The End of Main Line Pneumatic Points

There's a lot of work taking place on the former PRR Northeast Corridor these days and unfortunately it appears that the era of main line pneumatic point machines might be nearing an end. The stock of pneumatic interlockings had been dwindling for years with LANDOVER near Washington, DC, GRUNDY in Bristol, PA and FAIR in Trenton being the two latest to see wholesale conversion to electric US&S M3 style machines. Prior to that both THORN and PAOLI interlockings on the Harrisburg Line saw their pneumatics go even while their interlocking towers remained open.

Currently, what had been some of the best preserved main line pneumatic interlocking plants, RIVER and POINT at the north end of Baltimore's Bayview yard, are in the midst of an electric conversion as their turnouts are being replaced as part of a general maintenance project. 

Unfortunately, due to their location, these two locations are difficult to photograph except from the rear of passing Amfleet equipped trains.

This will leave what is in my estimation only a single intact pneumatic main line  interlocking plant, HOLMES, at Homesburg Jct in Philadelphia. OVERBROOK interlocking, with its staffed tower, is still largely pneumatic, but had seen select turnouts replaced with M3's.

 

Of course a significant number of terminal plants will remain pneumatic for the foreseeable future and one could possibly count terminal adjacent interlockings like Metra's TOWER A-2 and SEPTA's 16TH ST as Main Line as well, however neither see the high speed movements currently present at RIVER, POINT and HOLMES. The challenge for documentation is capturing the movement and sounds of the switches as they throw. At HOLMES this is most easily covered when local freights enter and exit the Buttleton branch, but this could also be achieved when tracks are out of service east or west of the plant.  Of course the easiest way to engage with pneumatic point machines is to see them on rapid transit systems such as The PATH, NYC Subway and the SEPTA Broad Street Line.

Amtrak FAIR Interlocking Loses Its Quirks

 A little while back I discussed the evolution of NORTH PHILADELPHIA interlocking from its construction in 1914 to its disestablishment in 2005. Early urban interlockings such as NORTH PHILADELPHIA were colorful characters with all sorts of extra infrastructure to handle not only the main line traffic, but also stuff like industrial switching, yard and light engine moves. FAIR tower in Trenton, NJ is not only NORTH PHILADELPHIA's sibling in appearance, but also in its arc through history. While I don't want to get too deep into the history and evolution of FAIR, I will say that it was drastically expanded in the 1930's, then entered a series of successive diets in the late PRR, Penn Central and Amtrak eras before the tower was closed around 1994.

In its second to last iteration that lasted from around 1990 to about 2020, FAIR had lost all of the double slips and freight support it had maintains up through the end of mineral traffic on the Belvidere and Delaware line. It's primary function was that of a passenger terminal for the Philly and New York area commuter services that terminated there. The two remaining quirky features were two additional tracks at the far northern and northerner limits of the right of way. Track 7 was used to store SEPTA equipment, while "North Low Track" served as an extra place to stash New York bound peak period trains overnight. Below you can see how the plant changes from its late PRR configuration to post CTEC configuration.

The area of interest is the North Low and Hill Tracks. The Hill Track used to connect with the Bordentown Secondary to Camden which saw limited passenger service like the famed Nelly Bly NYC to Atlantic City express train. In the commuter era that was used as precious storage space, keeping alive the old configuration that used to serve Doodlebugs that would run into Trenton from rural South Jersey.

 

While eastbound movements out of North Low could be made via the "Wall Track" past the tower, this involved a Restricted speed signal. The preferred option was the 86 switch protected by the 6BE and 8BE signals. This was located at the eastern end of the platform with 4 dwarf signals protecting the single low speed switch. One of the dwarfs was mounted on a striped stick for better visibility.

At the west end of the platform was another left-hand turnout, the 86W switch and associated 6BW and 8BW dwarf signals. You are seeing things right in this only allowed for North Low access from the hill track. This became an issue when around 2005 NJT opened up its Morrisville Yard west of Trenton in Pennsylvania, turning all of the terminal traffic that needed to be shuffled about into run-through traffic. Trains arriving from Morrisville could not access the North Low and as you can see from the rust, it became disused. 

Starting in 2019, Amtrak brought the rationalization hammer down on this legacy configuration. The 86W switch was reversed, the Hill Track was removed and the 16 switch from Main Track 1 was fixed up for higher speeds. Now trains from Morrisville can access the North Low, making it potentially useful again. Unfortunately the next step came with the same interlocking refresh that removed all of FAIR's pneumatic point machines. The 86 switch and its associated signals were completely removed.

Trains using North Low will now have to take the slow route past FAIR tower and them on 0 Track to HAM interlocking, but as you can see from the grass, it is unlikely there will be a need for North Low any time soon. While this all makes sense, especially in the age where efficiency is more and more important, the 86 switch and its dwarf signals are still a loss worth noting.

SEPTA Broad St Subway Signal Project

The SEPTA Broad Street Line is notable for being one of the best examples of pneumatically powered signaling appliances in the form of point machines and trip stops. The whole line is equipped with such devices except for the Fern Rock shop and yard complex, which was subjected to a re-signaling project around 2005. Well I just caught word that due to a long term plan to rebuild the City Hall station, SEPTA will be installing bi-directional signaling between the line's WALNUT and FAIRMOUNT interlockings.

Single direction signaling at WALNUT interlocking.

Since it was constructed in the late 1928 it has operated almost entirely with single direction ABS with a few isolated segments of bi-directional signaling within interlocking limits. SEPTA's plans to rebuild City Hall will take entire platforms out of service so the usual practice of closing either the local or express track will not be an option. As a result SEPTA is looking to install some bi-directional capability so the normally 4-track railroad can operate as a two track railroad between Walnut Locust and Girard stations. 

It will be interesting to see what brand of signaling equipment SEPTA decides to go with and if they stick with pneumatic trip stops or convert to electric. After the MFL was re-signaled around 2000, SEPTA was able to bank a large amount of 1980's vintage pneumatic trips and A-10 point machines that have been slowly appearing on the BSL so there might be enough in stock to supply the project. Since the wayside signal system is likely to be replaced around when new rolling stock is purchased, this would save money on an ultimately short term change. On the other hand if someone else is paying, SEPTA could decide to rid themselves of a "troublesome" technology. There could also be a mix with the existing equipment left alone and only the new reverse direction signals getting electric. Regardless, I think I might take the time to get photos of whatever is currently in place.

2024 NEC Reference Video

 A side effect of Allan Fisher's recent "Festival Express" style journey from New York to Saint Louis in a private car full of transit Youtubers was a 3 hour and 22 minute long high definition rear facing railfan video of the entire Amtrak Northeast Corridor between New York and Washington. The video was filmed from the PV's position behind Amtrak's westbound Cardinal Train 51 with no observable delays and a top speed of 110mph.

This video is an important historical artifact as it captures certain NEC elements that are under imminent threat of replacement including the PORTAL bridge and Baltimore's B&P tunnel complex as well as all of the associated signaling that will likely be part of upcoming Rule 562 expansions. I was also able to confirm some recent changes such as the replacement of the pneumatic A-5 point machines at GRUNDY interlocking with electric M3's. If you have any questions about current NEC layout, this is the resource for you.

PHOTOS: CORK Interlocking

Over the first century of its existence the vaunted Pennsylvania Railroad Main Line between Philadelphia and Harrisburg suffered from a significant design flaw around the city of Lancaster. Despite all of the grade separation and curve elimination, trains still had to navigate through Lancaster's downtown grid because when the Philadelphia and Columbia railroad was being built in 1834, the Lancaster establishment lobbied for the route to pass through downtown to better support the local economy. As the decades passed this little detour became unwieldy. A cutoff was constructed north of the city in 1888, but the vast majority of passenger trains still had to take the old route through town because that was there the station was. Finally in the 1920's the PRR had the money and opportunity to construct a state of the art station on the bypass route along with a modern interlocking plant to control the terminal area and PRR Columbia Branch junction. This would be come known as CORK interlocking, after an adjacent Crown Cork and Seal plant and is the next in my deep dives into PRR Main Line interlocking towers.

Opening at the same time as the station in 1929, CORK was a rare, for North America, direct wire area interlocking with an end-to-end length of 3.3 miles. For comparison the sprawling ZOO interlocking in Philadelphia is only about 1.7 miles between its extreme points. Controlled from a relatively modest 67 lever US&S Model 14 interlocking machine, the CORK plant consisted of 4 distinct sections. From east to west there was the "Conestoga" section where 4 tracks converged into 2 and the old line downtown diverged, the east end of the station, the west end of the and Columbia Branch junction, the diamond crossing of the Reading Lancaster Branch over the PRR Columbia Branch and finally the crossing of the same over the PRR Main Line proper. Additionally, CORK had a plethora of interlocked hand throw switches serving local industry scattered along its length.

CORK went through four distinct phases in its layout. The initial 1929 configuration, pictured above, had 4 main track to the east, 4 main tracks in the station area and the full compliment of station support tracks. On or after 1948, track #3 to the east was removed and this marks the second configuration.

Sometime around 1960, as seen above, the PRR implemented a significant rationalization with track #2 to the east also being removed and significant cuts being made to the station terminal support tracks. The final Amtrak era configuration, seen below, saw the end of through/electrified freight operations along with the Reading Lancaster branch and resulted in the removal of Columbia Branch portion of the interlocking plant.

Starting at the extreme eastern end of the territory we find the Conestoga section, likely named for an earlier tower covering the New Holland Branch and the squeeze from quad to double track to pass over the Conestoga Creek viaduct that the PRR never bothered to widen. The Main Line was 4-track to this point until 1948 when either track 2 or 3 was removed as most through freight could be accommodated on the A&S Low Grade Line branching off at Parkesburg. In 1929 Main Line at this point was ABS Rule 251 so all reverse direction movements would be provided with dwarf signals. The old 4-track beam gantry carries the remaining 2R signal with the 4R dwarf on the ground. It is currently not clear if the post 1948 third track was bi-directional or a second ABS track in the direction best able to support slow freight trains on the Main Line's infamous grades.

The ~1960 reconfigured Conestoga section saw the addition of a trailing point crossover set adjacent to the lever 16 locked New Holland Branch connection. Possibly intended to allow eastbound trains to use the eastbound platform or something with local movements, the #1 crossover was not very useful in the Amtrak era with typically rusty rails and the overhead catenary removed. The "hacked" nature of the #1 crossover is evident from the dual level westbound dwarf signal that is cleared by the 4R with #1 normal and 2R with #1 reverse. When CORK was rebuilt, the New Holland Branch switch was upgraded to power operation, which would have required additional modifications to the CORK Model 14's logic in the 2007 time frame.

The west end of the Conestoga section is located west of the viaduct at the point where the old alignment would veer south towards the downtown. In the 1929 configuration this would be the east end of a second stretch of 4-track main line running from the Conestoga section through the Lancaster Station proper with tracks 1 and 4 having interlocked hand throw industrial leads. The intent appears to minimize the conflicts between freight and passenger trains east of the station. After 1960 the need for 4 main tracks in this area was eliminated so both tracks 1 and 4 west of Conestoga were relabeled as Ewd and Wwd Station Tracks with the eastern 5700 feet of the old track #4/Wwd Station converted into an industrial lead and the #5 switch removed.

Although labeled a "station track", the eastern part of the old #1 track to the 20L still had up to 8 hand throw industrial spurs locked by the 30 lever so trains stopping at Lancaster would likely return immediately to track #1 via the #11 crossover. Later, the #7 switch would be reduced to slow speed operation as evidenced by the lack of medium speed route on the 20L on the far right of the signal bridge shown below. Entrance into the Conestoga section was governed by the 6L high signal on the post-1948 track #1 and the 2L dwarf on post-1948 track #2.

A mile to the west we encounter the station terminal area. As a clean sheet modern design, the Lancaster station was equipped with high level platforms that avoided issues with freight clearance via the provision of two non-platformed through tracks like Trenton and North Philadelphia. In the 1929 configuration each island platform supported 2 tracks, a main track and an additional station track numbered A and B. On the southern side of the station and additional through freight track numbered 0 could carry eastbound Columbia Branch freights and a further Express Track served Lancaster Station's dedicated high level mail and express platform. A further mail/express/engine stub track was built into the west end of the westbound platform.

After the 1950's both tracks A and B were removed along with the westbound stub track. From then on the east station section of CORK featured the #15 switch from track #2 onto the westward station track and a facing point ladder from track #2, through track #1 to access the eastward station track and #0 express track. Westbound movements were governed by the 10R high signal and the 12R and 14R dwarfs.

Starting in 2005, the east end of the station would be reconfigured for the final time with a full crossover in conjunction with the removal of both station tracks. Here in this 2005 photo from the east end of the westbound platform you can still get the jist of the PRR layout.

Eastbound trains on the old station track would be governed by the 14L high signal that also allowed for straight routes to the extension. With the end of through freight, the center track #1 and #2 saw little use in the late Amtrak era and when the Harrisburg Line was reconstructed in the 2000's the station tracks were removed and the main tracks ultimately relocated to serve the high level platforms. 

THORN Goes on a Diet and Other Pneumatic News

Since I last visited THRON interlocking on Amtrak's Harrisburg Line, more progress has been made towards rationalizing the interlocking and closing the tower. Similar to what has taken place at PAOLI, redundant crossovers and stub tracks have been removed, although it is still not clear what the final outcome will be as SEPTA service looks to expand back to Coatsville and Parkesburg. 

As recently as 2019 THORN was still in an approximation of its 1970's configuration with a 6-track full crossover and stub tracks for the old Trenton Cuttoff, removed track #3 in both directions and the #6 yard track. You can see my video post on an operator setting up a typical SEPTA R5 local movement across the entire plant.

However since then Amtrak has removed the worst of the redundancies with the 53 turnout and 55 crossover being completely removed, the 49, 51, 57 and 61 crossovers being reduced to turnouts, track #3 being removed in its entirely along with most of track #6 and the through section of track #5. Perhaps most significantly the interlocking has been completely converted to electric point machines, despite new A-5 point machines being installed on the #41 and #43 crossovers in 2019. You can browse the current state of the interlocking here. 

Elsewhere on the pneumatic front, OVERBROOK interlocking has seen continued attrition of its A-5 point machines with as few as 3, the #11, #15 and #19, remaining in service. The casualty list includes the 019 switch in the former Woodbine section of the plant.

After PAOLI's conversion a few years ago, this leaves ZOO interlocking as the only intact pneumatic interlocking plant on the Harrisburg Line.

Caught on Camera: Bastard A-5

While getting photos around the JO section of ZOO interlocking I noticed some interesting writing on the A-5 pneumatic point machine attached to the 131 switch.

In stenciling the signaling department appears to have labeled the point machine as a "bastard". Someone else, perhaps another employee, perhaps a local, has expanded upon this with "/whore". Given that the points appear to show evidence of a recent rebuild, it is possible that this A-5 has been assembled from the parts of others or contain a non-standard modification. I believe that A-5's have a notion of handedness that could be at play here. If whatever the modification was not entirely successful that could have resulted in the editorial comment.

Amtrak Pneumatic News

On the southern end of the NEC two increasingly rare interlockings with US&S A-5 pneumatic point machines are facing their final weeks or months.  The first is PAUL interlocking, formerly UNION JCT at the northern end of Baltimore Penn Station. The plant, with 11 switches, is slated for reconstruction as part of a larger Penn Station redevelopment project that will see the construction of a new platform and the relocation of station operations from the historic 1911 structure to a new Amshack across the right of way.  The existing building will then be converted into a hotel. The new platform is progressing rapidly and new pre-fab turnouts with the new M3 electric machines are on site.

The interlocking on the south side of the station, CHARLES, was converted to electric point machines a bit over 20 years ago.

A bit closer to Washington, DC, the new HANSON interlocking project intended to replace the existing LANDOVER interlocking is also nearing some kind of completion after nearly 3 years of construction.  The new 3 track crossover is located just north of the existing LANDOVER plant and will provide access to track #1 south of the New Carrollton Station as well as some additional 80mph high speed crossover moves.  The good news is that LANDOVER interlocking will remain, but the bad news is that it will only cover the current 91 switch combining the 1F and 2F Landover Line tracks. All 5 pneumatic point machines will be retired.

Both of these interlockings are challenging to document due to overhead bridges with catenary shields. Any plans to do so should likely be done quickly.

NASSAU Tower - Gone But Not Forgotten

You may recall that some years ago I was sounding the alarm about the pending demolition of NASSAU tower in Mineola, Long Island. Well, New York being completely dysfunctional, the demolition to make way for the LIRR Main Line Third Track project took far longer than anticipated, eventually taking place sometime between August 2021. The demolition was just in time for the complete collapse of peak-period commuter travel in the NYC area rendering the third track capacity expansion completely unnecessary (😢). 

NASSAU interlocking, sans Tower, February 2022.

Anyway as the third track megaproject continues to creep forward, someone spotted NASSAU's late model interlocking panel dumped out back near some storage containers. It was unclear that the fate of this artifact was to be, as in museum preservation, scrapping, theft or vanishing into a railroader's basement, however it is worth checking out for any signal fans who happen to live in the area (and who might own a truck and some high visibility vests, wink wink).

Apparently this panel type interface was replaced by a VDU late in the tower's existence as plans were carried out for the transfer of operations to the Jamaica dispatching center as was done with QUEENS tower a few years ago. Thanks to multiple visits to the tower while it was in service along with some contributed interior photos I plan to post a more complete retrospecting on NASSAU tower in the near future, so stay tuned for that. 

In other news the pneumatic movable point diamond at the NASSAU flat junction has been removed. A major maintenance headache, the diamond has been replaced by a second Oyster Bay switch onto main track one, creating a bottleneck by forcing all Oyster Bay trains to platform on the westbound local platform. 

You can see the new configuration in the LIRR Main Line 3rd Track plan.

This type of 2-tracks into 1-track configuration is extremely rare as it doubles the chance of a switch failure impacting main line traffic compared with merging both branch tracks before a single main track switch. This will also end of ritual of inbound and outbound Oyster Bay train passing eachother at NASSAU to minimize impacts to Main Line service. The ideal solution would have been a two track flat junction using full turnouts and a mid-platform signal on the new eastbound track 3. That would have allow for the option to use both platforms if extended wrong running on track #1 was not available.

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.