Based on a series of 6 prototype Pioneer III cars built in 1958, the Silverliners represented the first production order of "modern" commuter MU equipment purchased by either railroad and earned their name from their unpainted stainless steel construction which contrasted with the painted carbon steel bodies of the pre-war MU fleets.

As a result, state and local government stepped in to purchase new cars that would be in turn used by the private railroads to run the required commuter operations through an entity known as the Passenger Service Improvement Corporation.

While some referred to the new vehicles as "PSIC Cars", the modern stainless steel body shells quickly defined the fleet and the name "Silverliner" was soon adopted.

[2] In 1968 the Pennsylvania Railroad was merged into the new Penn Central and although funding for the commuter rail services were being provided by the newly formed SEPTA, from 1963 until the formation of Conrail in 1976, the Silverliners were operated by and wore the livery of their respective railroads, the PRR Keystone being replaced by the Penn Central "Worms" after the merger and the Reading diamond throughout.

In late 1984 the Center City Commuter Connection opened allowing the Reading and PRR cars to mix and roam about either "side" of the system.

By 2000 the cars' age was becoming apparent with decreasing reliability and lack of ADA compliance which included the manually operated doors which were becoming a hindrance at SEPTA's increasing number of stations equipped with high level platforms.

[5] During this period an increasing number of Silverliner II cars began to be sidelined with serious mechanical problems with a few even catching fire in service.

While largely identical to the earlier Pioneer IIIs, differences included a single-arm Faiveley pantograph, a state-of-the-art propulsion system that made use of solid-state phase angle controllers coupled to mercury arc ignitron rectifiers, higher-powered motors, a higher-capacity main transformer, multi-function couplers and disc brakes.

The first group of PRR cars (201–219) were intended by be used on longer distance runs to places like Harrisburg, PA and New York City and were equipped with a bathroom on the "F" end to facilitate this.

When this change was carried out the Penn Central fitted its cars with a welded bar pilot to protect the leading wheels from debris impact.