The Pittsburgh and Lake Erie Railroad (P≤ reporting mark PLE), also known as the "Little Giant", was formed on May 11, 1875.

[1] This was largely because the P&LE served the steel mills of the greater Pittsburgh area, which consumed and shipped vast amounts of materials.

This provided a means of transportation from the steel centers of Pittsburgh to the Great Lakes and St. Lawrence Seaway area.

The original line ran between Youngstown, Ohio (at Haselton) and 24th Street in Pittsburgh, Pennsylvania near the Jones and Laughlin Iron Works, opened in 1879.

The P&LE's passenger terminal in Pittsburgh was on the south bank of the Monongahela River, at the foot of the Smithfield Street Bridge.

The original line continued east past that station for a little over two miles (3.2 km) (listed in Youghiogheny Branch table below) to near 24th Street in the South Side Flats neighborhood of Pittsburgh, where it met the Monongahela Connecting Railroad and the Pittsburgh, McKeesport & Youghiogheny (PM&Y).

Mileage on this P&LE branch was reckoned from the passenger terminal back at the Smithfield Street Bridge.

In 1880, William Henry Vanderbilt's Lake Shore and Michigan Southern Railway bought stock to the tune of $200,000 in the P&LE.

Also in 1877, an agreement between the P&LE and the Atlantic & Great Western (Erie) and the Lake Shore and Michigan Southern Railway was reached for routing traffic at Youngstown, Ohio.

This would lead to William Henry Vanderbilt to control of the P&LE as a link in the South Penn and the building of the Pittsburgh, McKeesport and Youghiogheny Railroad.

Then Vanderbilt, aided by Andrew Carnegie, advanced the PM&Y all of the funds to build to Connellsville, Pennsylvania and then lease it to the P&LE for 99 years.

Concurrently in 1883, to get the P&LE ready for the expected new business due to the South Penn linkage, the McKees Rocks shops were built.

Starting in 1934, the Baltimore and Ohio Railroad (B&O) bought trackage rights over P&LE from McKeesport to New Castle.

The P&LE's Pittsburgh passenger train station (interior seen in the lower right photo) sat adjacent the south bank of the Monongahela River at the foot of the Smithfield Street Bridge.

The Pittsburgh Terminal was the railroad's headquarters, passenger train shed, and freight warehouse complex.

The former P&LE headquarters building at the bottom of the Monongahela Incline has been converted into a present-day shopping center, Station Square.

Ticketing agreements with the Erie RR and the P & LE's parent New York Central, passengers boarding in Pittsburgh could ride coaches or sleepers west to Toledo, Detroit, Chicago, and St. Louis, and north to Cleveland, Buffalo, Toronto, Albany and Boston.

The trackage sharing arrangement continued until Amtrak assumed responsibility for the nation's passenger rail service in 1971.

Latest by 1968, only the section between College Hill, Beaver Falls, Aliquippa and P&LE's Pittsburgh Terminal was served by one single roundtrip commuter train per day.

With state support, P&LE continued to operate the commuter run but eventually ended the service on July 12, 1985, after passenger counts had dropped significantly.

However, the PC&Y facilities were just behind the P&LE Locomotive facilities in the main yard, and trackage from the PC&Y crossed the P&LE Mainline at this point, servicing several local businesses in the Bottoms section of McKees Rocks, finally making the previously mentioned interchange.

In 1904, P&LE built the O'Donovan Bridge for easier automobile access from Island Avenue to The Bottoms without crossing the railroad tracks.

This was replaced in 1931 by the McKees Rocks Bridge, which extended to Ohio River Boulevard but still provided access to The Bottoms via Helen Street exit.