First a little background. The Enola Branch, which runs from Enola yard to the former Atglen and Susquehanna split at the former PORT interlocking south of COLA was part of the former PRR "Low Grade" system of routes that diverted main line freight trains off the Main Line through Lancaster and Harrisburg. Built in the first decade of the 20th century as traffic volumes were riding the Enola Branch was later electrified in the late 1930's and then re-electrified in the early 1980's before being relegated to backwater status as Conrail re-routed its freight off of the former PRR routes that were largely under the control of Amtrak.
Part of this route was already used by the Northern Central line from Baltimore to Harrisburg and not wanting to disrupt existing operations the PRR simply doubled it up, building the new 2-track Enola Branch right along side the old 2-track Northern Central main creating a rare (for North America at least) "2 + 2" line instead of the more typical 4-track configuration. Both mains were run under Rule 251 ABS with the only break from the parallelism coming at LEMO where the NCRR elevated to junction with the Cumberland Valley leaving the "low grade" line to stick by the river.
Here is a 1938 interlocking diagram of LEMO interlocking showing the NCRR and its junction with the CVRR while the Enola Branch shuns both down by the river. LEMO was the only main line diamond crossing of electrified tracks on the PRR.
LEMO, originally known as J tower, was actually preserved and now lives at the Strassburg Railroad. The junction, on the other hand, with its multiple wyes and bridges, now lays completely abandoned as Conrail shifted traffic to the former Reading route.
Moving our attention back to the Enola Branch we see a pair of automatic position light signals on either side of the CVRR bridge and as luck would have it these still exist as of 2013. The first of these is eastbound automatic 832E mounted on a centenary post just north of the Cumberland Valley bridge. The auto number is actually derived from Northern Central mileage from Baltimore, even thought the Enola Branch mileage counts from Parkesburg. In neither case has the number reflected the reality of rail operations for nearly 30 years.
Closeup of the signal. There really isn't a lot to see here except note the lack of approach lighting. This was because when the PRR electrified a reliable source of signal power was available via the 6000 V 100Hz AC supply on the catenary poles. Without the need to conserve batteries the PRR turned on the signals full time.
The westbound signal is offset a bit from the eastbound and consists of automatic 831W. This signal supports a lower | head for Approach Medium indications. For those who only know STELL as it existed in its later years with Rule 251 operation running all the way to DAY, this indication might seem a little odd, but up through the mid-80's when DAY tower was still active, both tracks from the Enola/NCRR junction at what would become STELL to DAY were bi-directional, giving westbound trains a choice. When NS adjusted the signaling on the line in the 2010 time frame the ABS block between STELL and DAY was removed, resulting in Approach being the best indication that 831W can display.
Also visible in this station are one of 4 High Tension Field Switches what were part of the PRR 25Hz Traction Power System. The PRR used a single phase electrification system with power being transmitted long distances using 138 kV transmission lines consisting of two 69 kV lines operating 180 degrees out of phase. HT switchgear such as this is used to isolate sections of the 138 kV transmission line and are normally found at the 138 kV to 12 kV substation located every 10 miles or so. Switchgear such as this cannot function as a circuit breaker and therefore cannot switch lines under load. These switches were only thrown when the substations they were feeding had all been disconnected from the 12 kV overhead lines.
The upper Enola Branch supported one 138 kV circuit with another two running up the other side of the river along the Main Line. At Harrisburg both of these circuits crossed the Susquehanna River via the Cumberland Valley Bridge to serve the Enola substation. At LEMO the single Enola circuit split to tap both of the Main Line circuits. The field switch was used to choose which of the two Main Line circuits the Enola would feed from.In this wider view you can sww the two 138 kV circuits from the field switch joining into one on the pole the signal is attached to.
Another point of note is the lack of the 6000 kV signal power line I mentioned earlier. It could be that Conrail swapped this signal location over to commercial supplies or that they simply utilized the feed from Amtrak seen here in this view across the disused Cumberland Valley Bridge. The 138 kV circuits were removed in the 2010/11 scrapping project. Amtrak made use of only one 138 kV circuit running from the Safe harbor hydro dam via the Royalton Branch with the Enola circuit remaining idle.
The next signaling location located at about NCRR Milepost 81 shows the 4-track signal bridge that used to be common on this part of the line. These were in place from the dawn of position light signaling, probably in the 1920's, all the way until the 2010/2011 scrapping project. Note I didn't say re-signaling project as while the signals themselves were replaced the logic that drove them was not.
Here we see the 809/810 signal bridge looking south with the empty NCRR RoW to the right. The relay boxes are elevated due to the flooding risk from the Susquehanna River.
Here is a closeup of the 810E signal for eastbound movements on the Enola Branch. Typical ABS signal, but the 2+2 layout put the northbound NCRR signal directly behind it on the signal bridge. In fact that signal was simply left in place when the NCRR tracks were ripped out!
The NCRR ghost signal is plainly visible in this northward view along side the still active 809W signal. If this signal bridge looks a bit odd its because it was elevated on risers by about 5 feet to clear the wires in the 1938 electrification project. Also note the 65 milepost which as I mentions before counts from Parkesburg and clashes with the NCRR numbered signals.
Close view of the 809W position light. Note the two wires for the 6000 V 100Hz signal power supply. Default indication for both this and 810E is Clear.
The next signal is the 78 automatic and it follows the same pattern as the 81 auto just without the ghost signals. The entire Port Road / Enola Branch sees quite a few extra long 3 mile signal blocks.
788E signal close up displaying Clear. The mounting cage for the NCRR signal is still visible.
Opposite, non-backlit view of the 78 auto bridge. The riser stilts are a bit more visible in this view.
Close view of the 789W automatic signal The box structure was to protect maintainers working on the lower head from the electrification wires. In this case the lower head consisted of a Stop and Proceed marker light, since replaced by the large reflective Conrail style number plate.
The 76 automatic signaling location was situated just south of the Pennsylvania Turnpike bridge and could be see from the eastbound driving lanes when looking south. This location was given a bit of a safety upgrade by Conrail when they replaced the catwalk railings with new double bar types.
768E automatic signal displaying Clear.
View from the south showing the removed NCRR signal positions.
767W automatic displaying Clear.
The 74 auto sports a full set of ghost signals. The old catenary pole that supports the 100hz signal power transformers seems to have having a slight structural integrity issue.
The active 744E automatic signal displaying Clear. The E/W suffix was applied by Conrail to replace the original PRR N prefix which had been affixed to both sets of signals. The prefix system using L and C is still in evidence lower down on the Port Road.
Opposite view with a clear shot of the cabinet style relay box. All four tracks were originally cab signaled which were powered by electro-mechanical pulse code generators in the relay cabinet.
743W automatic displaying Clear.
The 72 automatic is (was?) located in downtown Goldsboro, PA. The only reason I say "was" is that it is somewhat hard to confirm if a new signal was installed at that location. The relay boxes are still in place so it could be that the masts are just hiding somehow, but I failed to locate them on either Google's overhead or while riding the recent Amtrak excursion train. It could be that NS doubled up on some of the blocks to save $ or is doing something fancy with the cab signaling.
Backlit 722E automatic.
Northward view of the signal bridge looking towards downtown Goldsboro.
Close-up shot of the 721W automatic. The 6000 V signal power bracket looks like its having some trouble.
The mile 70 automatic is actually special because it is located at the former location of CLY Tower , which served the same purpose that the Conrail era WAGO interlocking does today. The 702E automatic signal is actually mounted on CLY's former eastbound home signal bridge.
The 702E automatic displays Approach for the Stop signal at WAGO interlocking. This signal is equipped with a lower head for medium speed routes at WAGO which was carried over onto the new Darth mast as well so something at WAGO needs to provide for a medium speed route even if everything seems to lead into Restricted speed territory.
701W signal for westbound moves. CLY did not have a northward signal bridge, instead using masts and dwarfs. Off to the left of this photo is the location of the #58 Goldsboro substation, which bridged the gap between the Enola and Rowena substations.
You can see the original layout of the interlocking here. CLY was one of the very few pure mechanical interlockings in the electrified zone and supported only slow speed crossover movements. It is no wonder that NCRR and Enola trains mostly kept to themselves. One interesting feature of CLY was that the switch pipelines had to run in a trench behind the passenger platform.
CLY tower came equipped with a 44-lever mechanical machine. It was built from the same type of stone used in the Rockville and Shocks Mill bridges. A testament to the wealth and resources available to the great Pennsylvania Railroad.
So I keep saying that almost all of these signals have been replaced, but now I can finally provide an example. So here we see the 'new' 531E signal that replaced the old 702E. NS has finally gotten around to standardizing on the A&S mileage, but the Approach Medium indication is still confusing. Perhaps it is in anticipation of a future CTC project.