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
Railway & Locomotive Historical Society.
Radius rod
On a steam locomotive, the small rod that transmits motion from the valve gear mechanism to the valve rod.
Steel bar that, when joined end to end, and laid in parallel, creates a fixed guideway over which the wheels of trains can roll. Consists of three parts: the head, web, and base. Standard rail length was once 39 feet, and joined together with bolts and angle bars. Modern continuous welded rail segments can be as long as 1500 feet.
Rail lubricator
Devices mounted along the rails in areas of high curvature that apply lubricant to the flanges of locomotives and cars of passing trains to reduce both flange- and rail-wear.
Name originally proposed for Amtrak (derived from "railroad" and a slang term for "passengers")
In a U.S. context, generally refers to the tracks, structures, rolling stock, and other assets that together constitute a single property.
Generally used for a railroad operating with light equipment or within a small area, as in street railway or marine railway. Also used in a business's corporate title to distinguish a corporate entity from a predecessor that operated substantially the same property under a similar name. (For example, the Duluth, Winnipeg & Pacific Railroad was succeeded by the Duluth, Winnipeg & Pacific Railway.)
Railway Express Agency
REA was the latter-day abbreviation adopted by the Railway Express Agency, owned by the private passenger railroads as an umbrella firm to ship packages, etc. on passenger trains. Metal REA signs were typically found on depots. The official name became "REA Express." It withered away as the passenger trains did and as truck and then air shipping companies grew.
Remote Control Equipment.
Rail Diesel Car. A self-propelled passenger car built by the Budd Company. The engines, which are mounted under the floor, are usually two 275- or 300-h.p. Detroit diesels driving through torque converters. Budd built 404 RDCs, in five different models, for 27 railroads and 4 foreign countries between 1949 and 1962.
Please see Railway Express Agency.
A process in which a locomotive is taken apart and put back together with new or reconditioned components, emerging from the shop as a more powerful or more efficient unit. This is done because it is cheaper to replace worn-out parts, possibly upgrading the locomotive at the same time, than to buy a whole new locomotive.
Rebuilt locomotive
A locomotive that has had all major components replaced with new or renovated ones.
A person appointed by a court to manage a corporation during a period of reorganization in an effort to avoid bankruptcy.
Management of a corporation by a receiver.
Receiving yard
The destination for arriving trains carrying cars to be sorted or classified.
The replacement of one train crew with another, either at predetermined locations along a train's route, or when the original crew has reached its maximum allowable hours on duty.
In a diesel locomotive, converts A.C. power to D.C.
Slang term for refrigerator car.
Refrigerator car
Boxcar with mechanical cooling equipment.
Regional railroad
A railroad bigger than a short line but smaller than a major railroad, usually a Class 2 railroad. Examples: Bangor & Aroostook, Ontario Northland, Florida East Coast, Iowa Interstate.
Remote power unit
A unit of motive power with traction motors but without a diesel engine. Electricity for the motors is provided by a standard locomotive with which the slug is mated. Usually used in hump, transfer, or other low-speed service. The engine-the prime mover-of a diesel locomotive can produce more electric power than its traction motors can absorb at low speeds. A slug can use this excess current to provide additional tractive force. Other terms are slug, MATE, TEBU, yard booster unit, and drone.
The rehabilitation of the finances of a business concern under procedures prescribed by federal bankruptcy legislation.
Reporting marks
A set of two, three, or four initials identifying the operator of a car.
Restricted speed
Slow operating speed that permits the engineer to stop the train within half the range of vision short of a stop signal, train, track employee, or any type of dangerous condition. Trains operating at restricted speed are never to exceed 20 mph.
A valve to retain air pressure on a freight car's brake system. Largely a thing of the past with the advent of the pressure-maintaining features of the 26L locomotive brake valve.
To remove an engine from a railroad's roster, or list of locomotives, father out of service than "stored" but possibly not yet scrapped.
Richmond, Fredericksburg & Potomac Railroad.
Ribbon rail
Rail laid in lengths of 1,500 feet or so, rather than 39-foot pieces bolted together. It does not buckle, because the track structure resists thermal expansion and contraction, and the elasticity of the steel forces dimensional changes to occur in the cross section of the rail rather than in its length. Commonly referred to as continuous welded rail (CWR).
Right of way
The track, roadbed, and property along the track owned by the railroad.
Road number
The number used by a railroad to identify a particular locomotive or unit
Road slug
A power unit with traction motors but no prime mover or generator; electricity for the motors is supplied by a connected locomotive.
Road unit
A diesel locomotive designed for getting trains over the road rather than for switching cars. A road unit has trucks that ride well at speed, gearing that keeps traction motor speed down and axle speed up, and a high-horsepower prime mover.
On real railroads, the foundation layer of earth on which the track is built.
Employee in charge of track maintenance.
Special freight vehicles similar to semi-truck trailers that can travel on highways and railroad tracks.
In the early days of dieselization, units were intended for specific duties, such as switching in the yard or getting a train over the road. The road-switcher was developed as a multi-purpose locomotive, essentially a stretched switcher on road trucks and geared for mainline speeds, often equipped with a steam generator for heating passenger cars.
Inspection of a passing train.
Rolling stock
Cars and/or locomotives.
Rotary dump car
An open-top hopper with a rotating coupler that can be unloaded by turning the car over while it is still coupled.
Rotary plow
Snowplow with a set of revolving blades that churn the snow up through an exhaust port.
Route mile
A mile of railroad without regard to the number of tracks on that line. An 85-mile-long double track railroad has 85 route-miles but 170 track miles not counting sidings, spurs, and yards.
Railway Post Office; a car for the en route sorting of mail (last used in the U.S. in 1977).
Railroad Enthusiasts, Inc.
Ruling grade
The steepest or longest grade on a given section of railroad; it determines the maximum tonnage that can be handled over the territory by a given locomotive.
Run 8
The highest notch on a diesel locomotive's throttle; "full power".
Track arrangement that allows moving an engine from one end of a line of cars to the other (n). A maneuver in which the engine is uncoupled from the train, run around the train on another track, and coupled to the other end of the train (v).
Train that is not scheduled to pick up or set out cars along its route.
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