The Jersey Arrow is a type of electric multiple unit (EMU) railcar developed for the Pennsylvania Railroad, and used through successive commuter operators in New Jersey, through to NJ Transit. Three models were built, but only the third model is in use today. The series is similar to SEPTA's Silverliner series, but include center doors among other differences in details. The first series of Arrows (classed MA-1A or PRR MP85E6) were built in 1968-69 by the St. Louis Car Company; 35 were built and purchased by the New Jersey Department of Transportation (NJDOT). These cars were initially numbered 100-134. These cars were built with higher capacity 3-2 seating which caused grumbling by the passengers at that time.
In 1966 the NJDOT ordered 35 PRR MP85 class MU cars from St. Louis Car for high speed service between New York and Trenton with a design based on the SEPTA/PSIC (Passenger Service Improvement Corporation) Silverliner III units then under order from St. Louis Car. The first two cars (100 and 101) were delivered in August 1968 and passenger service for the New Jersey Arrows began October 30, 1968. The body and structure (except end sills and bolsters) was all stainless steel. The stainless sheetmetal that made up the sides, ends and roof were load-carrying as part of an integral (monocoque) structure with the stainless center sill. Although these cars bear some resemblance to the Silverliner III also produced by St. Louis Car at the time, they are very different mechanically. They featured diamond-shaped twin-arm Stemmann pantographs, rounder windows, a right-side operating controls, center doors, and a different body shape. The Arrow I used Westinghouse SCR Tracpak propulsion units with 700 HP per car with four motors; while the Silverliners had GE air-cooled Ignitrons. Car 107 caught fire early in its career and was scrapped. Car 105 was also severely damaged in a collision in the East River Tunnel near New York Penn Station in 1975. It was stored in Sunnyside Yard until the mid 80s, when it was scrapped.
During 1976, 19 of the 33 surviving Arrow Is were rebuilt to be compatible with the new Arrow IIs. This involved the replacement of Symington-Wayne SW800 hook type couplers with the Wabco N2A couplers used by subsequent Arrow MUs. As they were rebuilt, they were renumbered 500-533, with car 134 being renumbered 507 to account for the loss of 107.
A further renumbering of the Arrow Is to 1200-1233 was planned, however this was never implemented as the Arrow Is were instead retired. The Arrow Is were stored as the Arrow IIIs arrived from General Electric. All cars were out of service by 1980 due to reliability issues with their Westinghouse control equipment. These problems were a result of poor wiring and frequent electrical grounds.