Railroading Glossary
The following glossary is arranged alphabetically with each term catalogued by first letter. Select a letter below to begin.
A | B | C | D | E | F | G | H | I | J | K | L | M
N | O | P | Q | R | S | T | U | V | W | X | Y | Z
ICC
Interstate Commerce Commission. The agency of the federal government that carried out the provisions of the Interstate Commerce Act and other federal laws regulating interstate transportation. The agency went out of existence at the end of 1995, and some of its functions were taken over by the Surface Transportation Board of the Department of Transportation.
I-GN
International-Great Northern. Acquired by Missouri Pacific interests in 1924, its main lines were Longview-Laredo, Palestine-Houston, and Spring-Fort Worth, all in Texas
In the hole
On a siding (usually to allow another train to pass).
Incentive per diem
To alleviate a shortage of boxcars in the mid-1970s, the railroad industry encouraged the railroads to put new cars into service by offering an incentive payment-basically almost double the daily rental for new boxcars in good condition. Investors teamed up with short lines to take advantage of incentive payments, accounting regulations, and tax laws; short line box cars blossomed forth. Then the recession of 1978 hit, followed by truck deregulation. The boxcars were soon idle; eventually many of them were sold to other railroads.
Incorporate
To form into a corporation recognized by law as an entity.
Independent brake
Valve that allows the engineer to control the air brakes on a locomotive or multiple-unit grouping of locomotives independently of the train brakes.
Industrial locomotive
A small diesel unit intended for switching service on an industrial railroad. The engine can be gasoline or diesel; transmission can be mechanical or hydraulic rather than electric.
Industrial railroad
A railroad owned and operated by an industry to move cars within a factory, plant, or mill and to and from a common carrier interchange. Industrial railroads are usually not common carriers.
Initial air test
Before leaving a terminal, a train's engineer tests the air brake system to determine that it is functioning properly
Injector
Device for adding water to a steam locomotive boiler.
Inline
Arrangement of the cylinders of an engine in a single row; V-type engines have two rows of cylinders angled away from each other, all driving the same crankshaft.
Intake stroke
The first piston stroke in a four-cycle diesel engine. The piston, upon descending into the cylinder, draws in air for combustion through the open intake valves in the cylinder head.
Interchange
(noun) Junction of two railroads where cars are transferred from one road to another. (verb) The act of exchanging cars between two railroads.
Interchange track
Track used to exchange cars between two railroads.
Intercity passenger service
As distinguished from commuter service, the passengers don't make the trip every day, tickets are for single trips, and the luggage contains clothing, not the newspaper or work to do at home. Intercity passenger trains usually include such amenities as sleeping cars and food service.
Interlocking
An arrangement of signals and switches connected, or "interlocked", in a way that their operations must succeed each other in a predetermined order, so that conflicting routes are impossible to set up. Specific interlockings are sometimes identified as "controlled points".
Intermodal
Refers to activities involving more than one mode of transportation. With respect to freight traffic, it is most often used for the carriage of highway trailers (TOFC) or containers on flat cars (COFC). For passenger travel, it relates to the coordination of rail, bus, air, and other modes of transportation (for which the term "multimodal" is sometimes used).
Interstate Commerce Commission (ICC)
The agency of the federal government that carried out the provisions of the Interstate Commerce Act and other federal laws regulating interstate transportation. The agency went out of existence at the end of 1995, and some of its functions were taken over by the Surface Transportation Board of the Department of Transportation.
Interurban
An electric railroad running between cities, often of lighter construction than "steam" railroads and often operating in the streets of cities and towns instead of on a private right of way. Interurbans had their rise and fall during the first four decades of the twentieth century. Light rail systems could be considered the modern heirs to the interurban.
Inverter
In a diesel locomotive, converts D.C. power back to A.C. for use in the traction motors.
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