This project consisted of a reconstructed Beechview-South Hills Village line supplemented by an order of 55 Siemens SD-400 light rail cars.

However, this project would only reconstruct roughly fifty-five percent of the existing system, with the Overbrook-Library and Drake lines earmarked in the "Stage II" plan, to be rebuilt at a later date as funding became available.

These four, affectionately referred to as "Super 17's" by many, received the same mechanical and electrical improvements, seats, body work, and paint scheme as the remaining twelve, but retained several of their 1949 attributes, including original interior and exterior lighting, all-steel body panels, and operator's controls, as well as retaining their original numbers.

[3] The 4000 series was intended as an interim solution for the Authority's unrebuilt lines, which could not accommodate the newer, heavier railcars.

As a result, all major stations on portions of the system that were shared by PCC's and LRV's (these being South Hills Village, Washington Junction, Castle Shannon, South Hills Junction, and all stops north of the Mount Washington Transit Tunnel) had both high and low platforms to accommodate both types of cars.

In 1993, the Overbrook Line was shut down between Castle Shannon and South Hills Junction due to the deteriorated conditions of the track, bridges, walls, and other infrastructure.