|Number of tracks||1|
|Track gauge||1,435 mm (4 ft 8 1⁄2 in) standard gauge|
The Trenton Cutoff (sometimes spelled Trenton Cut Off) is a 48-mile (77 km) rail corridor in the U.S. state of Pennsylvania that runs from Morrisville to Glenloch. Today used by Norfolk Southern, it consists of two rail lines: the Morrisville Line, which runs between Morrisville and Earnest (near Norristown), and the Dale Secondary between Earnest and Glenloch.
The corridor was opened by the Pennsylvania Railroad in 1892 to allow main line freight traffic to run between New York City and Harrisburg without passing through Philadelphia. The Trenton Cutoff goes through the suburbs north and west of the city. The second track (the original westbound track) was removed by Conrail around 1992.
A low-grade line, the Trenton Cutoff runs from Morrisville Yard on the Northeast Corridor to GLEN interlocking where it joins the Amtrak-owned Philadelphia to Harrisburg Main Line. Between Morrisville and Earnest, the Trenton Cutoff has active freight service. At Earnest, the Trenton Cutoff connects with the SEPTA Manayunk/Norristown Line (former Reading Railroad), with a connection to Norfolk Southern's Harrisburg Line via a bridge over the Schuylkill River west of the Norristown Transportation Center. From Earnest west to GLEN interlocking, the Trenton Cutoff is a single track in dark (unsignaled) territory. As of 2014, it sees one freight per day, carrying ArcelorMittal steel from Coatesville to Conshohocken.
Originally a two-tracked electrified rail line, the catenary wire over the tracks was dismantled by NS to provide greater overhead clearance for double-stack container trains. The high voltage transmission lines running along the Trenton Cutoff from Norristown, where the Trenton Cutoff crosses over the abandoned Pennsylvania Railroad Schuylkill Branch, to Glenloch are part of Amtrak's 25 Hz traction power system, used to power trains on the Northeast Corridor and the Keystone Corridor. For the most part, the line is grade-separated, except for two grade crossings at Bustleton Pike and County Line Road. One of PECO's power lines follows the line from Willow Grove to Langhorne.
- "Pennsylvania Railroad "Low-grade" Lines". TrainSpottingWorld. Retrieved 2015-03-14.
- "PRR Interlocking Diagrams: Philadelphia to Harrisburg Branches". The Broad Way, A Pennsylvania Railroad Home Page. Retrieved 2015-03-14.
- "Conrail Track Chart, 1991" (PDF). Multimodalways. Retrieved 2016-11-16. Compare with "Conrail Track Chart, 1993" (PDF). Multimodalways. Retrieved 2016-11-16.