Glossary & Acronyms


Assistant General Manager

Arcing Insulator

An insulator along the third rail that may be giving off sparks or smoke

Articulated Buses

Extra-long buses with two connected passenger compartments. The rear body section is connected to the main body by a joint mechanism that allows the vehicles to bend when in operation for sharp turns and curves yet maintain a continuous interior.

At Grade

Track work constructed at the approximate level of the adjacent ground surface, rather than the elevated or subway parts of the system


Washington Metropolitan Area Transit Authority


See Brakes in Emergency


Term used to refer to the Bladensburg Metrobus facility, which serves as a major maintenance/repair, washing, and storage facility. It is located along Bladensburg Road near New York Avenue.


An area below the tracks that blows air up to the train in an effort to keep it free of dust and other particles

Bulkhead Door

The train door on the end of the car that is used for emergency passage from car to car


Bus Operations Communication Center

Brakes in Emergency

When the breaking mechanism on a rail car indicates that the brakes on the car need to be serviced, the train automatically brakes in a safe position/location on a track so that the brakes do not fail. Brakes in Emergency (BIE) is the actual application of the emergency braking system. When there is a BIE, the train cannot move.


Breda Costruzioni Ferroviarie; the name of an Italian manufacturer of rail cars

Bumpy Tiles

Tiles with raised domes that are located along the edge of the platform to provide a tactile method of alerting passengers that they are near the edge


Local bus service operated by the Prince George's County (MD) Department of Transportation


The compartment of a rail car where the operator works and where the rail car's controls are located


Construcciones Y Auxiliar de Ferrocarriles is the name of a Madrid (Spain)-based manufacturer of rail cars


The roof-type structure above Metrorail station entrances or above bus stations/terminals used to protect the entryway or customers from inclement weather


A narrow, often elevated walkway, as on the sides of a bridge

Central Control

See Rail Operations Central Control


Chief Executive Officer

Chain Marker

A distance of 100 feet indicated by a survey marker along the tracks identifying the distance in multiples of 100 feet to the middle of the Metro Center platform


Compressed Natural Gas

Code Red Day

When the air quality in the Washington Metropolitan Area is deemed to be very poor, the Metropolitan Washington Council of Governments (MWCOG) declares "code red days." On "code red days," Metrobus fares are waived on many Metrobus routes in an effort to encourage individuals to use public transportation instead of automobiles so as not to contribute to the poor air quality.


Council of Governments for the Washington Metropolitan Area

Commuter Rail

An electronic- or diesel-propelled railway for urban passenger train service consisting of local short-distance travel operating between a central city and adjacent suburbs


A mechanical device on each end of a rail car that is used to connect one car to another


The insulated cover above (and in some cases, behind) the third rail to prevent inadvertent contact with the rail and to minimize snow and ice accumulation on it. The coverboard also serves as a third rail locator, especially in yards, when the level of snow is above the third rail.

Cross Tie

One of the beams, usually made of wood, that is laid across a railroad bed to secure the rails


A passenger or patron who rides Metro or inquires about service


The local bus service provided by the Alexandria (VA) Transit Company


A non-revenue vehicle marked as "not in service"


The unintentional removal of one or more train wheels from the running rail


Diesel fuel


Deputy General Manager


The lights located along the platform edge that flash to indicate an approaching or departing train

Emergency Door

The rail car's center door equipped with a self-evacuation mechanism. Bulkhead doors at either end of the rail cars are also available for emergency-only exits.

Fairfax Connector

Fairfax County (VA) bus service


The revenue paid from a passenger to receive transit services


The receptical used to collect the customer fees for transit services


The currency purchased by customers that is used to travel on the Metrorail system


The machine at the entrance to passenger stations that records information onto, and collects fare from, the farecard as a patron enters and exits the system

Fare Evasion

When an individual uses transit or attempts to do so without paying the posted fare

Fare Vendor

The farecard vending machines at the entrance to a station


All of the vehicles that are owned or operated by a transit authority


Federal Transit Administration

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Gap Train

A train stored on a pocket track for possible insertion into a gap in the schedule if another train must be removed from service or if additional service is required


General Manager

Grade Crossings

An intersection of highway roads, railroad tracks or dedicated transit rail tracks that run either parallel to or across mixed traffic situations


The time interval between vehicles moving in the same direction on a particular route

Heavy Rail

A high-speed transit mode that is an electric railway with the capacity for a high volume of traffic

Heavy Rail Passenger Cars

Rail cars operated with electric power configured for passenger traffic


The protective covering along the third rail


Infrastructure Renewal Program

In-fill Station

A Metrorail station that is built between two existing stations after the stations on either side of it are already in use

In revenue

A train or bus that is being used to service paying customers; it is being used to generate revenue.


The part of the railroad where tracks can cross each other or change to direct trains along different routes. The interlocking itself is an arrangement of signals and signal appliances that permit train movements over controlled routes only if safe conditions exist.


Jackson Graham Building, the main headquarters for Metro


A term referring to the Judiciary Square Metrorail station


An unauthorized person on the tracks


A location where train routes converge and diverge

Kicker rail

A short third rail section


The octagonal structure near a rail station entrance that serves as the station manager's office/booth and the hub of communications for a Metrorail station

Light Rail

A means of transit that is an electric railway with a light capacity compared to heavy rail


The route that a vehicle takes to get to its destination, usually designated as a number for a bus route or a color for a rail route

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Maryland Area Regional Commuter Train Service

Married pair

Two transit rail cars that are semi-permanently coupled to each other and that share certain common equipment. Metrorail trains only operate trains with an even number of cars because it operates married pairs.


Washington Metropolitan Area Transit Authority


Paratransit service that Metro provides for people with disabilities who are certified eligible to receive this service because they are unable to access Metrorail, Metrobus or other fixed-transit services


The area of a Metrorail station that is near the entrance level that contains the faregate, fare vendors, and kiosk


Maintenance Operations Center, the facility from which all Metrorail maintenance activities are coordinated and monitored


Maryland Transportation Administration


The train operator's emergency brake control


Metro Transit Police Department


Metropolitan Washington Council of Governments


An electronic, real-time, information display system that tells customers where a bus is along the route and when it will arrive at a designated bus stop. This real-time information is accessible through Internet-connected devices.

Non-revenue hours

The hours when passenger service is not operated

Non-revenue train

Any train in test, maintenance, emergency or inspection service, which may not be used by the public


See Rail Operations Central Control


Transit systems operated by the Potomac and Rappahannock Transportation Commission (PRTC)


Individuals who are at the control of a rail car or who drive a bus: a bus operator or a rail operator

Passenger Information Display Signs

Electronic signs that provide information on the next train or bus to passengers on the Metrorail system or passengers along a NextBus bus route


A paying customer

Peak Hours

Those periods on weekdays (excluding observed holidays) normally associated with morning and evening rush hours


See Passenger Information Display Signs


The part of a Metrorail station that is on either side of the track bed where passengers wait for trains to arrive


The point where trains enter and exit tunnels

Potomac Rappahannock Transportation Commission

The authority in charge of operating OmniRide and Omnilink in Virginia

Rail Operations Central Control

The facility in the Metro headquarters building from which train control and supervision is accomplished for the entire transit system


The process of renovating a rail car, train or bus to original specifications through a rebuilding process that may include new components, mechanical systems, and interior


Money paid in fares

Revenue Hours

The hours when revenue trains or buses are in service

Revenue Service

The time when a rail car or bus is available to the paying public

Revenue Vehicle

A rail car or bus that is used by paying customers

The RideGuide

The service provided by Metro that informs customers of the various routes they can take to get to their desired destinations

Ride On

The Montgomery County (MD) local bus system


Rohr Corporation, a manufacturer of rail cars


The regular path or direction that a bus or train takes to get to different locations

Running rails

The two rails on which the wheels of trains travel

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S-1 Guards

Protective devices along the rear passenger-door side of buses that serve to push objects away from the rear door-side tire of a bus. They help prevent the rear wheel from running over objects that may be on the ground.


System Access and Capacity Program


System Expansion Program

Single track

The operation using only one main track for trains traveling in both directions by alternating the direction of traffic when the track is vacant

SmarTrip® Card

A permanent, rechargeable plastic farecard, like a credit card, which is embedded with a special computer chip that keeps track of the value of the card

Smoldering Insulator

An insulator along the third rail that may be giving off smoke

Station Manager

The Metro employee who oversees activity in a Metrorail station and serves as the head Metrorail official in a station. The Station Manager's Office is the kiosk located near the faregates.

Station Overrun

When a Metrorail train arrives at a platform, but the lead car in the train passes the platform


Transportation Association of Greater Springfield

Terminal Station

The last stop along a Metrorail line or bus route

Third Rail

The high voltage rail bar along the track that carries electrical energy to run the trains on that track. The third rail voltage is approximately 750 volts. It is also sometimes referred to as a propulsion rail or contact rail.

Train Operator

The qualified Metro employee aboard a rail vehicle who has direct and immediate control of the vehicle

Truncated Domes

See Bumpy Tiles


The underground passageway used by Metrorail cars


United States Department of Transportation


The underground Metrorail station's main cavity bordered by the interior walls between the station and the external rock-bed


Virginia Railway Express


Washington Metropolitan Area Transit Authority

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