- Hack (slang, US): A caboose, since it carried the crew around like a taxicab.
- Hammerhead style (slang, US): The practice of running a Diesel locomotive with its long hood forward. This has been done for a variety of reasons, such as crew safety in case of a collision. On short runs, operating the locomotive "backwards" is more economical than using a wye or turntable or operating a second locomotive. Some locomotives may have a second control stand to facilitate operation in the "reverse" direction.
- Handcar (US), A small, hand-powered railroad car used for track inspection. Pump trolley (UK).
- Harmonic rock: The condition of locomotives and cars swaying in opposite directions when traversing depressions on the roadbed. A potentially dangerous condition that can cause coupler damage, lading damage, or derailments at slower speeds.
- Head end power or HEP: A scheme whereby the locomotive engine or a separate generator provides 'hotel' power to carriages.
- Headboard: A sign attached to a locomotive to identify a named train or tour/charter, or for other special occasions.
- Headshunt (UK), Shunting neck (US): A length of track feeding a number of sidings that permits the sidings to be shunted without blocking the main line, or where two lines merge into one before ending with a buffer, to allow a run-round procedure to take place.
- Headstock: A transverse structural member located at the extreme end of a rail vehicle's underframe. The headstock supports the coupling at that end of the vehicle, and may also support buffers, in which case it may also be known as a "buffer beam".
- Heavy haul: Heavy freight operations.
- Heavy rail (US): A city-based transit rail system that runs on its own dedicated track and often underground. Subways are considered heavy rail. Refers to commuter rail and inter-city rail when used by the FRA or in other countries.
- Heavyweight (US): During the period between about 1910 and the mid nineteen thirties, most passenger cars in the US were built with three axle trucks, concrete floors, and riveted, double walled sides and often weighed 90 - 100 tons or more. Heavyweight construction was used to improve ride quality.
- Highball (US): 1. The conductor's signal for a train to depart. 2. To move at speed over the main track on a clear signal indication. Originated with the now-obsolete ball signal system, in which a ball hoisted all the way to the top of its post indicated to a train crew that the track ahead was clear.
- High Iron (slang): The mainline track.
- High rail: The upper rail in a curve or superelevation which typically experiences the higher lateral loads and greater wear.
- Hit the ground (slang): To derail
- Hogger (slang, US): A locomotive engineer.
- Hole, the: A passing siding. Inferior trains "lay over in the hole" to let superior ones pass.
- Home signal: See absolute signal.
- Hoodlebug (slang, US): A small commuter passenger train or trolley.
- Hood unit (US): A locomotive whose sides and roof are nonstructural and do not extend the full width of the locomotive. Structural strength comes from the underframe.
- Horn blocks: Plates lining the axlebox cut-outs in a locomotive frame to allow smooth vertical movement under control of the springs.
- Hotbox: An axle bearing that has become excessively hot due to friction.
- Hotbox detector: A device attached to the track which monitors passing trains for hot axles, and then reports the results via a radio transmission (US) or a circuit to the signal box (UK). (see defect detector).
- Hotel power (US): Electric power used to provide for the comfort of passengers aboard a train en-route. See "HEP" above.
- Hot rail (US): 1. Any section of track over which a train movement is imminent. The closer and/or faster the approaching train, the "hotter" the rail. 2. On some electrified railroads and rapid transit lines, the third rail which supplies power to locomotives or cars.
- Hotshot (US): A fast, long-distance train given priority on the track over other trains.
- Hudson: A steam locomotive with a 4-6-4 wheel arrangement.
- Hump: A raised section in a rail sorting yard that allows operators to use gravity to move freight railcars into the proper position within the yard when making up trains of cars (that is, humping the cars). This is faster and requires less effort than moving cars with a switching engine.
- Hunting: Swaying motion of a railway vehicle or bogie caused by the coning action on which the directional stability of an adhesion railway depends. The truck or bogie wanders from side to side between the rails, "hunting" for the optimum location based on the forces at play.
|
|