On the south end of the Harrisburg Passenger Station, tucked away in a two-story addition dating back to the final phase of electrification in 1937 two significant PRR facilities operated around the clock. State Interlocking Tower is on the far south end of the station building and originally controlled the east end operations of the passenger terminal, access to the Cumberland Valley line to Hagerstown and the Northern Central via Lemoyne Junction on the West side of the Cumberland Valley Bridge. In addition to these important mainline connections State also controlled the Columbia branch that comes up from Royalton as well as access to both PRR and Railway Express Agency warehouses that handled local express traffic off the passenger trains.
Opening in 1937 as part of the terminal electrification, State Tower contained a standard Model 14, Union Switch and Signal unit, customary in most PRR interlocking towers. The interlocking was operated in conjunction with Harris to coordinate the combining and splitting of passenger trains in the station while also facilitating engine changes and yard moves needed to maintain passenger operations. While State still operates as a local block and interlocking tower, the physical plant is not nearly as intricate as it once was. Since traffic no longer operates on and off the Cumberland Valley Bridge and Norfolk Southern makes no connection from the Columbia Branch at the passenger station, most operations focus on Amtrak trains arriving and departing for Philadelphia. Occasionally a bad order coach or cab car will be switched out here or turned on the wye but typically operation is pretty straightforward. Several responsibilities were added to State’s territory after Roy and Harris were decommissioned, giving State the remaining control of the NS connector at Capitol Interlocking (just west of Harris) and Roy interlocking where the NS Columbia branch diverges off the mainline further east in Royalton.
Also part of the 1937 construction, the Harrisburg Power Dispatcher’s Office was constructed to monitor and control electrical supply and loads on all electrified territory from Harrisburg and Enola east to Thorndale on the main and low-grade routes and south to Perryville. This facility survives as an incredible symbol of the strides the PRR made in electric traction technology and remains intact although not in use. The facility is still occupied by Amtrak’s power dispatcher who now works from a computer terminal in the center control atrium of the original installation. When visiting the facility last fall there was discussion of this location closing with completion of Amtrak’s new CNOC pending, but to my knowledge the facility is maintained to date. The Harrisburg facility was one of three such installations on the PRR with the other two at 30th Street Station in Philadelphia and the Service Plant building of Penn Station in New York City, neither of which are still intact.