The Knoxville Incline was a broad gaugeinclined railway that ran between Pittsburgh'sSouth Side and Allentown neighborhoods. The incline was constructed in 1890 and had a track gauge of 9 feet (2,700 mm). The charter was in planning as of January 1890, with a target filing date of February 8 of that year, and was originally to be called the Arlington Avenue Inclined Plane. The last day of service was December 3, 1960. It was demolished in 1960. It was designed by John H. McRoberts, with a length of 2644 feet. The Knoxville Incline briefly controlled the Pittsburgh, Knoxville & St. Clair Electric Railroad, while itself being later controlled by Pittsburgh Railways. During its operation, the incline ferried people and freight between the South Side and Knoxville. The Knoxville Incline and the nearby Mount Oliver Incline enabled the development of land in Allentown and surrounding communities on the hilltop. Like the Nunnery Hill Incline, the Knoxville Incline featured a curve, an unusual engineering feat for an incline.
On October 7, 1953 a boy, Alan Schiller, hanging from a car was killed. While it is commonly reported that Pittsburgh inclines recorded no fatalities, this, along with an incident on the St. Clair Incline, provide the only blemishes on the safety record of inclines in Pittsburgh. None of the fatalities occurred with paying passengers who had not jumped from cars.