Moving to the Western Limits of Pittsburgh from Wilmerding, we come to a key location on the PRR Eastern Division Mainline. Three miles from the Pittsburgh Division boundary and Penn Station proper, the Ohio River Connecting Bridge served as the western end to a freight bypass early on routing trains around the congested Pennsy terminal in Pittsburgh by means of the Port Perry Branch from Pitcairn Yard, the Monongahela Line and the Ohio Connecting Bridge to rejoin the Fort Wayne Mainline.
On the South bank of the Ohio River, a "branch" came West from the junction of the Monongahela Line and Panhandle Main across from the City Center, through a complicated junction, the Scully Branch made connection with OC Bridge at Esplen Interlocking. From here the East leg of a Wye directs traffic to the Fort Wayne line accross the OC, and the West Leg moves traffic from the the Fort Wayne to the Panhandle via the Scully Branch connection in Carnegie PA. On the North side of the bridge, a fly-over junction with the Fort Wayne Line ties the East leg of the Wye into Island Ave Yard, the Mainline East, and the Conemaugh Line via Federal St. On the West leg the Panhandle makes a long descent to Jacks Run interlocking (later renamed CP Bell in Conrail's CTC project) allowing bi-directional access for diverting traffic around the City Center.
The bridge itself deserves some attention, originally being built in 1890 as the single track Ohio Connecting Railroad Bridge, after completion and several years of service, the key structure proved worthy of expansion. Started in 1913 and completed in 1915 construction took place in full Pennsy fashion. Engineers expanded the structure from single to double track, literally at times around the existing structure to avoid shutting the connection down causing major delays to rail traffic. Once completed the new bridge complimented several other projects, mainly the Brilliant Branch to add another bypass for traffic to and from the Panhandle around the station area, onto the Conemaugh Line, then back to the Main in East Liberty via the new 1.8 mile four tracked Brilliant Branch.
Unlike the Panhandle Mainline and the Brilliant Branch, the OC Bridge still serves the busy Mon Line bypass for Norfolk Southern, moving long intermodal and heavy mineral traffic around the City Center, a testament to the construction and forward thinking of engineering staff who built the Standard Railroad of the World.