A blog devoted to explaining the ins and outs of North American railroad signaling, past, present and future. This blog seeks to preserve through photo documentation the great diversity and technical ingenuity of 20th century signaling and interlocking hardware and technology. Related topics cover interlocking towers and railroad communications infrastructure.
Note, due to a web hosting failure some of the photos and links may be unavailable.
I have received reports that the former LIRR POND tower has suffered a fire related incident. The extent of the damage is currently unknown, but the wooden structure would be highly vulnerable to flame. POND is located on the LIRR Montauk Branch at the west end of Fresh Pond Yard, which now serves as the base of operations for the New York and Atlantic and, by extension, rail freight for the entirety of Long and Royal islands.
Built in 1905, POND was on the LIRR end of the junction with the New Haven / New York Connecting RR's freight extension to Bay Ridge via the Hell Gate Bridge. Closed as an active interlocking station at some point in the 70's or 80's, POND outlasted its newer and more robust sibling FREEMONT tower on the Bay Ridge Branch by being repurposed as the NY&A's freight/yard office. It's location in an isolated and wooded area probably meant that transient related vandalism was inevetable. Hopefully the damage is such that repair, rather than demolition will be warranted, but I am not optimistic.
About a decade ago a superb signaling related blog run by a retired US&S signal engineer came to my attention.Titled The Has Been, the site was self-hosted and used dynamic IP address services making it almost completely invisible to the wide world of Google searching. Unfortunately, after a few months it made a switch to a new dynamic DNS service and because I was not in "the loop" the site effectivly went poof.
Well thanks to some new friends I have been made aware that the site still exists, obtained a stable DNS entry and has been updating regularly over the past decade. The site is still not searchable on any public search service and has several other internal features to prevent automated scraping. However it does contain a keyword search and an archive that is served up by calendar month. I figure I am going to have my hands full catching up on all of the great signaling content I have missed. Anyway the current URL is thehasbeen.org:9090, enjoy!
In a huge surprise it seems that Fort Worth's iconic TOWER 55 is under threat of immediate demolition with work to begin on Monday, November 14th. A report went out on Twitter, but the planned date was pushed back.
The iconic railroad interlocking Tower 55 in Ft. Worth is being demolished today noooooooo ðŸ˜
As we have seen with demolition efforts with AR and MG towers near Altoona there are numerous factors that could yet scuttle the demolition plans, including detection of hazardous substances like lead or asbestos. It is also unknown if the tower will need to be gutted first or simply demolished as-is.
TOWER 55 is located in downtown Fort Worth and consists of a3x2 diamond crossing between two major Union Pacific main line with connecting tracks on all four quadrants. The junction is so complex that it has its own signal committee posting handy "you are here" signs. It is on the order of such towers as SANTA FE JCT in Kansas City or F TOWER in Fostoria.
The tower checks none of the boxes of demolition risk. It's made of brick, in very good condition with modern windows on the operator's level. It is located in a quadrant of the jct behind a fence line and is used by local MoW or C&S crews. The most likely explanations are some sort of spite (aka "cost cutting") or a need to expand the east-west line from 2 tracks to 3, which could require running the new track through the tower's footprint. If anyone knows anything more specific or has updates about TOWER 55 please leave them in the comments.
It has been confirmed that Amtrak has relocated the train director(s) working K TOWER at Washington Union Terminal from the historic 1908 structure and into a small office in the Railway Express building adjacent to Track 29 on Union Station's lower level.
Unlike R Tower in Sunnyside yard, where a similar relocation immediately preceded demolition to make way for an Acela maintenance facility, the historical significance of Washington's K TOWER is well understood. In 2017 I reported on plans to cover over the entire union station approach with some mixed use development with K Tower specifically singled out for conversion into some sort of high end bar. The culprit here is some combination of Amtrak's desire to simplify "management" and also cut costs along with some technical upgrades that were evidently completed behind the scenes.
As constructed in 1908, Washington Terminal was controlled by at least three US&S Electro-Pneumatic equipped towers, A Cabin, C Tower and K Tower. In the 1970's, K Tower had its long Electro-Pneumatic machine replaced with a then cutting edge N-X type interface and model board that drastically cut the need for staffing (and floor space) and centralized control of the entire terminal into a single location. This change likely took place around 1975 as the construction of the DC Metro's Red Line required the demolition of C Tower. Although cutting edge for the 1970's, by the 2010's the N-X machine was becoming increasingly difficult to maintain as parts were long out of production and failures could become rather nail biting in terms of getting the machine working again.
Although decorated with some LCD screens, the big old N-X panel's days were numbered and as soon as the control was converted into a video display interface, the human train director was no longer limited to being in the tower itself, especially if CCTV feeds could be provided. Although I suspect the historic K TOWER will be maintained and serve a railroad function, while active as a work site the HVAC, restrooms, etc would all need to be maintained to a higher standard. Plus there is the added benefit of management being able to "pop in" to "supervise". It is quite possible that the N-X panel was actually replaced years ago and COVID simply delayed the inevitable. K Tower would therefore be a rather extreme example of a "return to the office" policy. Still, given that computers can be installed anywhere, there is always the chance that the K TOWER staff could find themselves back in the old tower in the future, baring some redevelopment effort.
K TOWER joins the fate of many other pre-video "panel" type interlocking setups that I discussed previously in the content of Hoboken's rather short lived TERMINAL TOWER. Given the ease at which an N-X panel can be converted to a video interface, it is entirely possible that, rapid transit systems not withstanding, we might see electro-mechanical machines outlast hard wired N-X panels in staffed towers.
More details are emerging about the fate of the Power Director's Office in Baltimore Penn Station. The entire 1911 station building is undergoing a major restoration with the upper floors slated to be turned into office space. Unfortunately the Power Director's Office, located in room 222, is included in the redevelopment plan and will be cleared of all the PRR era 25hz railroad electrification control equipment that has remained in place since the office was closed in the mid-1980's when CTEC took over.
The less bad news is that some portion of the equipment including at least the large display board, will be relocated to a more public part of the station. A local TV newscast got a tour of the office and according to their report this new location appears to be in the 1911 building where the current ticket and baggage rooms are now. (Those facilities will be moving to a new station building across the tracks). It is unclear if all of the equipment, including 1940's based telecom gear for the SCADA functionality, will be moved or just the visually interesting conversation pieces. Also being lost is the physical character/ergonomics of the current Room 222 space and any support infrastructure like cable ducts and light fixtures.
As I previously reported, Amtrak recently leased the former Harrisburg power office to the Harrisburg Chapter NRHS for preservation and it currently shares the second floor of Harrisburg's Penn Station with a number of third party offices. Other shuttered offices still exist at 30th St station and the New York Penn Station support building.
I've mentioned this phenomena before, but in this day and age when a Class 1 appears to have "forgotten" about some bit of classic signaling its usually because they intend to sell the line or they are planning something much more drastic than a re-signaling project. Usually this is complete signal removal (I'm looking at you Buffalo Line), but in the case of the largely PRR signaled NS Fort Wayne Line west of Alliance, NS apparently had in mind a radical single tracking project.
Currently the Fort Wayne Line is double track from the Cleveland Line split at CP-ALLIANCE (MP 82) to CP-MACE (MP 110), CP-ORR (MP 124) to CP-BIG RUN (MP 138) and CP-MOHICAN (Mp 157) to Crestline (MP 188). The line has always been a step child after lost traffic was diverted up the Cleveland Line to the Chicago Line. I would not be surprised if the line had managed to stay PTC exempt due to light traffic. The current Conrail era CTC signaling dates from the late-1980's and matches that installed on the former PRR Middle Division.
In 2022 NS released the following single tracking plan that would result in the likely retirement of all remaining PRR position lights on the route and also bring the curtain down on the last major instance of PRR signaling on NS.
Retirement of selected double main line track operations into single signaled bi-directional track (Rule 261).
Approximant limits of project will be PC 84.8 to PC 188.3 on the Fort Wayne line of the Pittsburgh division.
Retire one main track at mile posts PC 84.8-96.7, 157.3-160.1, 161.9-169.4, 178.0-188.3. Change method of operation at mile post limits of 160.1-161.9, 175.1-178.0 to Non Controlled Track.
The good news is that as of 2022 no movement has been made on activating this plan and the recent manpower and capacity problems might cause some change of heart. Regardless, get out to Ohio and get your photos ASAP.
In the realm of railroad interlocking machines, what does this...
Have in common with this...
Well they are kind of the same thing, the latter just being an improved version of the former that does away with most of the sweat and tears. Just like dinosaurs evolving into birds, 19th century mechanical interlocking systems evolved into smaller and lighter form factors with more and more automation until the technology reached its ultimate dead end. It might seem that a Union Switch and Signal electro-pneumatic power frame is a completely different piece of kit than the "armstrong" monsters that came before, but if we lift the hood we can see how the past influenced the future.
Setting aside who invented what and when, by the end of the 19th century there were two common mechanical interlocking styles coming out of the UK. The Style "A" Machine used a vertically oriented interlocking grid where lever bars on the Y-axis would interact with locking bars on the X-axis via a system of tappets. This style is what tends up show up in books and diagrams as it is the easiest to visually digest. The other system was the Improved Saxby and Farmer Interlocking, this used a horizontally oriented locking grid with lever bars moving in the x-axis interacting with locking bars in the z-axis via dogs. Regardless of the terminology, the key takeaway here is that there were two primary interlocking systems and Union Switch and Signal wound up with the US license for the Improved Saxby and Farmer variety.
Above is an IS&F implementation at the abandoned Buffalo, Rochester and Pittsburgh Railway tower at C&M Jct near Du Bois, PA. We can see how the lever bars are engaged by rotating shafts. The shafts were in turn attached to cranks that were in turn engaged by rockers that changed the back and forth motion of the large interlocking lever into an up and down motion that then rotated the shaft, ultimately sliding the interlocking bar back and forth in the x-axis (if the interlocking conditions allowed). In the photo below we can see how the rockers engage with the cranks behind the row of levers on an more complete lever frame.
So what does this have to do with a Model 14 machine? Well if we literally lift the hood we immediately find the exact same style of longitudinal lever bars, just slightly smaller and more compact.
Because on "power" interlocking machines tower operators no longer needed large physical levers to throw the switch points via a long length of pipe, all the complex mechanisms needed to convert the back and forth lever motion into longitudinal motion can be replaced by a miniature rotating crank.
In case you were not yet convinced, the shafts that used to move the lever bars in the x-axis are still around to engage with the locking magnets controlled by the relay logic elsewhere in the tower.
In contrast, the other major type of North American pattern power interlocking machine, the GRS/Taylor "Pistol Grip" type, used the vertically oriented type of locking grid.
This horizontal vs vertical orientation explains why the largest Style "A" type frames were often in tall/narrow buildings, like STATELINE while the largest IS&F frames were in squat buildings such as DOLTON JCT.
STATELINE Tower Outside
STATELINE Tower Inside
DOLTON JCT Tower Outsde
DOLTON JCT Tower Inside
The US&S "Model 14" type interlocking machine was not even the final iteration of the Improved Saxby and Farmer type interlocking! That distinction belongs to the Westinghouse Brake and Saxby Signals Style V machine developed for the London Underground in the 1950's and used as late as 1967 for the all new London Victoria Line. The Style V was a Model 14 style locking bed turned on a vertical orientation with the levers being remotely actuated, typically using compressed air, allowing the interlocking to be remote controlled. I will probably give Style V's their own post at some point, but I wanted to give them a little shout-out in this context. Here we can see a Style V in action a bit after 1:31:25 in a 1960's Victoria Line construction public information film.
In its time railroad signaling was at the vanguard of high tech right along with the telephone system. With the pace of technology today, it is hard to believe that the concept of IS&F mechanical interlocking would be in use from before electric traction was invented up through the ATO equipped Victoria line. I guess it will sort of be how flavors of Z80 microprocessor will be in mainstream use, decades into the future.
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