Satellite view of Horseshoe Curve, west of Altoona, Pennsylvania. The uphill grade is downward in the photo.

Horseshoe Curve is a famous railroad curve in central Pennsylvania in the United States, built by the Pennsylvania Railroad and later used by the Penn Central, Conrail and most recently Norfolk Southern. It is located in Kittanning Gap at the summit of the Allegheny Ridge , approximately 5 miles (8 km) west of Altoona. The bend is a tight arc of approximately 220 degrees. It comprises two separate curves; on the north side, the radius measures 637 ft (194 m), tightening to 609 ft (186 m) on the south side. The curve was built in response to the difficulty of constructing a railroad through the summit of the Allegheny Mountains. It was designed by J. Edgar Thomson and opened on February 15, 1854.

The curve has been in nearly continuous operation since 1854. Originally comprising two tracks, it was widened to four tracks in 1898–1900. Conrail removed one of the tracks in 1981 and the Curve remains in this three-track configuration. It has long been a popular tourist attraction, visitable by a funicular railway running to a small park built by the PRR in 1879 at the summit of the ridge.

The curve's importance to railroad traffic in America was such that a planned Nazi attack during World War II would have blown it up. The curve was designated as a National Historic Landmark in 1966.

The curve is also an unofficial international meeting place for railfans, foamers, and trainspotters alike. The curve inspired the name of Altoona's minor league baseball team, the Altoona Curve.

See also

• Kittanning Path
• Tehachapi Loop

External links

• Railroad City: Horseshoe Curve
• Northeast Railfan: Horseshoe Curve