Guilford Country Resignaling Updates

With the re-signaling of the former Guilford Rail System/Boston & Maine Western Route Main Line accelerating rapidly, I managed to carry out a multi-day road trip to gauge the situation and take what photos I could. With the re-signaling already complete between the Mass border an the Exeter, NH area I started at Dover, NH and worked my way north to Saco, ME.

My first discovery was that CSX was doing more than just swapping out the signaling and the signal rules. Outside of the MBTA zone the interlockings have all been renamed from the Guilford era CPF-Milepost format to location based names, some of which call back to B&M telegraph cores and others more modern things like road names. Overall this marks an improvement as the CPF names were a result of the crazy Guilford owner kitbashing a 715 mile long main line between Mattawamkeag, ME and Sunbury, PA in 1981. Changing the interlocking names was actually in support of moving away from the Guilford's "Freight Main Line" 0 to 715 mileposts. Unfortunately CSX did not restore the original B&M mileposts from Boston and instead established an MP 0 in Portland Maine that increases as one travels west. Although the chaining was not changed, stone "Boston" mileposts defaced with spray paint instead of reused.

Main track Clear at CPF-243

New signal bridge at Rollingsford Jct

In the Dover area the B&M signaling, including classic signal gantries, is very much on its way out. The holdout signals at CPF-244 in downtown Dover are also going to be removed without replacement due to the reduced need for switching movements that need to occupy the main line. Dover actually represents a bit of a B&M signaling island right now as just over the Main border, double tracking improvements have already ushered in Seaboard signaling all the way through Wells, ME.

Part of these improvements include a new full crossover designated WILLIE west of the Wells, ME Downeaster station. The only details of note is that standard CSX switch procurement is now from Apex and the color light signal modules are now from Progress Rail instead of Safetran.

Milepost 211 searchlight automatic. Note the new CSX milepost number.

The section between Wells and Saco was re-signaled by Guilford in the 1990's with brand new SA searchlights, however new signal mast footings are in place at all of the locations as CSX can't let us have nice things.  CSX has also replaced all of the former Guilford defect detectors with brand new units, which runs counter to their practice after the Conrail merger where CR readouts lingered for over a decade.

Turned signal mast at Saco.

At Saco a turned target type signal awaits an unknown fate. The sale to CSX caught some of the Guilford's own re-signaling projects in mid-stride. If any Federal funds were used as part of Downeaster service improvements, it might be difficult for CSX to scrap this work so we will have to see what they choose to do. 

CPF-LO w/b dwarfs

The corridor between Lowell and Ayer has seen no recent activity on the part of CSX. This might be due to the state of Mass owning all of part of the infrastructure or just the lack of passenger operations bumping down the priority. I am pretty sure the state owns the Northern Route Main Line to the wye junction north of town and possibly to the New Hampshire border and plans for Nashua commuter rail will likely dissuade CSX from making changes the government might ultimately pay for. While I already reported on the re-signaling of Lowell's BY interlocking by MBTA, CPF-LO west of the station is intact, although all connections to MBTA tracks have been cut. 

CPF-307 eb-B&M signal bridge

CPF-307 new w/b searchlight mast.

The ABS signals and CTC siding on the Guilford track between Lowell and Ayer are also intact with each end of the siding featuring an intact B&M signal bridge. CPF-307 even has what appears to be a fairly new 3-head searchlight mast, although it is unclear if this was carried out under CSX or Guilford.

CSX Finds a New Old Off Brand M23

I few years ago I posted an article covering changes to the US&S logo over time as seen on its M3/M23 line of electric point machines. This article also covered off brand copies of the M3 from companies such as Patco Rail Services and Vossloh. CSX in particular had gone all in on the Vossloh "VSM-24" product.

Well it appears that CSX has found a new supplier, kinda.  Apex Rail Automation appears to have taken over Vossloh's VSM-24 production line as the only thing that has changes is the stenciling and the lack of a cast company name on the circuit controller housing.

Of course the other news headline is that CSX is replacing its B&O era GRS Model 5F and 5H machines in B&O territory.  Maybe Vossloh made CSX a offer they couldn't refuse and then realized they then couldn't make a profit. We'll see if Apex has any better luck.

NS Ashville Cantilever is Kaput

I have seen photos of the great Southern RR cantilever signal in downtown Ashville, NC being cut down for scrap. With modern style ABS signals in the flood affected area now turned out of service it appears that Hurricane Helene has done what NS failed to do with a previous FRA petition failed to do and end the heritage signaling on at least part of the former Southern S-Line. 

Let's be clear, the only reason the S-Line still had much of its former Southern RR signaling was because declines in coal traffic had ended through trains on the line and NS was trying to actively discontinue the signaling system. Much of the line was still operating under Rule 271 (aka TWC/ABS) with a lot of the signaling dating from around 1980 in the late Southern era with generally more modern signal structures, but split ABS masts following the right-hand-rule.

Although NS appears to be scrapping the Southern-era signals on the hurricane damaged portions of the line around Ashville and into Tennessee, it is unclear if the FRA will re-visit the abandonment or if some sort of bog standard NS Rule 261 setup will replace it.  Also, the parts of the line not damaged by flooding will probably remain unchanged as the State of NC is making noise about passenger service on the route which will come with Federal $ for a resignaling project.

Harrisburg Power Office Is Now Mostly Up and Running

When we last checked in on the Harrisburg Power Director's office about a year ago in 2024, the Big Board had been fully illuminated and most of the Westinghouse "Visicode" SCADA equipment had been reactivated with the help of modern technology simulating the presence of the field equipment like substations and such. However, because the 1930's PRR electrification projects had been funded with depression era WPA loans, the PRR had to spread the wealth and about half the office used GE "Code Selector" hardware that was more complex in operation and not as well documented. 

Well between March and September 2024, members of the Harrisburg Chapter NRHS managed to locate the documentation for the GE gear (it was sitting on a storage shelf) and were then able to restore most of the GE panels to operation, which is especially useful that represents the bulk of what was still operational on the old PRR Main Line up through 2013. The GE gear brings the added fun of step switches being used to store digits instead of all-relay registers for the Westinghouse part of the office.

As if step-switches weren't enough, between September 2024 and March 2025, the team also reconnected the alarm lamps and bell which further adds to the effect.

Still to be addressed are the metering circuits along with programmed simulation elements that would allow visitors to participate in directing flows of 25hz power to virtual train movements. Still, the Harrisburg power office  is mostly complete in terms of being "a thing that functions as it once did" so watch out for planned opening dates as the chapter is still trying to figure out how to manage regular hours.

Caught on Camera: Double Green Clear

 With the CSX takeover of the former Guilford Rail System empire, there's a real risk that we might see the end of double green clear signal indications in the wild. Most commonly associated with the New York Central, double green clear is an artifact of two position ABS semaphore signals with an upper head of R+G and a lower head of Y+G resulting in the combination of R/Y for Stop and Proceed, G/Y for Approach and G/G for clear. A part of the NORAC set of signal indications, its last common use was in New Englande on the former Boston and Main territory operated by the Guilford Rail System and the MBTA.

As previously covered, while Guilford wasn't perfect it did maintain a bunch of legacy signaling practices, like bracket masts, up into the 21st century. Even in places where new signals were being installed, two head "distant" signals to interlockings would still display G/G as opposed to G/R. In fact you can see it for yourself on Google Street view on the milepost 2xx intermediate signal adjacent to the Main St grade crossing in downtown Saco, Maine. 

Lit for an approaching train we see double green clear displayed on a thoroughly modern target type LED mast signal. In fact I saw this street view while scouting Guilford automatic signal locations on Google Maps and was not only able to locate the normally dark (approach lit) signal, but catch it displaying the coveted indication for a northbound Downeaster train. 

Unfortunately it appears that this location will be replaced by CSX within the year with no chance of it retaining the double green clear. However with 5 round trips a day, its pretty easy for anyone in the area to  catch it for themselves. 

It's Electric! - The Westinghouse Brake and Signal Style L Frame

Every so often I mention the Westinghouse Brake and Saxby Signal Company which was the result of the British Commonwealth's Westinghouse Brake Company purchasing the then dominant UK railway signaling supplier Saxby and Farmer in 1901. For those of you who are unaware, George Westinghouse's claim to fame was the invention of the automatic railroad air brake and he set up corporate entities in both the US and overseas to market his produce. In an early example of corporate synergy, Westinghouse also became involved with railway signaling, either directly producing signaling hardware or owning a signaling subsidiary in many markets. Because there is little sense in reinventing the wheel, the Westinghouse corporate empire would cross-license signaling technology between its various arms. This is how US&S became the supplier of the Improved Saxby and Farmer type mechanical lever frame in the United States and how WB&SS Co would come to sell a power interlocking machine awfully similar to what would become the Model 14 family sold by US&S.

Balham Signalbox Style L Power Frame

As railway signaling moved from purely mechanical to incorporate automatic blocks, electric signals and power operated point machines, interlocking machines effectively became hybrids with both mechanical and electric locking. 19th century mechanical methods would continue to provide the route locking, while magnets and solenoids would lock the levers electrically based on track or switch position circuits. 

Electric locks on a traditional "armstrong" type lever frame.

Since safety critical railway signaling relays were quite expensive, signaling suppliers had an incentive to carry out as much logic as possible in the mechanical layer. Therefore even "power" interlocking machines like the GRS pistol grip style or US&S crank lever style still made use of miniaturized mechanical locking grids. 

Westinghouse owned Union Switch ad Signal had already been the North American licensee of the Improved Saxby and Farmer mechanical locking system and has been using it in its crank style power interlocking machines since the 1890's. In 1901 the newly minted Westinghouse Brake and Saxby Signal Company was suddenly in a position to employ US&S's innovations in Commonwealth countries and came out with its Styles A and B interlocking machines, localized for British signaling tastes.

WB&SS Co Miniature Lever Frame in British Service

Like the crank (ie "Model 14") style interlocking machines in North America, the Westinghouse power frames had three distinct logical components inside the box. First, a mechanical locking grid of the S&F type handling route locking. Second, locking magnets that would lock lever travel based on the state of the electric relay logic. Third, electric contact spindles that would make or brake electric circuits depending on the position of the lever. 

Style K frame with mechanical locking grid.

Style K frame contact spindles.

A route conflict would result in a hard lock as steel bits in the locking grid would physically block movement. An electric problem like points out of correspondence or an occupied track circuit would create a soft lock as the lever was stopped by magnetic latches interacting with a rocker arm on the lever spindle. Anyone who has visited HARRIS tower and its functional Model 14 knows the difference in feel between hard and soft.

Magnetic "soft" locks on a Model 14 machine.

All of this was fine until 1929 when the 23 ton weight of 311 lever London Bridge Style K interlocking machine made Westinghouse Brake and Signal question the sustainability of the technology. Unlike North American pattern machines, the British pattern was less lever efficient, needing more physical levers to carry out the same functions. This not only created a weight problem, but also a size problem as the locking grid dimensions grew literally by the square of the lever count. While American railroads had the space to build beefy towers with wide dimensions, the "early adopter" British railways had harder clearance constraints, especially in major cities where large power frames were most likely to be built. For example the aforementioned London Bridge signal box had to orient its locking bed vertically, making the tower an extra floor taller.

 

London Bridge Signalbox

The solution to this was the Style L frame. Externally the Style L looks exactly the same as the Style K, however internally it is quite different with the mechanical locking grid being completely done away with and replaced by electric locking. the Style L existed as yet another step between the purely mechanical interlockings of the 19th century and the all-relay plants that would ascend in the 1950's. However for anyone wondering why an electrically interlocked plant would even bother with clunky miniature levers, there are some advantages. First it maintains a familiar UI and reuses many of the components that were already in production. Second, it still reduces the number of high cost safety critical railroad relays. The latter is not entirely obvious, but an electro-magnet that unlock a contact spindle that a human then turns, is performing many of the same functions as a vital relay without the same need for precision manufacturing. The website covering Westinghouse power frames has both patent and part information so I'll leave digging down into the fine details of how this electric locking was carried out as an exercise to the reader. 

Style L parts

Style L restored

Style L relay locking logic

The Style L completely displaced the mechanically locked style B and K frames on the main line UK rail network with a burst of new deliveries being made to the British Rail Southern Region between 1948 and 1953. Additional frames were delivered to South Africa up until 1960 with a final BR frame delivered in 1962. An interesting ramification of the Style L all-electric logic was a far greater degree of adaptability than those with mechanical locking. In North America, all railroads (except naturally the PRR) had to hire US&S to perform major modifications to the mechanical locking grid. However the Style L electric locking could be modified without the need for specialized tools and British Rail was able to manufacture quite a few "new" Style L plants using left over components or even spare frames obtained for redundancy purposes during World War 2. Even after retirement from main line service, both heritage and miniature railways have been able to adapt surplus Style L equipment for their own track layouts.

 

The final act of the Westinghouse power frame would play out on London Transport in the form of the mechanically locked Style N and Style V frames as their modest lever counts and subterranean placement didn't trigger the same sort of weight issues seen on the main line railroads. In fact, the last Style V frame, think a Model 14 automated by pneumatic actuators) was installed on LT in 1993! (Which goes to show just how wedded the British were to mechanical technology.) With the closure of Wellington A Signalbox earlier in 2025 and Liverpool Lime St in 2018, the last active Style L outside of preservation might be the signalbox at Maidstone East, which was fittingly the last new built Style L delivered in 1962.

Another One I Missed: Conrail BRIDGE Tower Closed and Demolished

Up through 2019 Detroit featured what I would like to call the Iron Triangle of staffed interlocking towers, DELRAY, NS BRIDGE and (Conrail) BRIDGE. As you might guess the latter two involve movable bridges over the River Rouge. In November 2020 I covered the closure of DELRAY tower as the last active long lever interlocking machine in North America, however I was then unaware that Detroit's iron triangle had already been broken with the closure of Conrail BRIDGE tower in late 2019. I'll blame the COVID era for it taking 6 years for me to notice the unfortunate change in circumstances, but I am going to post about it nevertheless so people don't have to sort through Facebook groups to learn what happened.

Conrail's BRIDGE tower benefited from a perfect storm of circumstances that saw it last well into the 21st century as an active block and interlocking station. First it was attached to a movable bridge, a thing that until recently required human presence, and second, it was part of Conrail Shared Assets, which is a 50/50 joint venture between NS and CSX creating a "Port Authority" type situation where slight inefficiencies can persist. Moreover, when FN tower in Trenton, MI closed around 2003, the operator at BRIDGE was given control of that territory becoming a mini-dispatcher of the Conrail SAO Detroit Line. This situation is similar to the operator at UPPER BAY tower in Conrail SAO's New Jersey division being assigned additional interlockings over the last 20 years or the CSX/Conrail operator at the Livingston Avenue Bridge acting as a mini-dispatcher for the Amtrak Albany Terminal (until Amtrak re-signaled the area around 2018).

BRIDGE had previously survived one brush with re-signaling around the time of the Conrail split where its S&F lever frame was replaced by a more modern unit function type panel. The efficiency movement finally caught up with BRIDGE in late 2019 with the tower being closed and then demolished between August 2019 and November 2020. The BRIDGE drawbridge was likely being placed under remote control as was the style with several other Conrail SAO operated movable spans at as of late. With DELRAY closing in 2020, this left NS BRIDGE, aka NS ROUGE BRIDGE aka ECOURSE JCT as the last remaining staffed traditional tower in the Detroit area (although in theory the drawbridges connecting Zug Island to the mainland also count as towers).

While not as iconic or as accessible as DELRAY, BRIDGE was still the second best example of an interlocking in the Detroit metro area. It's another sad loss in a city that hosted diverse mix of active and disused towers well into the 1990's.