The Mystery of the Zombie Route

This came up as I was recently out along the New Englande Central near Bellows Falls, VT when I noticed something strange at the north end of the Walpole siding.

The southbound searchlight mast was displaying an Approach Medium and my first assumption was that the signal at the Bellows Falls diamond crossing was still at Stop and due to the short distance between the south end of the siding and said diamond crossing, the signal at the south end of the siding would be displaying Approach. This is a pretty common technique to deal with a short block without using a flashing Advance Approach indication.

Well, you can imagine my surprise when I traveled back to the south end of the siding to discover a Medium Clear indication for the normal route over the single trailing point switch. The signal for the Bellows Falls diamond, about 1500 feet to the south, was also displaying clear. So, what is going on here?  My first thought was that this was some kind of zombie route. The New Englande Central flipped the orientation of the turnout to create a zombie route, but didn't have the wherewithal to alter the signaling. These sorts of double track passing points where trains enter a short stretch of double track ABS on a normal route and exit on a diverging route, were that uncommon in the early CTC era. The north end of the siding even looked a little suspicious with a bracket-dwarf arrangement that could have once been a normal mast and center mounted dwarf.

The other hypothesis is that this is due to speed control over the Bellows Falls bridge. Using signaling to encourage speed control, typically involving slow speed signals, wasn't unheard of in the pre-PTC world. Although Approach Medium to a Medium Clear over a straight route is quite out of the ordinary, The train approaching the interlocking will be traveling at medium speed per rule with the Medium Clear further acting as a reminder. After the 2016 Amtrak Frankford Jct derailment the FRA leaned heavily on various passenger railroads to use signals less favorable than Clear to help prevent accidents at significant speed restrictions. Since the Bellows Falls Bridge is 10mph compared with 50-60mph approach speeds, this seems like  the sort of remedy the FRA would require on a PTC exempt rail line.

So which is the more likely scenario? Well, the answer would come from YouTube of all places. If you remember back to that interlocked diamond crossing at the Bellows Falls passenger station, the northbound signal is at the end of the platform and likely visible in rider's videos. A Clear signal on the northbound mast would imply the zombie route, while something other than clear would imply speed control. Well after some searching I found an answer.



So the northbound mast is displaying Approach Medium, which I said implies speed control, however the date of the video is the most important clue. 2013 was well before the FRA freakout over speed restrictions implying that the South End Walpole was displaying a Medium Clear over a normal route in the northbound direction as well. The situation is still not 100% clear cut and there could be alternate explanations that don't involve a passing point type layout, for example the siding being changed from the west to east side of the main line. Still, its a unique situation that lead me down a rabbit hole. It will be interesting to see what if any changes the re-signaling project brings.

Spooky Signaling - Zombies and Phantoms

As the smell of pumpkin space fills the coffee shoppes and the foliage begins to change colors, I figured I'd do a little Halloween themed post about zombie and phantom signals. While I may have touched on this topic as part of other posts, apparently I never gave zombies and phantoms a dedicated post so here you go.  Zombie signals are signals that exist, but govern a track that does not and phantom signals exist within the interlocking logic, but not in real life. Both appear where interlockings are having bits and pieces removed with zombies being out in the field and phantoms on the interlocking machine or other user interface. However in both cases the signal must still wired into active signaling infrastructure so a signal standing aside a completely removed rail line is not a zombie and a signal lever painted white as a spare is not a phantom. 

2W zombie mast at CP-LEHIGHTON

The best example of a zombie signal was the 2W small target searchlight mast at CP-LEHIGHTON on the former Conrail Lehigh Line. Located at the point where a connection to the old CNJ Main Line was plugged into the old Lehigh Valley Main Line, CP-LEHIGHTON came about when the staffed tower was closed and Conrail created a single main line from the best parts of each predecessor roads. Governing a stub industrial track on the route of the old LVRR main, industry closures eventually made the industrial track surplus to requirements between 1992 and 1997.  However Conrail faced non-trivial costs to alter the interlocking, especially since the signal had bulb out protection. Their solution was to leave the signal in place with the searchlight bulbs in a low power mode.

Remains of 76LA after the signal was finally removed.

Another good example is the 76LA dwarf signal at DOWNS interlocking on the PRR Main Line.  Again, this governed an industrial track that was eventually removed from service, but once again it was cheaper to leave the signal in place.

Zombie CPL at LAUGHLIN JCT in 2009

I recall reading that the eastbound signal for passenger traffic to Pittsburgh's B&O Station at LAUGHLIN JCT became a zombie after the rail service was discontinued. While the mast was still there in 2009, a partial re-signaling in 2003 may have finally extinguished the lamps. 

Does the 10RB signal from nowhere count?

Now one minor distinction are signals where the tracks have been cut just past the insulated joint and signals that are just floating out in the middle of nowhere.  PAOLI tower's Hill Track 10RB signal went on this journey first standing next to the end of track and later standing next to nothing. While standing next to cut track isn't quite as "zombie" as standing next to nothing, I'm not going to nitpick. 

Track 2 signal is still lit over an empty roadbed.

Another interesting zombie signal situation was on the removed #2 track on the same PRR Main Line between CALN interlocking and PARK tower. This track was removed around 2010 and featured 3 zombie intermediate signal locations for the better part of a decade. In this case in addition to having to modify the old 504 CTC system controlled by THORN tower, Amtrak also was able to put off having to do the regulatory process of discontinuing that track's signal system, even if the track did not physically exist. 

Sidings exit signals are another common source of zombie signaling as industrial closures can lead to siding removal by MoW forces while the related signaling is left in place until the signal department decides to deal with it.

MIDLAND interlocking in Gainesville featured a zombie derail.

The final type of zombie signal I should mention is removed diamond crossings. These are expensive to maintain and while often the diamond is removed with the tracks and signals on either side remaining, its not unheard of for the entire crossing line to be torn up except for the signals which may be the property/responsibility of the surviving route. I can't currently find my example of a zombie diamond signal, so I posted a zombie derail instead. 

Examples of phantom signals are a bit harder to document and were largely the product of mechanical interlocking where changes in the physical plant would require extensive physical modifications to the physically implemented interlocking logic.  In certain locations it made more sense to leave the unused levers in place where the operator would still have to line them as if they were still in the field. While I am aware of phantoms also existing in relay based interlocking plants, the only example I can currently come up with is the late great ALTO tower in Altoona, PA. When the layout was modified in the 1980's, several signals in the east end of the plant were converted into phantoms, specifically the 20L, 34R and 38R, as they crossovers they had protected had been removed. On the model board the signals existed (labeled phantom), but it would not be possible to hold a train at one. 

In summary, far from being scary, zombie and phantom signals are a neat little quirk that occurs at the intersection of abstract logic and the real world.

CSX Demolishes New Hampshire's Penultimate Tower

The effects of CSX's takeover of the Guilford Rail System is already becoming apparent as I have discovered that New Hampshire's second to last surviving interlocking tower, MA in Manchester, has been demolished. Never a big state for main line railroading, New Hampshire did have some fairly robust Boston and Maine infrastructure in the Merrimack River Valley between Nashua and Concord. The B&M had a thing for placing towers at the end of yards and had such towers in the cities of Manchester and Concord.  Both towers were low level brick and concrete "cabin" types built around 1944 to the same plan and designed around a unit lever (CTC style) console and associated local relays.

B&M MA(nchester) Tower, just visible behind the tree line at center left.

CSX's chosen victim was MA tower in Manchester, which is especially vexing because as you can see in the photo above, I had been a stone's throw away taking photos of the deactivated remains of CPN-28 in October, 2022, only becoming aware of the tower's existence after I got home. I had plans to re-visit the area, but had not been able to put them into effect by the time the tower was demolished in May of 2024. Luckily a local urban explorer visited the tower in February, 2024. According to a history published by the Boston and Maine Historical Society, the tower first gained CTC control of the entire New Hampshire Route Main Line in the 1950's before closing entirely in 1974.



In a bit of good news, the tower in Concord had been identified some years ago by local preservationists who are currently involved in its restoration. The story behind the preservation effort is told in the video below. Unless something has been overlooked it is believed to be New Hampshire's last standing purpose built interlocking tower.

Once again the lesson is to be aware of your surroundings and do the research before you go on an expedition.  This was not even the first time I missed something in Manchester as in the fall of 2020 I had failed to get photos of CPN-28 before it was taken out of service despite performing a historic walking tour just a half mile away. 

Decision 2024 for the Signaling Single Issue Voter

Just like in 2020 I thought I'd provide some political analysis for the single issue railroad signaling single issue voter. Not sure who that would be exactly, but in a country this big it has to be somebody. In 2020 the big political signaling issue was PTC and the Trump administration's general failure to soften the regulations or roll it back before PTC driven signal replacement projects ruined the legacy infrastructure. In 2024 PTC is still proving to be a problem in terms of ETMS outages cancelling passenger services, but I don't see either party lifting a finger to solve the problem and almost all the vintage signaling is gone anyway.

In terms of regulation in general fears that the East Palestine derailment would trigger a moral panic on the order of the 2008 Chatsworth crash proved to be unfounded and I have to give the Biden administration real credit for taking a political risk and not rushing through knee jerk regulations that would damage the rail industry. We might see a minimum distance between hotbox detectors well below the old 20 mile AAR standard, but several railroads like the Southern and N&W have been on shorter intervals for decades.

Of course one area where I would call regulations too weak was the FRA's decision to allow CSX to remove the cab signal system on the RF&P. Coded track circuits are still more reliable and secure than over the air data links running off internet connected servers and attempts to use ETMS as safety critical cab signaling is going to cause a bad day. Another regulatory issue that is also in also in the blind spot of both parties is the FRA's use of shadow regulations to throttle the deployment of higher (80+ mph) speed passenger rail service. This might find a sympathetic ear on the current supreme court, but since it doesn't affect Class 1 freight RR's industry is uninterested in mounting a challenge and passenger operators known they are beholden to public funding.

A major factor in favor current Democratic politics the focus on anti-trust and industrial consolidation. Today the biggest threat to interesting signaling is industry consolidation, as seen with CSX's snapping up Guilford and CP buying KCS. I would expect proposed east-west RR mergers, like BNCSFX or UPNS, not passing regulatory muster under a Harris administration. In terms of trade policy, the vast majority of signaling equipment is still produced domestically so tariffs aren't necessary to fight off some invasion of cheap Chinese signaling hardware because that threat simply doesn't exist.

Finally, because legacy signaling has been so thoroughly decimated, the only way forward is new rail projects, which is one of Biden's signature issues. While a lot of the projects that have been built have employed locally prevailing signal rules and styles, there is always the chance of a Caltrain style speed signaling conversion or expansion of the Northeast cab signal network. 

Therefore if you are looking for my opinion I would endorse the Democratic ticket primarily for blocking additional rail mergers and funding the construction of new signaled passenger routes. They have earned my trust on avoiding bad regulation and are no worse than the alternative in cleaning up the FRA's existing over-regulation.

Portland MAX Signaling Primer

In the 1980's and 90's North America's light rail renaissance didn't just save money over traditional urban metro systems by embracing street running and low level boarding. At the time, the signaling standard for "heavy" metros involved full CTC and cab signaled ATC, which came with both high infrastructural and operational costs. However light rail systems got a pass to re-write the rule book and adopt signaling practices that hankered back to the low cost interurbans of old with single direction operation and limited use of interlockings. While I have previously covered two examples of these low cost signaling practices in Denver and Dallas, I recently had the chance to explore a third in Portland Oregon.

Beginning operations in 1988 and seeing significant expansion in the 90's and 2000's, Portland's MAX light rail has the typical mix of downtown street running and dedicated suburban rights of way with operating speeds up to 55mph. The signaling of choice is single direction 3-aspect Automatic Block signaling using US&S transit type signal heads. There is little formal distinction between interlocking and intermediate signals each signal is the same in having a line-prefixed number plate.

One quirk of the system is the setup of having an ABS exit signal at each station and another ABS signal between stations. When a station platform s within a block, the signal will at best display yellow Approach so there is a distinct rhythm of exiting a platform on a Clear then entering the next on Approach. Intermediate signals on the main line away from stations are often of the high mast variety with earlier installations using US&S N type mono-block heads.

A key feature of the MAX train control system is the use of fixed inductive Automatic Train Stop (ATS). Unlike some other systems, MAX actually includes a bit of overlap to get trains stopped before they hit something. This is made possible by an LRV's enhanced braking performance necessary to handle the challenges of street running. Apparently MAX also has a few ATS based speed control timers that function independently of fixed signals, but are indicated by wayside signs.

Interlockings are limited to major junctions, yards and a few select crossovers. These are supplemented by hand operated temporary block stations. As I said before, both ABS and Interlocking signals are largely the same except for the possibility for route indications on the interlocking signals. This can range from the use of a single lamp in the "call-on" position, or separate heads, each governing a specific route. The wayside signals are supplemented by switch position indicators of the US&S ES-20 variety.

When Urbex Meets Signaling

While there is a lot of crossover between the urban exploration (Urbex) community and the rail enthusiast community, the Ven diagram doesn't quite work the way you think it does as there is both the type of enthusiasm the individual is involves with (rail, urbex or both) and the type of things they explore.  When railfans explore rail stuff, they tend to put the resulting content in the rail bin, even if they are also into Urbex.  Qualified railfans know the jargon and historical details to properly label their content, rendering it searchable and discoverable. On the other hand, Urbex people who aren't railfans, can get into a lot of interesting rail places, yet have little idea of what they are looking at, therefore harming discovery.

Not so long ago I found some critical WINSLOW tower interior photos from 2003 on an urbex blog site that just hadn't happened to appear on casual google searches until recently. In the same vein, I also found a great exploration of the former PRR MG tower on the famous East Slope between the Horseshoe Curve and the summit at Gallitzin. I routinely search for new "interlocking tower" videos, but not "switch tower" because the genericness of the term returns a lot of bad results.  It was only after several years would YouTube searches include this video in my interlocking tower search due to the key words in the comments.

Despite their lack of historical context, the Urbex community can assist the railfan community by being willing to generally take more risks than railfans. In this example MG tower is known to see increased police patrols to the point where the risk of visiting is well known.  On the other hand, Urbex folk don't care about getting train photos and can put more effort into not being see in addition to just having more experience in not being seen. Therefore, while railfans steered clear of MG, this guy was able to made a comprehensive video documentation. Another popular urbex assist has been the Hoosac Tunnel in northwestern Massachusetts, which sees both explorers and ghost-hunters occasionally getting some footage of the searchlight signals inside.   

Anyway, the next time you are looking for some open source intelligence on some hard to access signaling artifact, try to use some urbex search terms. You might find something surprising.

New Signals at Portland Union Station

For the last year or more, Portland (Oregon) Union Station has been involved in a slow motion re-signaling project that will unfortunately zap the last active vestiges of VC Tower, which closed in 1996 as Oregon's last active interlocking station. 

Until labor dynamic forced a change in the early 2000's it was not uncommon for railroads to splice old interlocking hardware, like switches and signals, into new control logic. VC was one such example where the eastbound signals were left untouched. 

These included a short mast signal off of passenger track #1 with a mix of GRS type E and L&W modular lamps, a modernized GRS type MF triangular dwarf, (popular with UP in the 80's and 90's) off main track #4 and two vintage GRS type MD dwarfs on track #3 and #5 that likely date back to whenever VC tower changed over from semaphore signals. 

The replacement will be an obtrusive double cantilever mast for tracks 3, 4 and 5 and a likely modern type mast on track #1. 

The current two lamp dwarf signals appear to consist of a red lamp over a yellow lamp, which would provide for Y Approach, R/Y Diverging Approach and *R* Restricting, although was not able to observe actual operations. The new signals seem to bring Y/Y Approach Diverging to the table. 

The changes aren't limited to the east side of the terminal. For some time passenger tracks 1 through 4 have been un-signaled with the west end of of those tracks being reached via non-interlocked M23 powered switches. Based on bagged station track signals and a bagged through track mast it appears the west end will also be interlocked, including the presently hand throw station track #1.

This will hopefully cut a couple of minutes off the run time, with trains possibly able to make hotter stops, instead of creeping down the super long platforms.