PHOTOS: Inside GLENWOOD JCT

GLENNWOOD JCT, aka WJ, is located in Pittsburgh's Glenwood neighborhood on the banks of the Monongahela River. Built in 1908 by the Baltimore and Ohio railroad, the tower remained in service for almost a century at the eastern end of Glenwood yard before closing in 2003. Like many towers, GLENWOOD JCT was first protected by the massive changes in the industrial economy in the 1980's and 90's before being ultimately ultimately done in by them. Shortly before its closure, one of my foreign correspondents asked for my assistance in visiting the tower while on a North American trip and they sent me the resulting photos after successfully charming their way inside. Twenty years later I was able to visit GLENWOOD JCT myself and combined with the interior photos I hope to cover the tower and its history before its increasingly likely demise.

GLENWOOD JCT In Service in 2003

 

GLENWOOD JCT out of service in 2021

GLENNWOOD JCT is frequently photographed due to its proximity to Pittsburgh's Glenwood Bridge that provides an overhead view of Glenwood Yard. The tower is located on what was known as the CSX P&W Subdivision, a line running to the north and west of Pittsburgh that was incorporated into the B&O in 1884, forming part of their westward main line to Chicago via Youngstown and Akron. The P&W is a slow, curvy route with access to downtown Pittsburgh via a several mile long stub end track that terminated at the Grant Street Station. In 1934 the B&O negotiated trackage rights on the Pittsburgh and Lake Erie between Braddock and New Castle, PA with the vast majority of B&O traffic eventually shifting to that route. This shift is what likely kept GLENWOOD JCT active into the 21st century as both the P&W route and passenger services into Pittsburgh became subject to disinvestment. This combined with CSX's general use of manned interlocking towers on its Main Line between Washington and Pittsburgh up into the early 2000's (with 2, WB in Brunswick and VI in Connelsville, lasting into the 2010's) to keep the tower open since there was a sufficient pool of operators.

GLENWOOD JCT closure came at the hands of the 1999 Conrail merger that shook up CSX's operations between the Northeast and Chicago. Renewed investment in the corridor closed many of aforementioned B&O main line towers and 20 years of Pittsburgh area deindustrialization rendered both the P&W Sub and the once prominent Glenwood Yard that it served, largely obsolete. A wholesale P&W abandonment north of the city was averted by a lease to the Allegheny Valley Railroad. The one hiccup was the use of the P&W between Braddock and downtown Pittsburgh by Amtrak's Capitol Limited which pretty much required signaling on this part of the route. The solution was a complete removal of the interlocking plant and reduction of the line to a single CTC track, which showed exactly how little value GLENWOOD JCT had been providing to rail operations in the area. The AVR lease likely played a role in the tower's survival beyond its closure. AVR didn't own it so they couldn't demolish it, but it wasn't CSX's problem so no need to spend money to remove an asbestos trap. In 2019 AVR purchased the P&W sub outright so we will see if they find a use for the structure at Glenwood yard, demolish it or allow it to burn down "on its own".

GLENWOOD JCT is a 2.5 story wooden interlocking tower built in the B&O style with a variety of updates over its life. The tower consists of an upper operator's floor, a lower floor relay room and a concrete basement level that is only dug about halfway into the ground. This extra half story gives GLENWOOD JCT a noticeable bit of extra height. As the lower floors show no evidence of any mechanical lever frame or pipelines, it is likely that the tower was built was a state of the art power interlocking machine, most likely one from Union Switch and Signal as GLENWOOD JCT was located only a couple miles from US&S's manufacturing plane in Swissvale, PA.

At some point the original interlocking machine was replaced by a familiar US&S Model 14. The tower is also the quintessential example of Tower Window Syndrome as it was built with a fully windowed upper level that by 1983 had seen most of those covered over by solid walls and siding. By the 1990s the remaining full height drop-sash windows were replaced by half height replacement windows. This coincided with the tower being clad in CSX standard beige vinyl siding and the slate roof being replaced by asphalt shingles.

   

Original windows

Many full height windows boarded up

Cheap replacement windows fitted.

Despite all of the modifications, the neglect of the past 20 years is allowing some of the original wooden features to shine through.

GLENWOOD JCT was built on a double track main line that was converted to bi-directional operation around 1980's, likely in conjunction with the expanded PATrain commuter rail service. (See my article on LAUGHLIN JCT for more information about the notable interlocking two miles to the west.) On the main line (P&W Sub) GLENWOOD JCT had both an east and west end, each covering a crossover and a yard access track. The west end was surrounded by a pair of B&O CPL bracket masts while the east end had a single signal bridge with the westbound home signals and eastbound exit signals that supported the bi-directional operation to the P&LE junction BRADDOCK. The inner and outer controlled signals at GLENWOOD JCT created the short signal block in turn motivated the 6 orbital complete B&O CPL at LAUGHLIN JCT as trains approaching GLENWOOD JCT from the west could get a Slow Approach at the 36L or 40L signals for a stop at the 44L or 42L signals which necessitated the use of Approach Slow and Medium Approach Slow (the 11 and 7 o'clock orbitals) at LAUGHLIN JCT.

 

Beware the Three Headed Monster

 In North American railroad Signaling truly "universal" rules are pretty rare as in almost every situation one can usually find exceptions.  For having a high green reserved exclusively for Clear is pretty universal except the Bessemer and Lake Erie uses G/*Y* for Approach Limited and G/Y for Limited Clear.  Well another one of these rules is that intermediate signals either have one or two heads. By intermediate signals I am referring to signals with a number plate or signals with offset heads that cannot display an absolute Stop indication. Well there is one big exception to this and it is the Y/R/G Approach Slow indication used by a number of Conrail predecessors like the New York Central and Reading Systems and, more recently, CSX via the Seaboard System. 

 

This results in what I like to call a "three headed monster" in that you have an exceptionally tall intermediate signal that makes one question if they are at an interlocking or not.  Although potentially less of an issue due to PTC, salience is a huge human factors issue and when designing a signaling system from scratch like Caltrain did, making every absolute signal three heads, every automatic distant signals two heads and every basic block signal one head makes it harder for the engineer to become confused about what sort of signal is coming up. The Y/R/G three headed monster sort of blows this approach out of the water, but fortunately Approach Slow is one of the less commonly encountered indications. 

However if one is able to look past the signal policy issues and get into the fun world of rare signaling setups, CSX's three headed monster as a few additional tricks up its sleeve. If an interlocking has both slow and Medium/Limited Speed then you get a 7 lamp, 3 head intermediate signal (GYR-GR-GR) like the ones at Milepost 70 west of Point of Rocks.

 Alright, but I think we can do even better!  What if we had a situation with both Slow and Medium Speed routes AND short signal blocks between that next interlocking and one after.  Well, then we'd have an 8 lamp, 3 head intermediate signal (GYR-GYR-GR) and thanks to some recent capacity expansion and re-signaling work an example now exists in the Richmond area on the Belt Line just west of AY wye.

Don't forget, if CSX had simply adopted the NORAC style signal rules with Y/Y Approach Slow and *Y* Advance Approach they would have been able to do this with 6 lamps and 2 heads, but thanks to their Dixieland myopia we now have what is probably the ultimate intermediate signal. The fact that the masts are on both tracks is even better, 

 
Before I go I would like to mention that there is another three headed intermediate signal still in use and that would be Y/Y/G Approach Diverging on Kansas City Southern. Some newer materials are showing the use of Y/Y and with all the recent re-signaling I am unsure if any Y/Y/G still survives, but it technically could exist. Also, in case anyone was wondering if Canada and its crazy quilt of signal indications has a three headed intermediate, they do not as the indication chart would show it with offset heads and all offset head indications have at most two heads. 

Anyway, if I missed anything or you know other examples of an ultimate intermediate signal location please let me know in the comments.

PTC In Practice - A Passengers Perspective

 It was once again time for my annual round trip to Georgia via Amtrak Trains 79, 19 and 20 and I was actually able to experience some PTC related issues, one on CSX and one on NS, which can perhaps shed a bit of light on how PTC has been impacting passenger trains on the national network.  

SOUTH MILFORD, exact site of the positive stop event.

The first incident took place at SOUTH MILFORD interlocking on the CSX RF&P sub, which is equipped with both cab signals and ETMS PTC (for now). As my southbound Train 79 rounded the curve on Clear signals, the southbound track 3 signal dropped to Stop which tripped the PTC system and put the train into emergency. The train actually got stopped before passing the Stop signal, but the emergency brake application resulted in the crew having to stop and inspect the train. Total delay was about five minutes, but the interesting PTC takeaways were that it was able to trigger an emergency brake application instead of a full service penalty type application typically used with these types of safety system. Penalty applications don't require an inspection and, in the case of freight trains, are unlikely to cause a derailment.  Not sure if this is a passenger or Amtrak specific configuration. 

The other point of note was that the PTC was able to get a notification as to the change of block state after the train already had effective movement authority through the interlocking. This isn't surprising, but it is worth noting.  Not sure how long it took to get the update or if the concurrent cab signal system was involved. Under ACSES and potentially NS's implementation, approaching an absolute signal under restricting cab signals is what triggers the positive stop functionality. Without cabs the update would require wireless data reception. 

Approach Diverging on the Southern Main Line

The second event happened on the Norfolk Southern, Southern Main Line at the Milepost 564.8 automatic signal as it displayed an Approach Diverging (Y/G) signal indication for a diverging movement at BALDWIN interlocking.  For whatever reason the PTC system detected the block as occupied and enforced Restricting speed throughout its entire length. Because this took place at night, this meant a 10mph crawl for nearly 3 miles. The restriction lifted upon taking the Diverging Clear signal at BALDWIN. Engineer notified both the PTC trouble desk and the dispatcher. Total delay for this one issue was a whopping 19 minutes. My takeaway was perhaps a rules modification that allows for a train passing a proceed wayside indication to be relieved of the 1/2 vision stop requirement of Restricted speed being imposed by an erroneous PTC indication upon the permission of the dispatcher and/or PTC trouble desk.

Harrisburg Power Dispatcher's Office to be Preserved!

 Amtrak's Harrisburg terminal complex has not one but three signaling related landmarks of great historic value.  The first is HARRIS tower, closed in 1992 and completely restored by the Harrisburg Chapter NRHS to simulated working condition, it represents the absolute pinnacle of signaling preservation.  Th second is STATE tower, closed by Amtrak in 2016, it remains preserved, but not restored or open to the public and is likely to stay that way for the foreseeable future. Finally there is the Harrisburg Power Dispatcher's office. Constructed in 1937 to manage the PRR's great westward electrification expansion, it remained in operation until 2012. Not only is the preserved hardware remarkable due to its age, but it is also one of the first wide area electric power SCADA systems ever installed

Amtrak's Harrisburg Power Dispatchers Office in 2008

While a Power Dispatching office isn't exactly Railroad Signaling, it is certainly in the same wheelhouse seeing as it was both essential to railroad operations and made use of very similar relay and electro-mechanical age technology.  The same Harrisburg Chapter team that restored HARRIS is now currently working to restore the Power Office after having obtained a 10 year lease from Amtrak.  From what I have been told, the office is pretty much as it was when the door was locked in 2012.  Everything is there, but the equipment was worn out after 80 years of operation and quite a bit of modification.

Amtrak's Harrisburg Power Dispatchers Office in 2008

This is in contrast to recent developments at the Baltimore Power Dispatchers Office that handled NEC electrification between Perryville, MD and Potomac Yard in Alexandria, VA. Located in the offices above Baltimore Penn Station, the office was gutted except for the large display board and other interface equipment. Unfortunately some very long term plans to convert the old PRR office space into a hotel have finally come to fruition and instead of preserving the space as an attraction, all remaining equipment will be sent to likely the B&O Museum where it will sit out of view or as a static display, devoid of context. 

Telecom type SCADA relay bank at Harrisburg PDO

Hopefully the Harrisburg PDO will be restored to the same level as HARRIS tower with simulated events and a fully working display and interface. If anyone thinks they have the skills necessary to help out please contact the Harrisburg Chapter NRHS.