.

HEAVY REPAIRS
As reported to the Association of American Railroads, repairs to revenue freight cars requiring over 20 man-hours.

HELD FOR ORDERS
Cars in repair facilities waiting on authorization to proceed with repairs.

HELICAL SPRING
See "Coil Spring."

HOME CAR
From a railroad perspective; a car on the tracks of its owner.

HOPPER CAR
A freight car, with either a covered or open top, designed to carry dry bulk commodities such as plastic pellets, grain, or coal. The bottom of the car generally consists of a series of slope sided hoppers with bottom outlet gates.

HOPPER DOOR
See "Gate" (Discharge).

HOT DOG
See "HD."

HUCK¨ BOLT
A mechanical fastener similar to a nut and bolt, except the nut is replaced by a collar that is permanently deformed into the grooves on the bolt at application.

HUMP
In a railroad classification yard, the hill (or hump) that freight cars are rolled down and then diverted to one of a number of tracks for makeup into individual trains.

HUMP YARD
A railroad classification yard in which the classification of cars is accomplish by pushing them over a summit, known as a "hump," beyond which they run by gravity.

HYDROTEST
The water pressure test that each tank is subjected to when built and at other specific times during its life, as specified by the AAR.