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Friday, March 8, 2024

Reading Viaduct Signaling Remains

On November 6th, 1984 the last train departed the historic Reading Terminal in center city Philadelphia 4 days after the completion of the Center City Commuter Connection tunnel that allowed through running between the former Pennsylvania and Reading electrified commuter rail systems. Immediately after crews began to rip up the tracks as the tunnel had rendered both Reading Terminal and about 2 miles of elevated main line redundant. This also marked the end of RACE STREET as an active interlocking station and its task of signaling trains in and out of the 13 track station complex from the 4-track Reading Viaduct. Built in 1930 in conjunction of the Reading's own suburban electrification project to replace the previous interlocking from the 1890's, RACE STREET, or "RA" as it was known in the days of the telegraph, would fall to the wreckers ball as the viaduct between Arch and Vine streets was turned into a mix of event space and parking to support the new Pennsylvania Convention Center, that would also employ the Terminal train shed as an event space.

The surprisingly modern RACE STREET ("RA") tower at left.

While the demise of a historic terminal interlocking tower is nothing new, even finding a photos of RACE STREET was devilishly hard due to its position two blocks from the end of the passenger platforms and often located behind stored MU equipment. At 111 levers, RACE STREET's US&S Model 14 machine was as large as the one in HARRIS, but it features only 68 working levers, the same amount as the total number of levers in CORK. In addition to fanning 4 main line tracks into 13 station tracks, it also featured a junction with the single (originally three) track "City Branch" freight line and two storage pockets on the tower side of the terminal throat. The interlocking consisted of roughly 4 parts, each delineated complimentary signals. From north to south this was the outer set of medium speed crossovers, then the City Branch junction with a 3x4 double-slip field, the trailing point double slip ladder and then the final terminal fan. The terminal area made liberal use of Restricted speed routes with no signaled routes in the fan and only a select few in the trailing ladder. Of course this is all mostly academic as everything south of the City Branch junction was demolished  What about north of the junction?

Despite the demolition of both the tower and the core of its interlocking plant, significant artifacts of race street remain in roughly the condition they were left in 1984. This is because the main line viaduct north of Vine Street was abandoned in place as an electric power right of way to reach a rail power substation. While much of the track structure was removed, the overhead lines and their supporting gantries were needed to feed the electric power and attached to those gantries were RACE STREET's 1930 vintage color light signals. In 2012 the substation was replaced, ending active use of the viaduct for rail purposes, and the viaduct became an urban exploration hot spot with plans to eventually convert it into a High Line style linear park.

Working northward, the first surviving signal bridge is on the curve immediately adjacent to the Callowhill 25hz railroad power substation and features northbound high signals 20L and 18L for tracks 4 and 2, in addition to southbound high signals 28R and 26R for tracks 1 and 3.

The southbound 28R and 26R signals featured a full upper head, a middle head with green and red lamps and a Reading style horizontal head with the yellow Restricting lamp. The reason for the middle Green lamp without an accompanying yellow is somewhat unclear but I suspect that R/Y/R Medium Approach was unavailable in favor of R/R/Y Restricting. The only non-restricting signal south of here is on track #2  so both Approach Medium and Medium Clear would be possible.

For northbound trains the 18L and 20L signals are protecting medium speed main line crossovers. Track 4 had no diverging routed and was only supplied with a R/*/Y below the 20L full speed head while the 18L had two regular medium speed routes over the #17 and #15 switches. 

Both the 18L and 20: also feature metal ID tags on the back of the upper signal head. I'll also point out that all of the color light signal hardware is US&S style TR target (tri-light) with unitized lamp housings.

The next surviving gantry hosts the southbound 16R and 14R track 2 and 4 home signals and the southbound automatic track 3 and 1 exit signals. 

The 16R and 14R are mirrors of 20L and 18L except in this case the local track gets the diverging route over the #13 switch. 

The automatic exit signals are also nothing special, although the numbering system is a bit hard to figure out and apply to further automatic that are not on the diagram. It is also important to point out that tracks 1, 2 and 4 were bi-directional with the 16L signal able to display Slow Clear for straight movements, while the 14L on track #3 could only display Restricting.

A mere 800 feet down the line was the first automatic signal location with three northbound signals on tracks 1, 2 and 4, and southbound signals on all 4 tracks. The reason for the asymmetrical signaling was due to the presence of the Reading's MU storage yards on the east side of the line at North Broad. Deadhead moves heading to and from the yard would use track #4 in the shoulder peak.

One additional feature was the presence of lower heads on the tracks 3 and 4 signals in the normal direction. it appears that one lamp is green, the other yellow to allow for the display of Y/G Approach Medium and Y/Y/ Advance Approach given the short signal distances.

Another 1300 feet to the north there is one last automatic signal location similar to the first, however I was disinclined to reach it due to the amount of vegetation that would have hindered attempts at photography. With recent brush clearance projects I might head back and if I am successful will update the page. It is anticipated that when the Reading Viaduct park is completed the overhead signals will be preserved as part of the attraction. 

 In fact Phase 1 of the park on the old City Branch already features the preserved 12R (later downgraded to a fixed approach signal) given a fresh coat of paint and left in the same location. I will mention that as long as the Viaduct is still an urbex location one can get a bit closer to the signals by taking advantage of the still intact access ladders. A feature that was removed from the 12R.

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