Automatic Signals To Be Axed From NY Penn Station Lines 1 and 2

Amtrak is currently halfway through a project to rehabilitate its East River Tunnels that were damaged during Hurricane Sandy way back in 2012. Lines 1 and 2, the southern pair of tunnels between Manhattan and Queens, were subjected to significant salt water intrusion and although this water was removed in short order, the salt created long term reliability problems. The solution has been a three year project to completely gut the tunnels to the 1910 iron rings and then rebuild them with a new concrete liner and a no ballast trackway. As of now the project is half way complete with Line 2 rebuilt and ready for service.  

Unfortunately Amtrak has also taken the opportunity to remove the automatic block wayside signaling within the tunnel. A total of 13 automatic block signals, some dating all the way back to 1910, were removed from the 2.75 mile long Line 2 tunnel. The 5 eastbound and 6 westbound and 2 westbound repeater signals were replaced by Rule 562 cab signaling without fixed wayside signals.  Rule 280a "C" lamps were added to the 708WA and 704W signals in F interlocking along with a new 580E signal at JO interlocking at the western Line 2 tunnel portal replacing the 1E02 automatic. Similar to CP-MID in the North River tunnels between Penn Station and New Jersey, a new controlled point, CP-LOW, was installed 1000 feet east of the 1st Ave shaft for westbound movements. This creates two Rule 280a "super blocks" within the tunnel in case of cab signal failure. 

Existing ABS configuration for Lines 1 and 2 west 

Existing ABS configuration for Lines 1, 2, 3 and 4 east

In a similar fashion to Grand Central and the defunct Cleveland Union Terminal, Penn Station used a unique style of color light signal as the technology of high intensity, long life electric bubs was still relativity new with semaphores being the then state of the art. ABS signals in the East River tubes were of the "frog eye" variety to create an "offset head" appearance that was customary for automatic signals. The upper "head" had the typical R/Y/G lamps with G/Y on the lower. This allowed for a 4 or 5 block progression for trains approaching the slow speed Penn Station complex, Clear -> Approach Medium -> Approach Slow -> Restricting. As signals at Penn Station can only display slow speed indications at best, the two western ABS locations would best display Approach Medium -> Approach Slow. It is unclear how many cab signal blocks have replaced the 5-6 wayside blocks, but CP-LOW's ability to display Cab Speed (60mph) implies that it matches the high density cab signaling installed on the Jersey approaches. 

"Frog Eye' type NY Penn automatic signal pressed into absolute service.

At this point the adjacent Line 1 will be shut down and reconstructed in a similar fashion over the next 18 months. Fortunately Lines 3 and 4, primarily used by the LIRR, were not damaged in the storm and will be left in their original condition for the foreseeable future. As I mentioned before the North River tunnels were already re-signaled in the late 1990's and will be fully rebuilt after the opening of the new Gateway tunnels in the 2030's.

Decoding Transit Signal Labels

 As I have been covering for some time, North American railroad interlocking stations are generally well labeled. However rail transit is quite a different beast and although some systems have adopted railroad practices, the majority have settles on a pair of labeling schemes that at first may look impenetrable, but are actually pretty straightforward. To avoid burying the lead these schemes are:

• Sequential - Interlockings are numbered, often by line.
• Prefix - The interlockings have names, but a prefix is used for observable signage.
• Milepost - The interlockings may have names, but all signals show a generic milepost.

Of the three systems, sequential and prefix are easiest to decode as it is clear what is the interlocking name and what is a signal designation. Milepost is often unhelpful at identifying the real signal number and the real interlocking designation. Even within these broad bins there is aa bit of variation so here are some examples to help with the lesson.

The WMATA DC Metro is one of the more involved sequential systems. Each line segment is given a letter and interlockings are then numbered sequentially from one end of the line to another with any infill interlockings going on top of that.  Above we see the 08 signal of interlocking 03 on the "G" line at Morgan Blvd. 

The MBTA also uses a sequential system for signal markings and formal documents, although human relatable names also seem to exist. Here we see the 1N signal at interlocking #7, aka Park. Both the DC Metro and MBTA have to ensure that a signal number is not mistaken for an interlocking number so in the case of DC the interlocking has a letter prefix while the MBTA uses a directional letter suffix after the signal number.

MATRA also uses a system with somewhat sequential numbers in addition to a line prefix. These are combined with a 3 digit plus alpha signal ID that consists of a track number followed by some sort of two digit configuration or frog type (seems to be 20, 30 or 40) followed by a signal specific letter.  The signal above would be Line "S" (South), interlocking #225, track #2, type 40, signal G.

The second popular system is to use a letter prefix in front of a signal number. The prefix is usually short for a more human relatable name and can usually be decoded by lay observers.  For example the Pittsburgh Light Rail interlocking on the old PRR Panhandle Bridge station is prefixed by FS.

St. Louis Metrolink uses literally signal number prefixes on the same typographic line. This can cause some confusion for visiting observers when prefix like "S" matches a common direction prefix.

Milepost labeling is the least helpful at providing observers with hints as to the proper way to identify interlockings or other railway locations. In this example from the Denver RTD light rail we can see that interlocking signals have the exact same number plate as automatics. This consists of an S prefix for "Signal" a milepost and a line suffix like PR, CC or SW. The lack of information is somewhat mitigated by the provision of switch identification boards which provide both "lever" number and the switch specific letter suffix for paired turnouts.

The San Jose VTA light rail uses a line prefix letter followed by a milepost-y number and then a modifier like A/B or R (for reverse direction).

There are of course many light rail and transit systems all with their own variations or exceptions, like San Diego still using the L/R system found on US&S CTC consoles, but these examples should get the novice most of the way to decoding transit signal labeling. 

Caught on Camera: Clear to Next Interlocking for UP #4014

For much of the Union Pacific Big Boy 2026 Coast to Coast excursion tour, #4014 was able to operate like any other Class 1 main line locomotive with an ETMS PTC box in the cab allowing the engine to operate in the leading position. However the former Pennsylvania Railroad Main Line between Harrisburg and Rochester, Pennsylvania not only remains cab signal equipped, but was converted to operation without wayside intermediate signals in 2018. Until recently Union Pacific was also a major user of continuous cab signals, however in 2022 they chose to scrap their system due to legacy design considerations that created a lack of synergy with ETMS. While it would have certainly been possible to reactivate the cab signals on #4014 and integrate them with ETMS, the increasingly popular solution to run the movement under Rule 280a, Clear to Next Interlocking, was chosen. I was able to catch this procedure at CP-ROCKVILLE on July 7th, 2026.

Here we can see the westbound track 2 signal at CP-ROCKVILLE displaying Slow Approach, R/R/*Y*, with the "C" lamp illuminated for a stop signal at CP-MARY about 5000 feet to the west on track #1. When the dispatcher lines a route between CP-MARY and CP-BANKS, the signal at CP-ROCKVILLE upgrades to R/Y/R Medium Approach with the "C" lamp lit. The plan for #4014 was to proceed past the far end of CP-MARY and then reverse into Enola Yard to spend the night. Note that the Slow Approach and "C" lamps are flashing with the  same cadence. This indicates that the interlocking has a single source for pulsed lamp current that is then directed to the lamps that require it.

LIRR Greenport PTC - Much Ado About Nothing

We have another data point regarding the FRA's PTC paranoia, this time regarding the Long Island Rail Road's Greenport Branch waiver. Although I missed it at the time, in 2021 LIRR Today published a comprehensive article about the LIRR's efforts to get a PTC waiver for the lightly used Greenport Branch (aka North Fork Branch). Previously one of two regularly served lines to still be operating under a form of the PRR's Manual Block System, in late 2017 the LIRR activated CTC and cab signaling over the entire length of the Montauk Branch, leaving the 46-mile long Greenport Branch as the only US commuter rail service running on "dark" main track territory. What followed next was a lengthy pas de deux between the MTA, which really doesn't want to operate the Greenport service and the FRA, which really doesn't want commuter rail services operating under non-signaled (TWC/DCS/Manual Block, etc) rules.

Until fairly recently non-signaled main track operation could be found on Metro-North, the LIRR and METRA. Although the PTC mandate does not require block signaling and CTC, all three quickly caved in and carried out signaling projects (one might also include South Shore which eliminated its APB territory). The only holdout appears to be the Greenport Branch where, for reasons best explained by The LIRR Today, the MTA is highly reluctant to invest capital resources. No matter, although the ACSES PTC system is intended to work with continuous cab signaling, it does not require functional CSS except for following movements between controlled points.

Let's review how ACESS works.

1. Cab signals codes provide movement authority.
2. Fixed beacons between the rails inform trains of permanent speed restrictions.
3. A data radio system informs trains of temporary speed restrictions and track posessions.
4. The data radio can also provide movement authority when cab signal codes are not present.

With these ingredients you can build a dark territory PTC system. ACSES beacons provide the same civil speed enforcement and the data radio provides movement authority between block limits either using the "Clear To Next Interlocking" functionality or by manipulating track possessions (aka 0mph Temporary Speed Restrictions). Remember ACSES does not replace the LIRR Manual Block Rules, it just stops trains if they exceed their movement authority.

 

This is not the solution that was decided upon. The MTA wanted to install the ACSES track speed beacons and keep sing MBS, after all 4 daily round trips are on par with Amtrak's PTC exempt Valley flyer and Downeaster routes. The FRA wanted temporal separation with 1 passenger train on the entire 46 mile branch. Eventually a compromise was reached with 1 train per MBS block with empty buffer blocks between different passenger trains and passenger trans and freight. To be clear the normal mode of Greenport Branch operation is 1 passenger train on the 46 mile  line, but there are edge cases where this would cause problems.

So why did both parties seem to pass on the opportunity to innovate with the technical capabilities of ACSES? A generous answer could be the chance it would have required software changes on the dispatcher's end to give trains dark territory movement authorities as opposed to the dispatcher setting up and releasing possessions. A more cynical take is that the FRA  wants all regularly scheduled commuter/transit services to be operating under automatic block signaling. The deeper issue is that the FRA considers legacy operating methods as unsafe as opposed to PTC being a nice-to-have overlay on an already safe system. The LIRR has safely operated trains under Manual Block rules for decades, just like Metro North and Metra, but apparently they were all jut lucky that tens or hundreds of passengers weren't horribly killed. 🙄 This catastrophizing is what leads to an inflexibility that cancels service, raises costs and pushes more people onto the highways. 

 

BTW, please check out The LIRR Today blog. It has a major discoverability problem on Google so I want to raise some awareness.  

Amtrak THORN Tower to Close Aug 8, 2026

For over a year I have been tracking the slow motion closure of Amtrak's THORN interlocking tower. located on the old PRR Main Line in Thorndale, PA Opened in 1938 as part of the PRR's electrification project to Harrisburg, THORN was equipped with a state of the art CTC unit lever console controlling  4 remote interlockings in addition to the local 6(!) track full crossover. THORN's extended territory, including FRAZER interlocking which was commissioned in 1994, is what has allowed for the prolonged multi-year closure, which will take place just shy of the tower's 90th year in continuous operation.

Since the first part of THORN's territory, CALN interlocking, was chipped away back in 2020, the local 6-track crossover was rationalized and then turned over to CTEC control while the THORN operator continued to handle SEPTA movements in and out of Frazer yard as well as the daily NS freight entering the line at GLEN. More recently DOWNS interlocking was prepared for complete removal, its signals left standing as the change point between CTEC and THORN's control.  In the final act, kicking off in early 2026, GLEN and FRAZER interlockings were reconstructed with the goal of a Rule 562 cutover once all of the work had been completed. 

THORN interlocking as rationalized in 2023

The closure will bring full bi-directional operation between THORN and PAOLI, with the segment between FRAZER and PAOLI remaining outside the Rule 562 zone for now. The much diminished PAOLI tower is likely next on the list for closure before the heavy lift of installing Rule 562 on the core of the old 4-track "Main Line" begins. One loss that's easy to overlook is the now vestigial limited speed triangle at DOWNS interlocking with those at BRYN MAWR likely the only set remaining outside of Canada.

Another loss will be the intermediate signals at Exton, which were easily accessible from the SEPTA parking lot and well positioned for photography. 

For persons desiring photos of these, the Milepost 29 signals or what's left of DOWNS, you probably have until August 7th assuming transition operations will take place overnight. At 1:30pm on August 8th, THORN's final staffed shift will end. The tower is directly adjacent to the Happy Day's Diner for anyone looking to mark the event. 

Art's LIRR Archives Online...For Now

 Word on the street is that the street is that the person behind Art's LIRR Archives, Art Huneke, has recently passed away. While not quite the #1 source on LIRR tower information, Art's wonderfully Web 1.0 Archive contains a huge amount of primary source material on the evolution of the LIRR in the 19th and early 20th centuries. While the tower and signaling information is scattered throughout the site, it does reward those who take the time to find it. Special attention is given to the older generation of LIRR towers and cabins that were closed in the mid-20th century modernization projects. The page has a wide collection of diagrams and bulletin order scans to track the life and death of these less well known LIRR towers as the rail road evolved into its present form. 

For example Art has extensive coverage of the LIRR's Bay Ridge Branch towers, like NO above, that were opened with the 1928 electrification only to be closed by 1932. In turn we see a photo of the tower that remained open, FN aka FREEMONT, with a Conrail era blue station sign. Other Bay Ridge towers include NU, KN, MJ and of course POND.

At this point there is no word on what will happen to the website so I urge all of you to check it out. Because its all Web 1.0, it is pretty easy to create local copies of the content via the "Save Webpage Complete" function in your browser. Other major signaling content includes:

• B TOWER at Bethpage Jct
• RJ Tower at Rockaway Jct
• R Tower at Richmond Hill
• J/JAY interlocking Construction
• MP/DUNTON Towers 
• WL/LEAD Tower
• BLISS tower
• DB Dutch Kills Draw Cabin 
• PD Tower 
• MV and OLIVET towers
• M Cabin
• D Cabin

Yes, US&S Made Handguns

In the past I have spoken to the importance of looking for the Union Switch and Signal label when purchasing your next M3 switch machine. However, you might also consider looking for the US&S logo when in the market for a M1911A1 .45 caliber handgun. Not only was US&S one of several non-traditional manufacturing concerns drafted into weapons production during World War 2, they were one of the few to affix their corporate trademark to the finished product. Recently Ian at Forgotten Weapons finally got around to covering the US&S M1911 in what might be his only firearm/railfan crossover video

Although they ended up being the second smallest manufacturer of M1911A1 pistols during WW2, this still amounted to over 55,000 units. Anyone familiar with the parts and pieces in a Model 14 interlocking machine can see that making firearms components would be in their wheelhouse. It's unfortunate that Hitatchi has been sidelining the US&S brand after their takeover of the previous parent, Ansaldo.