The

Pennsylvania Railroad The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...

's class AA1 comprised two experimental

electric locomotives An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or a supercapacitor. Locomotives with on-board fuelled prime movers, such as diesel engines or gas t ...

constructed in 1905 by the company's own

Altoona Works Altoona Works (also known as Altoona Terminal) is a large railroad industrial complex in Altoona, Pennsylvania. It was built between 1850 and 1925 by the Pennsylvania Railroad (PRR), to supply the railroad with locomotives, railroad cars and relat ...

with the assistance of Westinghouse. Intended as testbeds as the PRR began its electrification project, both locomotives remained service into the 1930s.

History

In the early 1900s, the Pennsylvania Railroad embarked on a major program to improve its access to

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

. The

New York Tunnel Extension The New York Tunnel Extension (also New York Improvement and Tunnel Extension) is a combination of railroad tunnels and approaches from New Jersey and Long Island to Pennsylvania Station (New York City), Pennsylvania Station in Midtown Manhattan ...

comprised tunnels and approaches from

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

and

Long Island Long Island is a densely populated island in the southeastern region of the U.S. state of New York (state), New York, part of the New York metropolitan area. With over 8 million people, Long Island is the most populous island in the United Sta ...

Midtown Manhattan Midtown Manhattan is the central portion of the New York City borough of Manhattan and serves as the city's primary central business district. Midtown is home to some of the city's most prominent buildings, including the Empire State Buildin ...

, leading to the PRR's massive new station,

New York Penn Station Pennsylvania Station, also known as New York Penn Station or simply Penn Station, is the main inter-city rail, intercity railroad station in New York City and the List of busiest railway stations in North America, busiest transportation facilit ...

. It was obvious that

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

s would be inappropriate for prolonged operation underground, so the PRR began experimenting with 600 V DC electrification, which had already been placed into operation elsewhere by the

Baltimore and Ohio Railroad The Baltimore and Ohio Railroad was the first common carrier railroad and the oldest railroad in the United States, with its first section opening in 1830. Merchants from Baltimore, which had benefited to some extent from the construction of ...

and the

New York, New Haven and Hartford Railroad The New York, New Haven and Hartford Railroad , commonly known as The Consolidated, or simply as the New Haven, was a railroad that operated in the New England region of the United States from 1872 to December 31, 1968. Founded by the merger of ...

. The Pennsylvania Railroad constructed the two locomotives in its

as testbeds for larger locomotives to come. Both were of B-B

wheel arrangement In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...

in the

Association of American Railroads The Association of American Railroads (AAR) is an industry trade group representing primarily the major freight Rail transport, railroads of North America (Canada, Mexico and the United States). Amtrak and some regional Commuter rail in North Am ...

classification scheme; each had two

trucks A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

, each with two axles and four wheels. The first, 10001, used direct geared traction motors. The second, 10002, was built with motors mounted in the truck frames and geared to the wheels. Later on it was given one gearless truck. Both locomotives proved unstable at speed, pounding the track with high lateral forces. A competing experimental unit, "Odd D" #10003, of

4-4-0 4-4-0 is a locomotive type with a classification that uses the Whyte notation for the classification of steam locomotives by wheel arrangement and represents the arrangement: four leading wheels on two axles (usually in a leading bogie), four po ...

wheel arrangement in

Whyte notation Whyte notation is a classification method for steam locomotives, and some internal combustion locomotives and electric locomotives, by wheel arrangement. It was devised by Frederick Methvan Whyte, and came into use in the early twentieth ce ...

or 2-B in the AAR scheme, proved much more stable. It was selected as the basis for the production model, which became the

PRR DD1 The Pennsylvania Railroad DD1 was a class of boxcab electric locomotives built by the Pennsylvania Railroad. The locomotives were developed as part of the railroad's New York Tunnel Extension, which built the original Pennsylvania Station in New ...

twin-unit A twin unit or twinset is a set of two railroad cars or locomotives which are permanently coupled and treated as if they were a single unit. A twinset of cars or coaches can also be called a twin car. In US passenger railroad parlance, twin u ...

locomotive. At low speeds in switching service, however, the locomotives were acceptable. The first, #10001, was renumbered #3950 and was sold to the (PRR subsidiary)

Long Island Rail Road The Long Island Rail Road , often abbreviated as the LIRR, is a commuter rail system in the southeastern part of the U.S. state of New York (state), New York, stretching from Manhattan to the eastern tip of Suffolk County, New York, Suffolk Co ...

in 1916. Numbered 323 on that road and nicknamed "Phoebe", the locomotive was in use until 1937 when it was

scrap Scrap consists of Recycling, recyclable materials, usually metals, left over from product manufacturing and consumption, such as parts of vehicles, building supplies, and surplus materials. Unlike waste, scrap Waste valorization, has monetary ...

ped. No. 10002, meanwhile, was renumbered #3951 and continued in service on the PRR.

Notes

References

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External links

LIRR Early Electric Engines (TrainsAreFun.com)
B-B locomotives AA1 Long Island Rail Road 600 V DC locomotives Experimental locomotives Westinghouse locomotives Electric locomotives of the United States Scrapped locomotives Standard gauge locomotives of the United States {{electric-loco-stub