The EMD DE30AC and EMD DM30AC are 46 locomotives built in 1997-1998 by Electro-Motive Division in the Super Steel Plant in Schenectady NY for the Long Island Rail Road

Long Island Rail Road

The Long Island Rail Road or LIRR is a commuter rail system serving the length of Long Island, New York. It is the busiest commuter railroad in North America, serving about 81.5 million passengers each year. Established in 1834 and having operated continuously since then, it is the oldest US...

 of the Metropolitan Transportation Authority (MTA)

Metropolitan Transportation Authority (New York)

The Metropolitan Transportation Authority of the State of New York is a public benefit corporation responsible for public transportation in the U.S...

 in New York.

Details and usage

The DE30AC and DM30AC locomotives replaced aging GP38s, Alco

American Locomotive Company

The American Locomotive Company, often shortened to ALCO or Alco , was a builder of railroad locomotives in the United States.-Early history:...

 FA1/FA2s, F7As and F9As, and MP15AC

EMD MP15AC

The EMD MP15AC is a 1,500 hp diesel switcher/road-switcher locomotive built by General Motors' Electro-Motive Division between August 1975 and August 1984. 246 examples were built, including 25 for export to Mexico, and four built in Canada...

 and SW1001

EMD SW1001

The EMD SW1001 was a diesel locomotive for industrial switching service built by General Motors' Electro-Motive Division between September 1968 and June 1986...

 locomotives, with GP38s used to push and pull

Push-pull train

Push–pull is a mode of operation for locomotive-hauled trains allowing them to be driven from either end.A push–pull train has a locomotive at one end of the train, connected via some form of remote control, such as multiple-unit train control, to a vehicle equipped with a control cab at the other...

 diesel trains and other locomotives used to provide HEP

Head end power

Head end power or electric train supply is a rail transport term for the electrical power distribution system on a passenger train. The power source, usually a locomotive at the front or “head” of a train or a generator car, generates all the electricity used for lighting, electrical and other...

 for the trains. The bodies of the DE30AC and the DM30AC are similar; the difference is the ability of the DM30AC to use electric third rail while the diesel engine is off, enabling the locomotive to use the East River Tunnels

East River Tunnels

The East River Tunnels are 4 single-track railroad tunnels that extend from the eastern end of Pennsylvania Station under 32nd and 33rd Streets in Manhattan and cross the East River to Long Island City in Queens. The tracks carry Long Island Rail Road and Amtrak trains travelling to and from Penn...

 into New York Penn Station

Pennsylvania Station (New York City)

Pennsylvania Station—commonly known as Penn Station—is the major intercity train station and a major commuter rail hub in New York City. It is one of the busiest rail stations in the world, and a hub for inbound and outbound railroad traffic in New York City. The New York City Subway system also...

. DM30ACs have third rail

Third rail

A third rail is a method of providing electric power to a railway train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost...

 contact shoes, permitting direct service from non-electrified lines in eastern Long Island via the western electrified main lines all the way to Penn Station. A few such trains a day run on the Port Jefferson, Oyster Bay, and Montauk Branches. The engines' naming scheme: DM = Dual Mode, DE = Diesel Engine, 30 = 3000 hp

Horsepower

Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...

, AC = Alternating Current traction motors.

Single engines generally run with 6 cars or less and are placed on the East (Montauk) end of the train, although some single engine services run with up to 8 cars. Generally two engines are used when there are 8 or more cars. Of the original 46 locomotives, 45 are still in use: #503 (DM30AC) was damaged in an accident at Huntington on October 23, 2000, when it hit a shopping cart on the tracks, which shorted out the third rail

Third rail

A third rail is a method of providing electric power to a railway train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost...

and caused a fire. It currently sits in the LIRR's Morris Park yard and has been stripped for spare parts to maintain the remainder of the fleet.