Pittsburgh Southern

by Joseph Brennan

slice of map

A slice of the large map I created.

The Port Authority of Allegheny County operates a light rail system called The T, running in subway downtown and then along two routes into the southern suburbs. In 2015 I had a chance to ride from Mt Lebanon to Allegheny on the Red Line, and in 2016 from South Hills Village to the city on the Blue Line, and I was hooked. I could see a lot of modern construction, and many traces of leftovers from long ago. I wanted to figure out what was what.

Yes, a total of three days in Pittsburgh, and five nights in Mt Lebanon. It amazes me too that I became so interested. If dozens of other people had written on this subject I wouldn't feel any need. But not so many did, so I will.

I am presenting my notes and observations mostly in graphical form, a map depicting passenger services of today and yesterday. In addition to the existing T the map shows where the Washington and Charleroi interurbans continued south, the routes of south side trolleys that lasted into the post-war period, the busways, and mainline "steam" railroads that once had passenger services.

Pittsburgh Southern itself was the name of the most obscure railway I have ever come across. It ran for five years around 1880 and unlike most abandoned railways it has been obliterated from the landscape. It's on my map but its location is a best guess from the scant materials available. I am using the name because these pages are about the territory directly south of Pittsburgh.

The two lines of The T are a remnant of a once large trolley system operated by a company called Pittsburgh Railways. They survived for reasons both political and practical. The Blue Line was part of a modest interurban railway system that ran into Washington County. The term interurban refers to an electric railway that ran between towns, a hybrid form between city trolleys and steam railroads. The Red Line by contrast was built as a local trolley line, but while it does have some street running in the Beechmont neighborhood, it was an unusual trolley line with several high bridges and a good amount of private right of way in order to serve a very hilly territory.

The two T lines separate at South Hills Junction but come together again in Castle Shannon. The Blue Line runs entirely on private right of way through a less populated area and has fewer stops, so it is the faster route, and cars to the outer branches almost all run via the Blue. The Red Line cars almost all end at Overbrook Junction. The two routes were rebuilt in stages starting in 1980. Stage One, completed from 1984 to 1987, resulted in the introduction of Light Rail Vehicles (LRVs), the downtown subway, a rebuilt Red Line including the Mt Lebanon tunnel, the branch to South Hills Village, and a yard and maintenance shops at South Hills Village. Stage Two, the totally rebuilt Blue Line and upgraded branch to Library, was completed in 2004.

The names Red Line and Blue line were not adopted until 2010. The Pittsburgh Railways route numbering scheme ran clockwise from the North Side. The Blue Line was 35 to Library, 36 to Drake, and 37 short turns at Overbrook Junction. The interurban cars to Washington County were not numbered. Routes 38 and 39 were street running in West Liberty Avenue— 38 to the Clearview Loop in Mount Lebanon, and 39 into Brookline— and 40 was street running up to Mount Washington. The present Red Line was 42 to Dormont Junction and 43 short turns at Neeld. After 38 was abandoned, 42/38 was created as the Red Line 42 plus running in the former 38 to Clearview Loop. The segment from Clearview Loop to Overbrook Junction was single track with limited service. For many years it had either a one-car shuttle called 38A during limited hours, or had a few runs off 38 and 42/38 running in the main direction in rush hours. It was only in 1987 that full-time service began as part of routes 42C and 42S.

In the 1980s PAT began renumbering bus routes to rationalize them after years of adding and dropping routes, and the light rail lines were included. There was a little-known scheme: a route ending 1 or 6 was a local to downtown, 2 or 7 was a limited-stop route to downtown, 3 or 8 was an express that skipped inner stops, and the rest were various locals. In accordance with the scheme the light rail lines were changed in 1984. The present Red Line became 42 (one of a few that regained their old numbers), and the present Blue Line became 47. But the system also included letter suffixes to designate terminals. Routes commonly operated were: 42 Mount Lebanon only, 42C Castle Shannon, 42S South Hills Village, 42L Library (1993 to 2004); and 47 Shannon (Castle Shannon loop), 47L Library, 47S South Hills, 47D Drake (route no longer operated). 44 was used for short runs that did not go downtown, like 44L for off hour runs from Washington Junction to Library and 44D from Castle Shannon to Drake. The former route 52 seems like an exception to the rule, but maybe it was justified by the few cars that continued south on the 47S route (which were not called 52S). This will not be on the test. You don't need to know any of this unless you are reading outdated descriptions of the services.

Besides the Red and Blue, there was a Brown Line, called 52 before 2010. Known as the Allentown line, it avoided the tunnel by going up over Mount Washington in streets. It combined parts of the older 47 and 48 routes that went through the tunnel and came up from South Hills Junction with the 49 that came up the city side, all of which were eliminated in 1971. The 52 provided an increasingly limited service to South Hills Junction until 2011. Tracks for it to terminate there without blocking Red and Blue services are still in place, and those tracks are used also when "Subway Local" cars run in connection with stadium events. The Allentown Line tracks and overhead are still maintained to provide an alternate route for the Red and Blue lines when the tunnel is closed for maintenance or other reasons.


Notes on the PAT Light Rail Lines.

Notes on the Pittsburgh and Castle Shannon Railroad and how it became the Blue Line route.

Notes on the Overbrook Line film showing its state in 1989 before the rebuilding.

Notes on the Pittsburgh Southern Railroad — a Lost Road.

Notes on the Castle Shannon Inclines and the Coal Tunnel too.

A large map of The T system with historical and other notes.

Notes on the Interurbans to Charleroi and Washington.

A large map of the interurban line to Washington beyond the T map.

A large map of the interurban line to Charleroi beyond the T map.


For further reading I am happy to pass along links to some interesting sources.

  • Wikipedia: Pittsburgh Light Rail
  • Wikipedia: Pittsburgh Red Line
  • Wikipedia: Pittsburgh Blue Line
  • Wikipedia: Pittsburgh Brown Line
  • Wikipedia: Pittsburgh Railways (1902-1964)
  • Wikipedia: Pittsburgh and Castle Shannon Railroad
  • Historic American Engineering Record: Pittsburgh and Castle Shannon Railroad
  • Carrick Overbrook History: Pittsburgh and Castle Shannon Railroad
  • Bridgehunter: Pittsburgh and Castle Shannon Railroad
  • McNally's Railroad Collectables: Pittsburgh and Castle Shannon Railroad
  • The Brookline Connection: Trolleys in Brookline
  • PGH Bridges: Mount Washington Transit Tunnel
  • TransitGuru: Pittsburgh > Transit History [maps]
  • —— Street and Interurban Trackage 1859-1959
  • University of Pittsburgh: Historic Pittsburgh Maps Collection
  • Rails and Trails: Western Pennsylvania Rights of Way (open in Google Earth)
  • Pennsylvania Dept of Transportation: County Type 10 Maps (Historic)
  • Penn Pilot: Historical Aerial Photographs of Pennsylvania
  • Railway Station Lists: Pennsylvania Interurban Railways 01
  • Charleroi Interurban
  • Jon Bell: Pittsburgh, Pennsylvania
  • Pittsburgh Railways Online
  • Port Authority of Allegheny County: Inclines
  • Wikipedia: Monongahela Incline
  • Wikipedia: Duquesne Incline
  • The Society for the Preservation of the Duquesne Heights Incline
  • Old Pittsburgh Maps: Pittsburgh's Incline History
  • Western Pennsylvania History, Summer 2014— Ed Reis: Skybus...