CSX Files to Discontinue Cab Signaling on RF&P

Virginia has become somewhat of a purple state both in its politics and its approach to higher speed passenger rail. Recently the state spent billions to purchase a number of key rail lines from CSX to grow service on the DC to Richmond to Raleigh corridor that already sees a significant amount of Amtrak service. From the outset it appeared that Virginia would begin to resemble New York or Pennsylvania with their own NEC adjacent 110mph intercity services and allied commuter rail. Unfortunately CSX's filing on December 23rd to abandon the RF&P cab signaling system (CSS) is threatening to upend these higher speed plans and, unfortunately, the State of Virginia appears to be on board.



As the wireless ETMS PTC system has come online across the country, the Class 1 carriers first moved to abandon their legacy safety systems such as the ex-Santa Fe IIATS and the CNW's legacy 2-aspect cab signaling. This was neither surprising nor controversial due to each system's rather limited capabilities and general lack of industry support. However Union Pacific then filed to discontinue its substantial coded track circuit based Automatic Cab Signaling system claiming that ETMS was a preferable substitute. Saving the accuracy of that assertion for later, UP-ASC did have a number of limitations that made it more difficult to integrate with ETMS the way NS had during its 2016-2018 PRR territory re-signaling project.

Union Pacific Cab with ATC / ASC Display

Left out of these moves was CSX, which was generally free of legacy systems except for former Conrail cab signals on the rather isolated Boston and Hudson Lines and the RF&P cab signals (changed to the Conrail/PRR standard) between Washington and Richmond. Although CSX filed to discontinue the in-cab ATC function in 2020, this was superfluous due to ETMS PTC. Then in late 2021 the other shoe dropped with CSX filing a petition with the FRA to completely discontinue and remove CSS using PTC as an excuse and the real shocker is that Amtrak, VRE Commuter Rail and the State of Virginia have signed onto the application as well.

Cab signal antenna behind the pilot of VRE MP36PH-3C #V50

The RF&P CSS forces CSX to cab signal equip a large portion of its locomotive speed so CSX wanting to rid itself of this headache is no surprise. Fear of cab signals is why CSX chose to force a SEPTA-ration of the Trenton Line with the SEPTA Fox Chase and West Trenton services. However getting VRE and Amtrak to sign on is a bit more of a puzzle because of the long term implications, however in the short term VRE would get out of the cab signal business and Amtrak would get to avoid a possible failure and inspection point on every diesel powered train heading out of DC except the Capitol Limited. The filing also mentions that having both CSS/ATC and ETMS active causes some issues for the crews as they have to pay attention to both systems as the CSS/ATC tends to be a bit more restrictive and, at as late as 2011, that would include dropping the cab to Restricting for Medium speed movements within interlocking limits.

Another point in the filing was CSX having to maintain mid-block CSS repeaters and code change points. Although when used for the purposes of CTC, pulse coded track circuits appear to be fine for block lengths of 2 or 3 miles, on CSS equipped lines, the cab signals appear to need repeaters spaced about every mile. I suspect the reason is due to the need for lower power pulse codes that prevent code energy burning through the circuit shunting action of the train axles . In addition to the repeaters it was common practice to put code change points in advance of absolute signals to drop an Approach cab to Restricting about 1500 to 3000 feet in advance of a stop signal. In the 1980's Conrail started using the repeaters to drop cabs in front automatic signals as well and SEPTA picked up that practice for use on the short blocks on the reading viaduct.   The diagrams provided in the appendix of the the regulatory filing show cut points between intermediate signals that are only 1 mile apart and also refer to them exclusively as cab signal cuts, so it is safe to assume that when the RF&P re-signaled in the 1980's they adopted the practice of dropping cabs in advance of Stop and Proceed intermediate signals as well.

RF&P CSS code change point at Milepost 24.1

So what's the problem? Why should one care beyond some sort of cab signal nostalgia?

1. ETMS is not a cab signaling system and it is unclear if it ever will be or if that is even desirable.
   
   
2. CSS increases capacity and provides concrete safety benefits that ETMS does not.
   
   
3. CSS powered ACSES PTC provides a clearer path to 110 and 125mph operation.
   
   
4. CSS is more resilient. 
   

Let's go over these point by point. First, ETMS with all of its wireless communications, track profile databases and complicated computing power avoided a lot of hard technological and security issues by acting as a safety overlay instead of a signal system. This means it slows trains down, but doesn't speed them up. By rule ETMS fails safe because crews continue to follow the legacy rulebook and signals. Doesn't matter if the out of state PTC server gets hacked because by rule cannot rely on it to provide speed or signal information. It's the difference between adaptive emergency braking and Tesla autopilot. Of course people are making waves about using ETMS as a cab signal system or as a full on CBTC system and it might even get approved (like the 737 MAX got approved), but just remember it is going to have the same problems as voting software.

Second, CSS provides partial moving block functionality that allows for mid-block upgrades as block state is continuously fed to the train via the secure communications channel of the rails. Moreover, those extra cab signal repeaters CSX wants to get rid of can be instead used to provide DOUBLE the number of signal blocks! This is effectively what NS did on its former Conrail territory eliminating automatic wayside signals and creating code change points every mile. The RF&P on he other hand will be left with half the number of fixed signal locations that will need to be physically re-positioned to respond to capacity constraints or higher speeds. In terms of safety, CSS codes are transmitted through the rails. If a rail brakes or anything else suddenly disrupts the track circuit, an approaching train will see a signal drop immediately. ETMS only sees what the signal system sees, a block occupied by...something.



Third, ACSES is Amtrak's transponder and CSS based PTC system that is available off the shelf for speeds up to 150mph. Right now Amtrak is trying to get ETMS certified for 110 in a "couple of years". ACSES is far simpler to set up with no need to download track databases and both CSS and ACSES operate and expanding Rule 562-ACSES south to Richmond and Manassas would unify Virginia passenger rail with those of the entire northeast. 

Rule 562-A Signal Bridge at BERLIN at 100mph.

Fourth, CSS just works. The technology was developed in the 1920's and can be run with a couple of relays. There is no wireless data link that can be disrupted or hacked. Although NS uses ETMS on its former PRR territory, it does not need to maintain a constant wireless link with trains between blocks because cab signal codes are proof of movement authority (as evidences by the presence of PTC antennas only at interlockings). When deployed with ACSES, CSS and ACSES are independent systems that can each function if the other fails. Currently FRA regulations require a 60mph speed restriction for trains operating with failed PTC, however the limit is 80mph if ATC is present. These 60mph PTC failure restrictions are not a rare occurrence and on the 110mph Michigan Line this will impart 30 to 60 minutes of delay. The freight railroads don't care about a 60mph limit because that's as fast as their trains go. 

Cab Signal equipment box on a Geep

In summary, discontinuing the RF&P CSS is a massive failure of imagination that will lock the Virginia services into a second tier, freight centric method of operation for decades. It will reduce capacity, and increase service disruptions just to save a little money and hassle in the short term. I've linked the regulatory motion. If there's a way to leave a public comment try to do so and if you know of any advocacy groups that might be in a position to do something, please bring this to their attention. The ultimate shame is that the proper response to accidents such as Chatworth would have been a nation-wide cab signaling requirement.  Cheap, simple, effective.  Instead the only winners are signal vendors and those that stand to gain from a hobbled rail sector.

Caught on Camera: Amtrak's Two Indication Block Signals?

 Twice in the last year I have had the fortune to catch and video the strange situation of Amtrak intermediate signals transitioning directly from Stop and Proceed to Clear.  The first was at the 592 automatic on track #1 eastbound at Irishtown Road, part of the ~2006 Rule 562 CTC project, after the passage of the eastbound Train 42 Pennsylvanian.  The second instance was at the 133 automatic on track #4 westbound in Radnor, PA, an origional PRR signal dating from at least 1948, after the passage of a westbound SEPTA local. 

This effect is not universal so I don't think Amtrak has gone around systematically eliminating the Approach indication for "safety" reasons (although I wouldn't put it past them) so my best guess is that the 75ppm code generator at the next signal location down the line has failed resulting in the featured locations seeing a 0 code for an occupied block. Because train traffic hasn't been busy enough for one train to be running behind another, I suspect that in both cases the defects had simply not been noticed/reported.

133 Year Old BO Tower in Kalamazoo (Finally) Demolished

The demolition of some towers, like Fostoria's JACKSON ST, come as a surprise.  On the other hand other tower are clearly on the pah to the wrecking ball and it is not a matter of "if" but "when" and the former Michigan Central's BO tower in Kalamazoo was most definitely in the later category.  In operation for a mind boggling 128, a history of the tower was discussed in my post covering its closure back in 2016. Although BO was owned by Amtrak and/or the State of Michigan as part of the Wolverine Corridor, at the time when the door was locked and boards went up on the windows, it was mentioned that the interior equipment like the model board and interlocking frame were destined for the Henry Ford museum in Detroit.  This is when it became clear that there were no serious efforts underway to preserve BO tower.  

Honestly I would have been surprised if there were.  The tower was built in 1888 and constructed of wood.  It would have needed a pretty serious preservation effort to keep it intact (although the roof was replaced in 2006).  Second, the tower could not be preserved in situ as it was just feet from TWO active tracks, one an Amtrak route with multiple daily train movements.  Third, unattended wooden structures in an urban area catch fire, full stop.  See what happened to SHORE tower just a few months ago.  Fourth, there was no obvious rail museum to relocate the tower to in the immediate area.  Finally, the removal of the interlocking frame (if it was actually removed) would have fatally compromised the structure.  Remember, preservationists tried to move MO tower in Cresson, PA but it was just too weak and immediately fell apart. All of these factors working together sealed BO tower's fate.

Preserving BO tower would not have been beyond the pale.  Tower B-12 in Franklin Park is pretty much the same type of structure and was moved to a nearby park, but it does not seem that Kalamazoo has the enthusiast community on hand to take on such a project. Kalamazoo, where my maternal grandmother is actually from, is still part of the rust belt and there just isn't a lot of downtown civic energy available for these types of projects. Because of my family connection I will be certain to visit Kalamazoo in the upcoming years.  It's a shame BO tower will not be there waiting for me.

UPDATE: According to this video, the lever frame in BO tower was NOT preserved and was generally ripped up in the demolition process.  Not sure if it went to a scrap yard or if a collector was able to snag it. It also appears that there was a limited preservation effort that ultimately failed.

Fostoria's Historic JACKSON ST Tower Demolished

 JACKSON ST tower, located in Fostoria, Ohio, may not be as well known as the famous tower located at the Iron Triangle, but JACKSON ST was notable for hosting the world's first CTC system installed in 1927. As described in this article, the CTC system from General Railway Signaling (GRS) covered 40 miles of New York Central trackage and was the first time trains had been directed on a single track with passing sidings entirely by signal indication and without any use of train orders. 

If you are wondering what a New York Central tower is doing in a town known for the B&O, C&O and N&W, that's because the NYC line between Toledo and Bucyrus was almost completely abandoned.  While JACKSON ST wound up just a short distance from the CSX owned C&O Northern Branch to Toledo, it was still guardian an empty right of way and may have been assumed to be off current railroad property all together.  

Well it turns out it was still owned by CSX and despite the tower's good condition and historic importance, it was demolished sometime in the fall. I'm pretty sure the actual CTC panel was preserved, but its a shame that places like Fostoria likely lack a critical mass of rail enthusiasts or preservationists to prevent this kind of destruction.

Explore French Signaling on the Aubrac Line

 A short while ago, a video on the least used passenger rail station in all of France piqued my interest in the Aubrac Line between Beziers in the south of France and Clermont near the center.  The mountainous line was electrified with 1500v DC in the 1920's and retains much of its original electrification infrastructure including catenary supports and substation buildings.  The line is a good way to see how French railway signaling works in practice as much of the line is single track running under manual block operation with 5-10 mile blocks between stations that also serve as passing points.  Some of the cities along the line night have some shorter automatic blocks so there is some variety.  

The line is also equipped with Le Crocodile ATS system and the more modern KVB balise based system, which is interesting.  Because of the manual block and long gaps between passing points, things can get a bit dull at times, but aside from looking for the 1500v DC substations one can try to figure out if the line uses track circuits or axle counters for train detection.

 In general, the library of cab view videos from Europe is far more extensive than those from the US.  This might be due to the larger number of rail workers and single person operation that limits snitching. Whatever the reasons, its a great resource to help learn other signaling systems.

 

Coal Country Signaling Hit Hard by Declining Traffic

 Early this year the perils facing the extensive rail infrastructure in the eastern coal region were brought to light then NS threatened to remove the signaling from a number of coal dependent lines in its territory.  While many of those applications were withdrawn, according to a recent article, it seems that CSX is also working on downsizing its coal related infrastructure.

Siding removal on the C&O Signaled Coal Creek Sub

This is likely to affect lines that CSX had previously declined to put attitudinal investment into due to the anticipation of a drop in coal traffic.  While this had the positive effect of preserving the C&O signaling and/or the C&O aspect system, at some point the bill will come due and either the signaling or the entire line will be abandoned.

Unfortunately the cutbacks are also affecting lines CSX did spend the money to re-signal, but in these cases taking double track segments, sidings and other pieces of the physical plant out of service.  This specifically applies to the former C&O main line from Richmond to Cincinatti that was re-signaled without much in the way of rationalization between 2010 and 2014.  While the C&O signals were removed, quite a bit of interesting signaling remained with back to back interlockings and other oddball layouts.  The phantom rationalization will reduce signaling locations and possible signal indications, although the low traffic levels will also do a lot to limit what a signal fan might happen to run into.  Amtrak's Cardinal runs along this route and I'd promote taking it if a baggage car wasn't currently strapped to the rear.

Although highly detailed documentation of modern signal locations isn't a good use of time, it is often still worthwhile performing a basic documentation just in case these sort of economic factors come into play.

PHOTOS: NORTH PHILADELPHIA Tower

In my previous post, I covered the history of NORTH PHILADELPHIA Interlocking and Tower that were constructed as part of a 1915 improvement project to build a brand new main line passenger station at what had been known as Germantown Junction on the PRR's Connecting Railway. In this follow-up article I will cover the tower itself and its interior as they stood on the eve of closure in 2005 after 90 years of service.


Although the adjacent North Philadelphia station itself is described as being designed in the Châteauesque style, NORTH PHILADELPHIA tower itself is more in line with UNION JCT and B&P JCT towers that were built as part of the Beaux-Arts Baltimore Penn Station project of 1911. From the outside NORTH PHILADELPHIA appeared to be an identical twin of FAIR tower located 30 miles to the north in in Trenton. However despite having been built at the same time, FAIR utilized an electro-mechanical US&S Style P interlocking machine, an example of railroads in this period hedging their bets in regards to purely power operated interlocking plants. Although both FAIR and NORTH PHILADELPHOIA interlockings served stations with high level platforms, station tracks and a double slip ladder, NORTH PHILADELPGIA would stay in service a decade longer, despite FAIR having its Style P machine replaced by a spiffy Model 14 in the 1930's. It would also avoid FAIR's severe case of "tower window syndrome".

As documented in a period article in the journal Railway Signaling, NORTH PHILADELPHIA was state of the art with an all electric Union Switch and Signal Model F interlocking machine, illuminated model board and glass encased route locking cancellation timers.



As I detailed in the previous post, NORTH PHILADELPHIA's interlocking plant would see many changes over the years, including a change from electric to pneumatic switch operation, but despite all this the tower retained its original 47-lever Model F interlocking machine. The photo below has captured the NORTH PHILADELPHIA machine in its late 90's configuration with former 0 Track at the top separated as the Conrail Trenton Line, but the other freight and station tracks still present.  Also note the east end's trailing point ladder and the Chestnut Hill Branch crossover.  That crossover was a later addition and we can see how it necessitated re-drawing the Chestnut Hill Branch horizontally along the bottom of the model board when comparing with the 1915 photo above.  We can see the Rule 251 between here and SHORE via the 835 and 844 single direction automatic signals.  Makes you wonder if an operator was ever able to arrange a movement from #1 track to #1 track via #5 track through the station. 🤣

Skipping ahead to 2005 we can really see just how much was removed before the tower was closed. Compared with the 90's photo many of the upwards pointing switch levers on the left of the machine are out of service with their numbers missing. Although similar to the more refined Model 14 in operation, NORTH PHILADELPHIA's Model F featured a glass top, to ensure the full employment of signal maintainers, and a row of cast lever indication lamps instead of the later Model 14's use of stamped sheet metal. Other changes from the 1915 depiction include the removal of the electric switch amp meter and additional rundown timers to prevent delays at peak times if routes needed to be changed. In fact the provision of a clockwork rundown timer for practically each signal lever was almost unheard of luxury in the industry, which speaks to the financial resources of the PRR.  In the 2005 photo red tape with updated rundown times have been placed on the timer globes, perhaps indicating that the various signal changes on either side of the legacy plant required the times to be updated.

On the right side of the main machine we see the train announcement bell and higher numbered levers.

On the left side of the main machine we find the lower numbered levers along with the 4-lever table interlocking machine for the Chestnut Hill branch crossover supporting levers 50 through 53. Note the amount of space in this tower on either side of the lever frame which explains how FAIR tower was able to support a 75-lever Model 14 in the same physical space.

On the right side of the model board we can get a somewhat closer view of the changes that took place between 1999 and 2003. The gold stenciled labels on the board are original with the hand painted white and yellow indicating modifications. Removed portions have blacked out with paint, however most of the previous layout along with some labeling can still be seen. All four tracks to the west were bi-directional Rule 261 starting in the PRR era, but dedicated traffic levers were not provided at either NORTH PHILADELPHIA or ZOO. The red lamps at the bottom indicate which signals were currently displayed for train movements (in this case the 28R for one on track #3 west). There is also the west end low air warnings with lamps to 45psi and 20psi and a dragging equipment detector (DED) reset panel for DED's on eastbound tracks #1 and #2.

As of mid-2003 the entire east end of the plant was remoted to CTEC Section 6 as CLEARFIELD interlocking and was literally wiped off the model board despite physically occupying the same space. Because the east end no longer exists, displayed signal lamps have had the labels painted over and track indication lamps have been largely removed except approach lamps on tracks #3 and #4, which likely still give some reasonable degree of warning that a train is heading west from SHORE. Mirroring the west end we see an east end low air alarm as well as DED resets for westbound movements on tracks #3 and #4. Also missing is the 53 trailing crossover on the Chestnut Hill Branch.

The 10, 12, 14 and 16 signal levers previously controlled all main line signals through the east end and were repurposed as traffic levers as the simplest way to integrate the old 1915 mechanical interlocking logic on the west side with the modern interlocking on the east end. Observing the #14 lever lit for a westbound movement on track 3, appears that these levers must be operated for each movement, just like they had as signals, otherwise no direction of traffic is set.

US&S CTC With Coded Track Circuits

 For years I have been aware of a major split in how Traffic Control systems function at a technical level. In the US&S corner is the "traffic lever" system where segments of track have a set current of traffic set by a figurative traffic control lever. In the General Railway Signal corner is a different system where intermediate signals can float in both directions once a train has passed and if no following movements are routed. In an effort to get to the bottom of how these two systems worked I purchased the GSR Elements of Railway Signaling book, but as I mentioned in my review the book somehow failed to provide any real insight.



Fortunately, while searching for information on the PRR's BRADY tower on the Allegheny Valley Branch near Brady, PA, I stumbled upon a Railway Signaling Journal article on the 1944 BRADY CTC project and its use of coded track circuits, which are the same kind used in PRR/US&S cab signaling. This article not only explained why the US&S system worked the way it did, but also a number of other observations I had made over the years, such as intermediate signal locations suddenly springing to life when a route was established.

The key insight to this system is that when a track segment between two interlocking is idle, a steady flow of current is transmitted in the direction of traffic, similar to a 2600hz idle tone in old long distance trunks. Intermediate signal locations pass along this steady current until it reaches the next interlocking location that the logic interprets as the track segment being unoccupied. A request to route a train terminates the steady current at the near end and when the far end sees the energy turn off, it begins to transmit the 75, 120 or 180 pulse per minute track circuit codes we all known and love towards the near interlocking. These codes then propagate through the intermediate locations, setting the directional relays and illuminating the signal lamps and activating code generators to pass the block state on to the next signal location. When the near interlocking sees these track circuit codes it is able to display an appropriate signal.



If no following movements are planned, the near interlocking will once again transmit steady current into the track segment in the direction of traffic set by the CTC system. Intermediate signals will continue to transmit block state codes in accordance to their directional relay until they detect the steady current, at which point the directional relay is reset and the active elements of the intermediate location (signal lamps and code generators) will be turned off. Changing flow of traffic via a literal or figurative traffic lever will determine which interlocking at either end of the track segment is transmitting the steady current idle signal. This system is extra clever because in addition to not needing to transmit block state via a pole line, it is also fail-safe as any disruption in any track circuit in the track segment will register the occupancy on the CTC console.

 
These details explain a number of observed behaviors such as the aforementioned signal location on the US&S signaled Bessemer and Lake Erie springing to life suddenly when a route was established or the intermediates on the Port Road having the reverse direction dark.  Either way it also explains why traffic control on these systems are so liable to "get stuck" and why such a situation can be a headache to resolve. Even in CTC systems where the observed behavior is different, such as continuously operating signal lamps and/or cab signal code, steady current messaging can still provide a simple mechanism to flip intermediate directional relays and establish directionality.

I urge everyone to read the primary source on this topic.  It might take a few reads to get the finer points, but its leaps and bounds more approachable than the Elements of Signaling book.

What Infrastructure Spending Means

 The new trillion dollar infrastructure package will likely have an impact on that I will call "interesting signaling", I suspect mostly by replacing it, but in a few cases adding in stuff that wasn't there before. We've been through this before with the 2008 infrastructure package trickling down to various rail projects such as the New Jersey NEC modernization that brought in Rule 562 signaling between HAM and COUNTY.

Take the New York Penn Gateway project.  The connections to the new tunnel could be built as part of the existing pneumatic point machine plant, it could be built seperate from it, but leave the existing plant alone...or it could result in the whole Penn Station getting electric M3's.  

For good or for ill the PTC push has pretty much decimated signaling across the board.  What am I most worried about with the new infrastructure money?  Well a complete NEC rebuild would eliminate the remaining pneumatic plants and  intermediate PL signals.  NJT, METRA, SEPTA and the LIRR also have a number of more vintage signaling elements that have hung around due to a lack of funding. The good news is that it feels that bigger ticket items will be the target of this money as signal modernization might have a limited ability to surge (or not as the PTC push is over) and is not as critical. 

The position examples include things like the Glassboro, NJ line or other light rail projects that would use somewhat oddball signaling like IIATS or Westcab train stops.  There are also plans to restore passenger service to places like Allentown or Scranton that might see not only an expansion of Rule 562 cab signaled CTC, but also target type signals, especially in the northeast. All in all its a mixed bag and only time will tell.

PHOTOS: NORTH PHILADELPHIA Interlocking

NORTH PHILADELPHIA is an interlocking emblematic of Philadelphia's industrial strength and the Pennsylvania Railroad's wealth and technical leadership. NORTH PHILADELPHIA is an interlocking emblematic of Philadelphia's industrial decline and Amtrak's chronic lack of funds. NORTH PHILADELPHIA is not an interlocking, and is barely a station. All of these statements were at one point true and thus track the up and down fortunes of the PRR's third great tower in the Philadelphia terminal area. Constructed in 1914 on the Connecting Railway that linked the PRR's East-West Main Line at Zoo Junction to the Philadelphia and Trenton railroad at Frankford Jct, NORTH PHILADELPHIA was a direct sibling to FAIR tower in Trenton and similar in style to UNION JCT and B&P JCT towers in Baltimore and was built to control the important North Philadelphia station complex along with the junction with the lucrative Chestnut Hill suburban branch. In this the first part of a two part series we will look at the layout and history of NORTH PHILADELPHIA interlocking before moving inside the tower in part 2.

As built in 1914, the North Philadelphia interlocking complex comprised a laundry list of "thoroughly modern" and "high tech" transportation concepts. The station featured 12-car 48" high level platforms designed to seamless transfer for passengers on long distance through trains to access downtown Philadelphia without those premier trains needing to make a costly stop at the stub end Broad Street Station. All of this was controlled by a 47-lever Union Switch and Signal Model F all-electric interlocking machine with a lighted diagram and multiple clockwork rundown timers to prevent delays. The entire 1915 rebuild project also coincided with the suburban electrification project that would bring 11kv 25hz overhead wires to Chestnut Hill. 

The interlocking consisted of a trailing point ladder on the east end and a facing point ladder on the west end that doubled as a two-track into six-track flat junction for Chestnut Hill suburban trains. Between these two ladders were crossovers that allowed access to the additional station platform tracks. The tracks were arranged such that through freight trains would use center main tracks 2 and 3 unencumbered by the high level platforms, the outer passenger tracks 1 and 4 would split in to at each high level island allowing express trains to pass platformed locals and a pair of yard tracks, 0 and 5, running on each edge of the right of way to service local industry. Lever numbers ran from east to west and the facing point ladder on the west also featured a pair of double slip switches across tracks 2 and 3 as well as a diamond where the #5 freight track crossed the outbound Chestnut Hill track. Due to a tight curve on the Chestnut Hill suburban tracks, slow speed (15mph) routes for those movements was seen as acceptable. 

Main Line electrification to Trenton arrived in 1930 and with it North Philadelphia saw a number of significant upgrades. Chief among these was the application of Pennsylvania Railroad position light signaling and with it the iconic 10-track signal bridge at the western end of the island platforms (although due to the use of single direction signaling only four signals were actually mounted on said gantry) along with older style dwarfs.



Switches were changed from electric to pneumatic operation and two additional crossovers were added (using spare levers #1 and #2) at the eastern end of the platforms to allow trains their choice of center or edge tracks as express passenger trains made increasing use of the center "freight" tracks. On the interlocking machine electric switch amp-meters were removed and additional rundown timers were added since this era of interlocking did not support zoned timers. On the Chestnut Hill branch a trailing point crossover was added just north of the platforms protected by a pair of signals on each track. Without room on the large Type F frame, the new crossover was accommodated on an adjacent 4-lever US&S table interlocker. Finally, some #20 (45mph) turnouts were added, but no Limited speed routes were provided for.

The post war period could likely be considered peak North Philadelphia as in the following decades industrial retreat combined with white flight turned a vibrant middle and working class community into a marquee example of urban decay on par with the Bronx and South Central. Not only did the East-West long distance trains that made North Philadelphia a vital transfer point evaporate, but the local ridership also plummeted due to the aforementioned neighborhood collapse. The freight services were also in disarray with the Penn Central imploding into Conrail and Amtrak taking charge of the Northeast Corridor route that was still configured in the manner of the combined passenger-freight operations of the PRR era. With funding from Regan's Washington in short supply the 1992 edition of NORTH PHILADELPHIA looked surprisingly like the 1972 version with only the #1, #2 and #29 station track access switches removed and the two double slips re-aligned into coventional turnouts.

Regardless it was hard to deny that NORTH PHILADELPHIA was over-built and many of the freight tracks and sidings were falling into weedy decay.

The early 1990's would see a huge push by Conrail and Amtrak to disentangle their operations on the former PRR. Via a new connection at the Reading's old Park Jct, the Conrail Trenton Line would take the place of the old #5 track through NORTH PHILADELPHIA interlocking with the deletion of the #45 and #5 switches and associated signals. Around 2000 Amtrak finally scrapped together enough funding to begin their NORTH PHILADELPHIA modernization effort.

The over the course of a couple years the entire east end of the interlocking save for the #11 and #17 crossovers was removed and reestablished as a new interlocking named CLEARFIELD, remote to the CTEC dispatching office effective 2003.

Amtrak CLEARFIELD interlocking crossovers looking westbound.

Moreover the antiquated station track system was remedied via a wholesale track re-alignment with "Eastward Station" being through routed as Track #1, Track #2 being cut between the #47 and #17 switches, and a new Track #2 being routed along the eastbound platform. This left a rusting portion of concrete tied NEC track on the old track #2 alignment for a number of years after. 

Former track #2, removed and relocated.

Finally both the Westbound Station and 0 tracks north of the westbound platform were removed at the 32R and 34R signals. 

At this point NORTH PHILADELPHIA entered its most awkward phase of existence as a black hole on the dispatch board generally only able to participate in moving R8 SEPTA trains on and off the Chestnut Hill West line and trying not to delay through trains on the NEC. Perhaps the most inconvenient part from an operations point of view was NORTH PHILADELPHIA's continued configuration for single direction Rule 251 ABS operation when the NEC on either side of it had long since been upgraded to bi-directional CTC. Trains arriving on wrong-direction tracks would need to take a slow speed indication from a dwarf signal and stay at 15mph through most of the long interlocking.

Eastbound 40L and 42L home signals.

As 2005 approached Amtrak began to make the final push towards eliminating NORTH PHILADELPHIA. The pneumatic point machines were replaced by electrics, new high position light signals appeared on the westbound super-gantry and a brand new eastbound signal gantry was erected.

 

The track layout was predictably simplified with the 31 and 33 switches being removed along with the associated diamond and north side stub tracks. The #25 crossover was also removed limiting westbound parallel Chestnut movements to track #4. On the main ladder all the crossovers were aligned for Medium Speed (30mph) operation and the new signals were able to reflect this.

Finally the trailing crossover on the Chestnut Hill branch itself was removed shifting the division point with SEPTA to the 10-track signal bridge. However the former 50L and 52R signals remained for another decade as automatics.

Former NORTH PHILADELPHIA 50L turned automatic signal 50CH

In the summer of 2005 NORTH PHILADELPHIA tower was closed after 91 years in service with the new Chestnut Hill Branch junction being named LEHIGH after the nearby street. It's single facing point ladder complimenting the trailing point ladder at SHORE interlocking 2.6 miles to the east.

With this context in mind, join me next time as we head into NORTH PHILADELPHIA tower before its closure for a look at the interlocking machine and related equipment.

Caught on Camera: Phantom Indication @ DAVIS?

 Was processing photos from a visit to DAVIS interlocking at Newark, Delaware on Amtrak's NEC and I caught what looked like a phantom or improperly displayed signal indication on the 2N position light signal.  The upper head is displaying Clear in the normal manner, but the lower head appears to have the 12 o'clock (green) lamp lit.  Normally this is used as part of the lower | Medium Clear indications, but today is making up half of an NY Central style double green clear. 

I can't tell if this is a trick of the light or indication of stray current in the signaling hardware. 🤔 Argue in the comments ;-)

Nelson Searchlights Doomed by UP Geneva Sub Re-Signaling

 I can confirm that the Union Pacific Geneva Sub (ex-Chicago Northwestern) re-signaling project that I previously reported on is looking ready to doom the the iconic searchlight complex at Nelson, IL.

 Known for its 4-track CNW main line coaling tower and signal bridges, the Nelson searchlight complex had a chance to escape the 2010's signal replacement ax due to late model age (80's/90's) of the CNW signaling.  While some of the signal bridges are vintage, others are tubular aluminum. 

Unfortunately this is well beyond my territory, but hopefully there is someone local able to perform a through documentation including some video of the searchlight wobble. In an additional bummer, Nelson is likely the best example of CNW oval backed US&S searchlights with at least one 4-track signal bridge entirely comprised of 3 headed signals.