The Horseshoe Curve is a three-track railroad curve on Norfolk Southern Railway's Pittsburgh Line in Blair County, Pennsylvania. The curve is roughly 2,375 feet (700 m) long and 1,300 feet (400 m) in diameter. Completed in 1854 by the Pennsylvania Railroad as a way to reduce the westbound grade to the summit of the Allegheny Mountains, it replaced the time-consuming Allegheny Portage Railroad, which was the only other route across the mountains for large vehicles. The curve was later owned and used by three Pennsylvania Railroad successors: Penn Central, Conrail, and Norfolk Southern.
The Pennsylvania Railroad K4 was a class of 425 4-6-2 steam locomotives built between 1914 and 1928 for the PRR, where they served as the primary main line passenger steam locomotives on the entire PRR system until late 1957.
The Pennsylvania Railroad's class B6 was its most successful class of switcher locomotive, or as the PRR termed them "shifter". The PRR preferred the 0-6-0 wheel arrangement for larger switchers, whereas on other railroads the 0-8-0 gained preference. The PRR generally used 2-8-0s when larger power was required.
The New York Tunnel Extension is a combination of railroad tunnels and approaches from New Jersey and Long Island to Pennsylvania Station in Midtown Manhattan.
The Pennsylvania Railroad's class O1 comprised eight experimental boxcab electric locomotives built in 1930 and 1931. They were built in preparation for the New York to Washington Electrification project. They had the wheel arrangement classified as 4-4-4 in the Whyte notation. Although successful, they were not powerful enough for the railroad's increasingly heavy trains. For production, the PRR chose to concentrate on the P5 class, effectively an enlarged and more powerful version of the O1 with an additional pair of driving wheels.
The Pennsylvania Railroad's class DD2 was a single prototype electric locomotive never placed into series production. It was intended as an improved and simplified GG1 for use on the planned, but never built, extension of the PRR's electrification west of Harrisburg, Pennsylvania. The one locomotive produced was numbered #5800 and used in regular Baltimore tunnel helper service until it was scrapped in September 1962.
Pennsylvania Railroad class E2b comprised six experimental B-B electric locomotives built for the railroad by General Electric.
The Pennsylvania Railroad's class L5 were the railroad's second generation of production electric locomotives after the DD1, and the last to use a jackshaft and side rods to drive the wheels. The L5 was a single-unit locomotive instead of the twin-unit DD1. The wheel arrangement in Whyte notation was 2-4-4-2, or 1-B-B-1 in the AAR scheme. Twenty five were built in 4 distinct subclasses. The lead unit of the class was equipped for AC operation with an overhead pantograph, while the other 24 were third rail DC units to work on the existing PRR third rail electrification in the New York area.
The Pennsylvania Railroad's class B1 comprised 42 electric switcher locomotives built between 1926 and 1935. They were of 0-6-0 wheel arrangement in the Whyte notation with 700 horsepower. As built, the first 28 locomotives in the 1926 order formed semi-permanently coupled pairs grouped in three classes.
The Pennsylvania Railroad's class AA1 comprised two experimental electric locomotives constructed in 1905 by the company's own Altoona Works with the assistance of Westinghouse. Intended as testbeds as the PRR began its electrification project, both locomotives remained service into the 1930s.
Pennsylvania Railroad's Odd D #10003 was an experimental electric locomotive built in 1907 by Baldwin and Westinghouse. It had a 4-4-0 wheel arrangement in the Whyte notation, or 2-B in the AAR scheme. On the PRR, class D was assigned to 4-4-0 locomotives. Production classes of locomotive were assigned a number after the letter, but one-off locomotives were simply designated "Odd".
Class D16 on the Pennsylvania Railroad was their final development of the 4-4-0 "American" type of steam locomotive. A total of 429 of these locomotives were built at the PRR's Juniata Shops, spread across five subclasses; some had 80 in (2,030 mm) diameter driving wheels for service in level territory, while others had 68 in (1,730 mm) drivers for mountainous terrain. In the pre-1895 scheme, these locomotives were second class L.
The PRR class D14 was a 4-4-0 steam locomotive built for the Pennsylvania Railroad. They were originally designated class P in the PRR's pre-1895 classification scheme. Twenty-two locomotives were built at the PRR's Altoona Works ; six in 1893 with 78-inch (1,981 mm) driving wheels, and sixteen in 1894 with 80-inch (2,032 mm) drivers, classified D14a. Later, all sixteen class D14a were rebuilt to class D14b with 68-inch (1,727 mm) drivers for secondary service after they were replaced in top-flight express service, while three of the six class D14 were similarly rebuilt to class D14c.
Class D6 on the Pennsylvania Railroad was a class of 4-4-0 steam locomotive. Nineteen were built by the PRR's Altoona Works between 1881 and 1883. They were equipped with 78-inch (1,981 mm) drivers. Seven were later converted to 72-inch (1,829 mm) drivers and classified D6a.
Class D7 (formerly Class A (anthracite), pre-1895) on the Pennsylvania Railroad was a class of 4-4-0 steam locomotive. Fifty-eight were built by the PRR's Altoona Works (now owned by Norfolk Southern) between 1882–1891 with 68 in (1.73 m) drivers, while sixty-one of class D7a were constructed with 62 in (1.57 m) drivers.
The Pennsylvania Railroad's steam locomotive class D1 comprised thirteen 4-4-0 locomotives for express passenger service, constructed at the railroad's own Altoona Works during 1868–1872. They were the first standardized class of locomotives on the railroad and shared many parts with other standard classes.
The Pennsylvania Railroad's MP54 was a class of electric multiple unit railcars. The class was initially constructed as an unpowered, locomotive hauled coach for suburban operations, but were designed to be rebuilt into self-propelled units as electrification plans were realized. The first of these self-propelled cars were placed in service with the PRR subsidiary Long Island Rail Road with DC propulsion in 1908 and soon spread to the Philadelphia-based network of low frequency AC electrified suburban lines in 1915. Eventually the cars came to be used throughout the railroad's electrified network from Washington, D.C. to New York City and Harrisburg, Pennsylvania.
The Pennsylvania Railroad G5 is a class of 4-6-0 steam locomotives built by the PRR's Juniata Shops in the mid-late 1920s. It was designed for passenger trains, particularly on commuter lines, and became a fixture on suburban railroads until the mid-1950s.
PRR 460, nicknamed the "Lindbergh Engine", is a preserved E6s class 4-4-2 "Atlantic" type steam locomotive now located in the Railroad Museum of Pennsylvania, outside of Strasburg, Pennsylvania in the United States. It was built in 1914 and became famous after racing an aircraft to New York City carrying newsreels of Charles Lindbergh's return to the United States after his transatlantic flight in 1927. In the late 1930s, No. 460 was operated by the Long Island Rail Road, and by the Pennsylvania-Reading Seashore Lines in the early 1950s, before being retired in 1953. No. 460 is the only surviving locomotive of its class and was listed on the U.S. National Register of Historic Places in 1979. From 2010 to 2016, No. 460 underwent cosmetic restoration at the Railroad Museum of Pennsylvania.
The Pennsylvania Railroad's class K29s comprised a single experimental 4-6-2 "Pacific" type steam locomotive. Constructed by Alco-Schenectady, it was given road number 3395. Although only one demonstrator was constructed, the K29s would become the basis for the highly successful K4s Pacifics and L1s Mikados. The lone example spent most of its life on the PRR's Pittsburgh division main line and was retired around 1929.
