While originally part of the Pennsylvania Railroad K funneled trains to the upper level of 30th Street Station. In fact Milepost 0 of the famed PRR Main Line is at the end of the platform at the downtown Suburban Station Since the 70's these trains have all been commuter lines run by SEPTA. SEPTA owned trackage starts at the eastern limits of ZOO interlocking and the old K section of ZOO handles only SEPTA movements. While most movements are straight rail through K movements out of the west end of Powlerton Yard and any special circumstances for trains coming out of SEPTA territory involve special handling. Since SEPTA closed the old PRR BROAD tower and centralized dispatch functions communications with ZOO have become more complicated and for a while after BROAD closed in 2003 misroutes were somewhat common and once I had to be "sent round the Berry" when my Trenton train came out track 4 instead of track 3 w/o ZOO being notified.
Both Amtrak and SEPTA found this arrangement irritating as Amtrak disliked being responsible for tracks that doesn't handle any of its trains and SEPTA for having to hear Amtrak complain about this and refusing to put in any capitol investment (the tracks through there have grown extremely bumpy). SEPTA finally found 5 million dollars to re-signal and re-build this section of ZOO as the new K interlocking, controlled by dispatchers at SEPTA HQ and all through 2008 and early 2009 they went about implementing the project.
The old "K Tower" section, named for one of the 4 towers closed in the 1934 ZOO consolidation, is being transfered to the local commuter rail authority SEPTA. Shown in the upper corners here and here the K section consisted of the 25, 27, 39, 45, 47 and 53 turnouts and 28, 30, 32, 40, 42 and 168 signals. One very surprising development is that the 64 signals and 65 switch (seen here) were included in the re-working. This means that Amtrak will have to get permission from the SEPTA dispatcher for trains entering or leaving the Rundown track to Amtrak's own M of W yard. The Cuttover is scheduled for midnight on Saturday morning so if anyone has time they should go ride SEPTA today to take some final pics of the remaining old hardware.
Anyway, back in2007 I was expecting the worst when it came to the re-signaling of K with its PRR amber position lights and pneumatic point machines. I was hoping they would leave the signals in situ and just re-wire them, but I was in for a pleasant surprise as SEPTA decided to install brand new LED Amber PRR Position Lights. Here are some early pictures I found on Railroad.net:
Since US&S PL-3's aren't made any more the signals were Safetran units and the new point machines were electric. SEPTA also installed new Amber PL's at ARSENAL interlocking so unlike the turncoat LIRR there seems to be someone cool working in the C&S department at SEPTA
Anyway, for your reference I have posted a PDF of the Bulletin order describing the change.
The cutover was a rather slow motion affair with new signals and switches put in place, but wired to the big Model 14 machine in ZOO. This has provided the opportunity for ZOO to have one last hurrah controlling some brand new signals.On a 2009 trip on Amtrak's Pennsylvanian I managed to take a number of the ZOO-attached new signals.
Here's a new Cantilever with the old 30R and 32R signals for 3 and 4 track westbound.
The big signal gantry with the old 40R and 42R signals on track 1 and 2 westbound.
Big gantry with the 181 and 182 exit signals as well as the to-be-removed 32L signal. It's interesting to note that many of the new signals show more aspects than their former counterparts. 181 and 182, for example, both have new lower heads.
The same thing applies to the 183 and 184 exit autos show here in 2012.