19-06-30 PHOTOS: CALN

On the former Pennsylvania Railroad Main Line between Philadelphia and Harrisburg, Thorndale was the western end of the Philadelphia and Trenton low-grade freight route and a helper base where steam and electric helpers were attached to help westbound freights get up and over the hill at Gap, PA.  As part of the 1937 electrification project, a new interlocking plant and tower, THORN, was constructed at Thorndale which also controlled a number of remote interlockings with the western most located about 2 miles away at a location called CALN.  This served as the western end of the Thorndale yard, but as freight traffic moved off the old PRR Main Line the interlocking was simplified until it was serving mostly MoW moves and, after 1999, the occasional jump around of a SEPTA train stopped at the new Thorndale Station. 

Around 2019 there were rumblings that the slow Harrisburg Line rebuilding effort was finally going to move east from Parkesburg so I headed out to get some photos of the classic layout as well as some new photos of THORN which can all be found here. 

While the current state of CALN is pretty bare with the interlocking only in service on tracks 1, 2 and 5, the 1937 vintage overhead wires show the true history of the layout.

The westbound signal bridge also has a number of ghost signals with the old track 4 signal being converted to an automatic. 

I had arrived in time to catch an eastbound Keystone train with Metroliner Cab Car #9644 in the lead and  ACS-86 #670 pushing.

CALN's current claim to fame is a vintage Penn Central interlocking signal. 

THORN tower is located directly behind a small strip mall on US 30 and is still in service as a manned interlocking tower as of 2019.

Despite all manner of abandonments and simplifications, THORN still supports a 6 track full crossover and has a beefy pneumatic plant to power all of the vintage point machines. 

THORN is an example of the last style of PRR tower, all brick with no bay windows.

Today the Thorndale SEPTA station is the terminus of the busy R5 line out of Philadelphia.  Standard practice is for westbound trains to cross over all 6 tracks to stop at the single high level platform on track #1.   Here we see an R5 Thorndale train of Silverliner IVs led by SEPTA #124.

As Keystone trains run on a fairly infrequent headway, most mid-day and weekend Thorndale trains lay over for about 20 minutes before heading back to Center City.  Here we can see Silverliner IV #397 doing the honor. 

When a SEPTA local isn't blocking track #1, Keystone trains are free to speed through at 90mph.  Here we somehow see Amtrak ACS-86 #670 again leading an eastbound Keystone trainset with Metroliner cab car #9645 on the rear end. 

The east end of THORN interlocking features a stub track and ghost signal for the old P&T low grade line that routed freight traffic around the congested Philadelphia terminal area.  The line was reduced to a single track in the 1970's and then completely abandoned in the mid-80's as through freights were moved to the former Reading territory. Today the right of way between Thorndale and Glendale is used as an impromptu hiking train.

The use of stubs and ghost signals is a less expensive alternative to continually altering the interlocking's 1937 vintage relay logic. 

 I am not sure if this AC MOTOR STOP sign on the track #5 stub is original or part of the modification process as the Thorndale yard did have some non-electrified tracks supporting the steam and diesel helpers.

A quick stop at DOWNS interlocking in Downintown, PA revealed this old derrick crane that used to serve a small industrial yard and team track. 

Today a rare left hand dwarf still governs the last remaining yard track entering DOWNS interlocking via a hand operated switch.

Leaving Downingtown one passes under abandoned P&T viaduct over Brandywine Creek.  It is inevitable that the P&T right of will will be converted into a proper rail train, but the number of bridges over busy roads will require significant funding to make safe.

Thanks for reading, next week we head back to Pittsburgh for one last go at documenting Conrail and PRR signaling.