AAR - Association of American Railroads.

Abandonment - The permanent cessation of rail activity on a given line of railroad.

Accident - The word accident should not be used when describing a crash between a motor vehicle and a train. An "accident" is an uncontrolled event. A "crash" or a "collision" is preventable. The preferred terms are crash, collision, and incident. (See Crash.)

Active Warning Device Circuitry

  1. Constant Warning Time - A motion sensing system with the capability of measuring train speed and providing a relatively uniform warning time to public traffic at highway-rail intersections.
  2. Motion Sensor - An electronic device that senses the movement of a train within the approach to a highway-rail grade crossing. It also detects when a train ceases to move toward the crossing and will, after a specific period of time, deactivate the crossing signals, allowing vehicular traffic to traverse the crossing.
  3. Track Circuit - An electrical circuit, of which the rails of the track form a part, used to detect trains and activate warning signals.

Address - The location of a highway-rail grade crossing. There are three addressing systems that locate a highway-rail grade crossing:

  1. The local governmental street address
  2. The railroad milepost number
  3. The Federal DOT Crossing Number (See DOT Crossing Number and Milepost Number.)

Air Brakes - A system that uses compressed air to push the brake shoes onto the train wheels.

Annual Average Daily Traffic (A.A.D.T) - The annualized average 24-hour volume of vehicles at a given point or section of highway. It is normally calculated by determining the volume of vehicles during a given period, and dividing that number by the number of days in that period. Also known as a "Traffic Count".

Axle - A round metal bar that joins a pair of wheels together.



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Ballast - Small rocks that make up the base of a railroad track.

Bogie - A set of four wheels fitted under a locomotive or freight car to help it turn on curved track.

Boiler - The large metal drum on a steam locomotive, where the water is turned into steam.

Branch Line - A secondary line of a railroad. (See Main Line.)



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Cab - The part of a locomotive unit with the operating controls for the engine and seats for the train and engine crew. (See Locomotive.)

Cantilever - See under Traffic Control Devices.

Casualty - A person fatally injured, or who sustains injuries and is recorded as a personal injury in a collision/incident.

CHEMTREC - A private chemical transportation emergency center that provides information guidance when given a name of a product or chemical and the nature of the problem. (1-800-424-9300 or www.chemtrec.com)

Collision - See Crash.

Conductor - A railroad employee in charge of train or yard movement.

Consist - A document which shows the number of loads, empties, weight in tons and length in feet of a specific train. A consist shows the identifying number of each locomotive and location within that consist for a specific train.

Corridor - A designated strip of land between two locations within which rail, highway and pedestrian traffic, topography, environment and other characteristics are evaluated for transportation purposes.

Coupler - A device for joining cars to an engine and to each other to form a train.

Cowcatcher - (slang) A metal grid fitted to the front of a locomotive to nudge animals off the track (technically called the "pilot"). "Cowcatcher" is not used in the modern railroad industry.

Crash - An event occurring on a traffic way involving highway and railroad equipment that produces damage and/or injury. Other acceptable terms are "collision" and "incident".

Crossing Angle - The angle at which a railroad and a highway intersect.

Crossing Surfaces - See Highway-Rail Grade Crossing Surfaces.



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Derailment - When a locomotive or other rail cars leave the track.

Diesel-Electric Engine - A locomotive using diesel oil as the fuel to generate electricity, which in turn powers electric motors that drive the wheels.

Diesel Engine - An engine, fueled by diesel oil, used in some trains either to power the engine directly or to drive the electric motors that power the engine.

DOT - Department of Transportation.

DOT Crossing Number - (Inventory Number) A uniform national numbering system in which a unique designation is assigned to every highway-rail grade crossing in the nation. It consists of a six-digit number followed by a letter. This number should be posted at the crossing and is essential to state crossing safety programs.

Driving Wheels - The main wheels that are connected to a power supply and move a locomotive.



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Electric Engine - A locomotive powered by electricity picked up from an electric cable or third rail.

Electro-Diesel Engine - An engine that can run on both electrified and non-electrified tracks.

Engineer - See Locomotive Engineer.



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Fail-Safe Principle - Highway-rail intersection warning systems apply this principle to activate the warning system when a train is approaching the intersection, or when there are component failures or abnormal conditions in the system.

Federal-Aid Crossing Safety Improvement Program - Section 130, Title 23 U.S.C., Railway-Highway Crossing. In addition to providing monies for highway-rail grade crossing safety improvements, this program provides that each state shall conduct and systematically maintain a survey of all public crossings and identify those which may require improvements, such as: separation, relocation, warning signs and devices, and surfaces. It also requires each state to establish and implement a schedule of projects for this purpose.

Firebox - The metal box behind a steam locomotive's boiler, where the fuel is burned.

Fireman - The person on a steam locomotive who shovels coal into the firebox and keeps the boiler filled with water.

Fire Stoker - The person who keeps the fire fueled in a steam locomotive.

Flange - The extended part of a wheel that keeps it on the rail.

Flangeway - A space between the crossing surface and the inside of the rail.

Flashing Red Light Signal - See under Traffic Control Devices.

Footplate - The part of a steam locomotive on which the engineer and stoker stand.

Freight - The goods or cargo carried on a train.

Freight Car - A rail car that carries freight, or goods.



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Gauge - The distance between the two rails of a railroad track. The standard gauge in the United States is 56.5 inches.

Gate - See under Traffic Control Devices.

G.C.C.I. (Grade Crossing Collision Investigation) - A class for law enforcement officers, investigators and emergency response personnel covering the techniques and uniqueness of vehicle/train collision investigations and the related hazards. This class may be sponsored by Operation Lifesaver, a railroad company, and/or national and local police agencies.

Grade - The slope of a railroad track.

Grade Separation - A crossing of a roadway and a railroad at different elevations, such as a bridge structure carrying the highway over the railroad or vice versa.

  1. Private Crossing - An at-grade crossing where the road is privately owned, and is intended for use by the owner or by the owner's licensees and invitees. It is not generally intended for public use, and it is not maintained by a public authority. Private crossings usually are found on farms and in industrial/ commercial complexes, or they provide access to recreational and residential areas.
  2. Public Crossing - A highway-rail grade crossing where the intersecting roadway is under the jurisdiction of, and maintained by, a public authority and open to the traveling public.



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Highway - A general term for denoting a public way for purposes of travel by vehicular and/or pedestrian travel, including the entire area within the right-of-way.

Highway-Rail Grade Crossing - The general area where a highway and a railroad cross at the same level, within which are located the railroad, roadway and roadside facilities for traffic traversing that area. Also known as a "highway-rail intersection" and "railroad crossing".

Highway-Rail Grade Crossing Responsibility - The determination of need and selection of devices at a grade crossing is made by the public agency with jurisdiction. Before a new or modified grade crossing traffic control system is installed, approval is required from the appropriate agency within a given state.

Highway-Rail Grade Crossing Surfaces - The roadway material placed between and alongside the railroad tracks to allow vehicles to traverse an at-grade crossing. Crossing surface materials may be asphalt or timber, or a combination of both. Crossing surfaces may also be removable panels that are pre-engineered and premanufactured from durable materials, such as reinforced concrete, molded rubber, treated timber, and others.

Highway Traffic Signal - A power-operated traffic control device by which traffic is warned or directed to take some specific action.

Highway User - Any person using a road, street, highway or right-of-way for transportation purposes.



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Incident - See Crash.



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Lane - That part of a roadway designed for use by a single line of vehicles.

Locomotive - A self-powered unit used to move freight and/or passenger cars.

Locomotive Engineer - A railroad employee who is responsible for safely and efficiently operating an engine, engines, or engines and train. An engineer must be federally certified to operate locomotives and must have a current certificate on their person at anytime they are operating an engine.

Locomotive Event Recorder - A recording device located on all locomotives which will travel at speeds of 30 mph or more, which creates a record of speed, distance, time and other locomotive functions or events.



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Main Line - A principal line of a railroad.

Main Track - A track extending through yards and between stations that must not be occupied without authority or protection.

Manual of Uniform Traffic Control Devices (M.U.T.C.D.) - The manual approved by the Federal Highway Administration as the national standard for traffic control devices used on all public streets and highways.

Milepost Number - The railroad's addressing system for identifying a location on the tracks, measured in miles from a given point along the tracks.



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Officer on the Train - A safety program that brings local, county and state law enforcement officers into the locomotive cab to observe problems at highway-rail grade crossings and to assist enforcement of motor vehicle laws at railroad crossings.

Operation Lifesaver (OL) - A national, non-profit public awareness and education program, with a broad-based coalition of partners in federal, state, and local government agencies, private safety organizations and transportation industry, dedicated to reducing collisions, deaths and injuries at highway-rail grade crossings and railroad rights-of way.

OL Contact - Any meeting or presentation to introduce Operation Lifesaver, or to request assistance or coordinate Operation Lifesaver activities or events.

OL Presentation - Any formal presentation using the official Operation Lifesaver, Inc., Presenter Guide format to provide highway-rail grade crossing safety and/or trespass prevention information to two or more people.

OL Sponsor - Any organization, company, association or government agency that supports Operation Lifesaver through financial contributions, in-kind services, and/or personnel.

OL State Coordinator - A person designated to act as the "CEO", spokesperson, and coordinator of all activities carried out by partners and participants involved in their state Operation Lifesaver program.



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Pantograph - A metal frame on top of an electric locomotive that picks up electricity from cables hanging above the track.

Pedestrian - A person afoot, in a wheelchair, on skates, or on a skateboard.



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Rail - A rolled steel shape, commonly a T-Section, designed to be laid end to end in two parallel lines on cross ties or other suitable supports to form a track for railroad rolling stock.

Rail Bed - The layer of material spread over the formation on which the ties and track are laid. Also called ballast bed.

Railroad - A surface transportation system that operates on railroad tracks.

Railroad Police - A railroad employee who has full police powers. Also known as a "Special Agent".

Railroad Rights-of-Way - The private land, property, or interest therein, extending a given distance on each side of the railroad tracks.

Roadway - That portion of a highway improved, designated, or ordinarily used for vehicular travel.



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Sandbox - A box in which sand is stored to be fed by pipes onto the rail ahead of the driving wheels to stop them from slipping.

Siding - A track connected to the main track and used for meeting or passing trains.

Sight Distance - The distance along a railroad track from which a train might be seen by a highway user.

Spike - A large metal-type nail that fastens the rails to the wooden ties.

Spur - Auxiliary track used for delivery or storage of rail cars.

Stopping Distance - The distance required to bring a moving train or motor vehicle to a complete stop.



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Tender - A car attached to a steam locomotive, that carries the locomotive's water and fuel, either wood or coal.

Third Rail - An electrical conductor for transmitting electricity to a locomotive on third-rail electrified tracks.

Tie - In track construction, the cross members to which the rails are attached.

Traffic Control Devices - All signs, signals, markings, islands, and other devices used to regulate, warn, or guide traffic, placed on, over, or adjacent to a street, highway, road, pedestrian facility, or bicycle path by authority of a public body or official having jurisdiction. Devices that are located at a highway-rail grade crossing can be "Active" and/or "Passive" warning devices.

1. Active Warning Devices:

  1. Bell - A device which, when activated, provides an audible warning for pedestrians and bicyclists, which may be used with a flashing light signal.
  2. Cantilever - A structure, which may have flashing light signals, extending over one or more lanes of vehicular traffic.
  3. Flashing Red Light Signal - A device installed on a standard mast or cantilever which, when activated, displays red lights flashing alternately. It indicates the approach of a train and requires a complete stop by the highway user.
  4. Gate - An extended arm that lowers to restrict vehicular and pedestrian traffic from crossing the railroad tracks.

2. Passive Warning Devices:

  1. "Advance Warning" Sign - A round yellow warning sign with a black "X" and "R-R", located alongside the highway in advance of the crossing. It advises the motor vehicle operator of a crossing ahead. It means, "slow down, look, listen, and be prepared to stop if a train is approaching."
  2. Crossbuck - A white regulatory, X-shaped sign with the words, "Railroad Crossing" in black lettering, located alongside the highway at the railroad tracks. This sign is considered the same as a "Yield Sign". All motor vehicles should "Yield" to trains. At multiple track crossings, a sign indicating the number of tracks will be on the post below the crossbuck.
  3. "Do Not Stop On Tracks" Sign - A black and white regulatory sign placed at a crossing when an engineering study or experience determines there is a high potential for vehicles stopping on the tracks.
  4. "Exempt" Sign - A sign placed in advance and at a crossing authorized by law or regulation to inform placarded hazardous materials vehicles, buses and other highway users that a stop is not required, except when a signal, train crew member or a uniformed police officer indicates that a train, locomotive, or other railroad equipment is approaching the crossing.
  5. "Parallel Track" Sign - A diamond-shaped yellow advance warning sign located on roadways parallel to the railroad track, indicating the road ahead will cross the tracks. The purpose of these signs is to warn motorists making a turn that there is a highway-rail grade crossing immediately after the turn.
  6. Pavement Markings - The white lines and letters ("R X R") set into the surface of, or applied to or attached to, the pavement in advance of the crossing which is for the purpose of advising, warning or guiding traffic.
  7. Stop Sign - A red regulatory stop sign with white lettering intended for use where motor vehicle traffic is required to stop. This sign may be added to the crossing, requiring all vehicles to come to a complete stop before crossing the railroad tracks.
  8. "Tracks Out Of Service" Sign - A sign for use at a crossing in lieu of the crossbuck when a railroad track has been abandoned or its use discontinued.
  9. Yield Sign - The yield sign assigns right-of-way. Vehicles controlled by a yield sign need to avoid interference with other vehicles, including trains, which are given the right-of-way.

Traffic Sign - An official device that gives a specific message, either by words or symbols, to the public. (See Traffic Control Devices.)

Traffic Signal - See Highway Traffic Signal.

Train - One or more engines coupled with or without rail cars.

Train Detection Systems - See Active Warning Device Circuitry.

Trespasser - Any person who is on railroad property used in railroad operation and whose presence is prohibited, forbidden, or unlawful. A person on a highway-rail grade crossing is not to be classified as a trespasser unless the crossing is equipped with gates, or other similar barriers that were closed when the person went on the crossing, or unless the person attempted to pass over, under, or between cars or locomotives occupying the crossing.



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Vehicle - Every device in, upon, or by which any person or property may be transported or drawn upon a highway, except trains.



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Warrant - Describes the conditions considered by a highway engineer to determine the need for various traffic control devices.



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About Operation Lifesaver

Operation Lifesaver is a nonprofit public safety education and awareness organization dedicated to reducing collisions, fatalities and injuries at highway-rail crossings and trespassing on or near railroad tracks. Our team consists of nationwide network of volunteers who work to educate people about rail safety, state coordinators who lead the efforts in states across the U.S. and a national office in Washington, D.C., that supports state programs, develops education materials, and creates public awareness campaigns for audiences of all ages. 


National Office

Operation Lifesaver, Inc.
425 Third Street SW, Suite 915
Washington, D.C. 20024

Fax: 703-519-8267
Email : [email protected]

Media Inquiries: [email protected]

Transit Inquiries: [email protected]

Our Staff