The Sounds of Non-PRR Signaling

So I was about to post a second volume of PRR Signaling Sounds to highlight the importance of preserving both audio and visual history, but then I realized that I had a couple of non-PRR clips sitting on the back burner that deserved to see the light of day.



The first two were captured at some former Boston and Maine intermediate signal locations (BM mileposts 162 and 150) on the current Guilford Rail System Freight Main Line.  To the untrained ear they might sound a lot like the PRR signaling sound samples of cab signal code generators, and you would be right.  However why would cab signal code generators be used on non-cab signaled territory?  Well while the trains might not have been equipped with cab signal apparatus, the signaling department would use the 75, 120 and 180ppm codes sent through the rails as way to replace signal state wires on wayside poles.

When a signal location "heard" an Approach from the location ahead, it would know to display an Approach and transmit Clear.  When it "heard an approach medium it would display approach medium and transmit Clear and when it "heard" a clear it would display Clear and transmit Clear.  Hearing nothing would of course mean to display Stop and Proceed and transmit Approach. Later this technique would be updated with audio frequency signals instead of pulses of power frequency current, but at the time it was a clever way to use catalogue parts to eliminate costly pole lines.



Next we have a flashing Approach Limited signal at the 1950's vintage CP-LAUREL on the former Reading railroad Belt Line extension. A visit to the relay cabinet reveals a sound pulsing in rhythm to the flash of the signal, which of course indicates of an electro-mechanical flashing relay.  nothing super fancy, but it is a lot more reliable than what one might have to blink their Christmas lights on and off.  

Well, that's the extent of the non-PRR signaling sounds I have collected.  Don't worry all your PRR fans.  I'll be back soon with a second volume ;-)

All Askew - Remaining Users of Offset Auto Signals

Back in the day, setting the heads of a multi-headed signal on opposite sides of the mast was an effective way as marking a signal as an automatic.  Although the presence of a number plate was an accepted and inexpensive way of doing the same thing, reflector technology wasn't as advanced as it is today.  Some railroads even went as far as placing markers on single headed automatics simply to make them more visually distinctive.

However as time went on this practice, like many, was seen as a luxury that did little for safety.  Since the 1980's most railroads have placed their signal head in line, regardless of automatic status.  However there are still a few that have stuck with the old ways.

Canadian National / Canadian Pacific

The CROR signal ruleset is perhaps the more strict when it comes to offset head placement as it is the only option to designate a signal as automatic as number plates can also appear on absolute signals (on absolute signals plates are used to denote the lever number).  On single head signals left hand placement is used to provide the distinction in addition to absolute signals always having two or more heads.

Unfortunately, as far as I can tell this policy does not apply to CN and CP's United States operations, although some vestiges exist like these somewhat modern unilens signals on the former D&H.

Flordia East Coast

Regional operators often become museums of signaling practice and in this regard the FEC has preserved the practice of offset head placement.  The FEC also uses a robust cab signaling system so this is even more interesting single they could probably eliminate waysides entirely if they wanted to.

Former Boston and Maine (Guilford Rail System / MBTA)

Public transport agencies are another place where traditional signaling practices can live on and combined with a regional freight operator we have the former Boston and Main system as our final holdout on the use of offset signal heads. Some of the newer heads are a bit less offset than others, but it's clearly still a thing.

Well that's all the ones I am aware of at this point.  There are probably others (I'm omitting the Reading and Northern cause that's somewhat of a special case). Please let me know if you know of any that I have missed.

Better Know a Signaling System - Delaware and Hudson

Here in the inaugural episode of Better Know a Signaling System I am starting with something small to just sort of see how things go.  Actually brevity that is one of the interesting features of the old D&H signal set with only 10 total signal rules in their 1948 rulebook or 9 if you go by this undated chart that appears on railroadsignals.us

While 9 or 10 signal rules might sound like a lot compared to the 21 or seen in under NORAC or CSX, the D&H finds itself in good company with many other railroads not operating multi track main lines in and around busy urban terminals, especially those making use of route signaling.  The D&H is a very conventional speed signaling system designed for single main track operation with passing sidings.  If you remember back to my signaling dialects post you'll see that the D&H uses Y/Y for advance approach, R/Y/G for Medium Approach Medium, R/Y/R for Medium Approach and R/Y or R/R/Y for Restricting.  The R/Y/G Medium Approach Medium was made possible because the D&H made a point to use high signals at siding exits and R/Y/R Medium Approach was enabled by using only three headed signals at interlockings.  Here is an example of the three head policy that was still in effect up through about 2011 with brand new Unilens tri-heads installed on the former D&H Colonie Branch at CPO-5.

Unfortunately since CP went all Darth Crazy, two head signals are now being allowed to slip through as seen here at CPF-478.  Hmmm, looks like they are dumping right handed placement as well.

Contrast with the Boston and Maine's CPF-464 right across the Hudson River which has no problem making use of two headed signals and R/*Y* Medium Approach.

Another interesting practice that comes across on the 1948 signal chart is the use of offset heads for automatic signals.  A common practice back in the day, but one that is still followed in Canada to mark automatics instead of number plates.  It is not surprising that under CP ownership this practice was not challenged.  Although not a new CP install here is the MP 8.2 automatic on the Colonie Branch with the offset heads.

Staying with the 1948 chart we find a few interesting tidbits when it comes to dwarves.  Without slow speed indications the D&H could use G/R for clear and Y/R for Approach.  R/*Y* was used for Medium Approach to make room for R/Y Restricting.  The most interesting dwarf was Y/G for Medium Approach Medium, which I guess came up more than Approach Medium.  Single head dwarfs were limited to Y and R/Y Restricting and R Stop.  So kudos to the D&H for not installing Slow Speed turnouts I guess.

Aside from its dwarfs the only non-NORACy indication the D&H adopted was the Y/Y Advance Approach.  Of course with no slow speed signals it makes perfect sense.  There was also a R/Y/Y Medium Advance Approach, which was left off the Railroadsignals.us chart.  The thing is that when the Guildford Rail System (ex-B&M) purchased the D&H in the 1980's it did more than re-mile the main line from Binghamton to Maine.  In the 2007 CP Northeast US Timetable (towards the end) we can see that the signaling has gotten a lot more...conventional.  There is suddenly a R/R/G and dwarf G Slow Clear along with dwarf *Y* Slow App.  To compliment those Y/Y is now Approach Slow and *Y* picks up Advance Approach.  All the other old dwarfs are just plain gone except for Y/G, which is now Approach Medium.

So that's the story of the D&H signaling system.  It started out pretty conventional and then got even more-so after several new owners put their hand in the pie.

WALTHAM Tower: 1928-2013

Well this one snuck past me.  WALTHAM tower, which was creeping toward closure with a general resignaling project on the MTBA Fitchburg Line, went up and closed on June 1, 2013.  I wasn't keeping track of the project too closely, but I figured there would be ample warning from new signal locations and relay boxes and neither were in evidence as of March 2013 so either the signaling crews got that stuff in in record time or they did a less destructive splice job.

Anyway, WALTHAM was one of a dwindling number of US&S Model 14 interlocking machines still in service.  While all types of classical electro-mechanical towers have been suffering from attrition, US&S plants have taken it on the chin over the last few years with UNION, JAY, HALL, DUNTON, ALTO, NS BRIDGE, WB, CORK, BUZZARDS BAY and HN all getting tossed into the bin.  WALTHAM only survived this long due to the freak happenstance of it being made part of a B&M CTC project back in the 1950's or 60's.  This made it a shining example of modernization when the rest of the New Englande rail scene was terribly antiquated.  For example most of the NEC was still being run under ABS rules with block stations up into the 1990's.  Inside WALTHAM was a rather modest US&S Model 14 for the local plant and a 3-panel GRS unit level CTC machine controlling the line from the terminal area through to South Acton.

The local WALTHAM interlocking consisted of "Conrail Crossover" (two tracks going to single then back to two), with a couple of industrial spurs branching off.  Both "ends" of the crossover were fully protected by searchlight signals.  Despite the CTC machine most of the line was still run under rule 251 with the CTC being of the remote control only kind.

The brick B&M towers are solidly built and the MTBA has been kind enough to honor it with a historic plaque and several human interest pieces in local media so it is unlikely that WALTHAM faces demolition, but there will now no longer be any place in the Boston area where a lucky kid can get invited up to see a piece of history.  I am unsure if this is the MTBA's last active interlocking station as the movable bridges on the Newburyport/Rockport Line used to control local switches and signals although that may have changed.

If you are interested in my 2010 visit to WALTHAM tower you can find the full set of photos here.

If you are interested in a full Railfan Guide to the WALTHAM area you can find one written by a Position Light Blog collaborator here.