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Tuesday, April 25, 2017

Swindon Power Signalbox Restoration

Hopefully most of you are familiar with the excellent job the crew at HARRIS tower has done reactivating its US&S Model 14 interlocking machine with the help of a lot of PLC's and Train Dispatcher 3.  Well over in the UK a project is afoot  to do the same thing to the old NX panel from the Swindon Power Signal Box.  The "PSB's" were a generation of British area signaling control centers that replaced the most hard pressed mechanical tower in the 1960's and 70's.  They used a lot of relay logic to implement push button N-X operation and many eventually came to feature integrated train description.  A tour of Swindon PSB can be seen below.

Swindon, like many other PSB's, are being removed from service because many of the telecon grade relays that drive the user interface and other ancillary logic are becoming nearly impossible to maintain.  Here below is a video showing the "domino" style panel board being re-assembled after it arrived at its preservation site.

Here is a brief demo of the old panel UI hooked up to some modern electronics.  And yes that is indeed the Danny Scroggins who is so well known for his comprehensive documentation of vintage British signaling and signalboxes.

Of course there is an entire Youtube Channel devoted to the project, with videos like this one showing the progress of the custom PLC components.

In fact the panel has its own preservation society and as of now they are projecting an grand opening date of June, 2018, plenty of time to score that cheap transatlantic airfare.

Tuesday, April 18, 2017

The Many Signals of Penn Station

In the first decade of the 20th Central, a number of transit mega-projects were under way in the United States.  Two of the most well known are Grand Central Terminal and Pennsylvania Station in New York City.  In addition to being civil engineering marvels, they also employed the latest technology in railroad signaling, which included both power operated interlocking machines and, gasp, electric signals.

I've mentioned before  how surprisingly difficult it was to create the first 100% electric railroad signals.  This was because high intensity electric bulbs (necessary to be seen under daylight conditions) of the time would have an impractically short service life and also because electric power was in vary short supply in might of the country.  However the projects of Penn Station and CGT did not suffer from these two limitations because they were underground, where it was dark all the time and they had reliable supplied of electric power on a 24/7 basis.

Right: Old GCT signal.  Left: New GCT Signal

Fast forward 100 years, while Metro-North replaced all the original 1913 signals in Grand Central, across town at Penn Station, the thrifty stewardship of Amtrak had resulted in much of the 1911 not only seeing the 21st century, but doing so just above the heads of millions of dashing commuters.  Union Switch and Signal, naturally, supplied the signaling for the entire projectfrom the interlocking machines to the relays to the signals themselves.  The signals were a custom job that, as far as I can tell, weren't used anywhere else since the electric age kicked off a rapid period of innovation that saw both searchlights and position lights entering the market in just a few years.

The Penn Station Signals consisted of a tri-light patterned upper head with G+Y+R lamps and then a lower head with an additional two R+Y lamps in a vertical orientation. Since the station trackage was all run at what is today known as "Slow" speed (15mph), there was no need for any of the more complex aspects such as Medium Clear or Approach Medium.  Two lamps were illuminated at all times to provide R/R Stop, Y/R Approach, G/R Clear and R/Y Restricting.  In the tunnels approaching the station Y/G Approach Medium and Y/Y Approach Slow indication were employed.

The Penn Station signal was a single cast iron housing with lovely rounded corners.  Due to the close clearances the signal was designed to be suspended from above, this would result in some awkward "gooseneck" mast mountings as I will show later.

From behind we can see how the signal was divided into two lamphouses, each with its own cast iron cover plate.  Note the very very old style US&S logos and markings.  Remember, all these pictures were taken in 2017, 106 years after the signals were installed.

Here we see a trio of 1911's litterally hanging out next to the now closed 'C' interlocking tower at the east end of the LIRR tracks.  The colored glass lenses are still vivid even to this day, probably because they were made with all sorts of now banned compounds.

Now if you think it is time to move on to the modern signals, you would be wrong as there is a second pattern of 1911 signal scattered about the complex.  One such example is the famous 122W "gooseneck" signal at the west end of track 7 (remember, I said they can only be suspended from above).  If you look closely you'll also notice that the G and Y lamps on the upper head are spread farther apart than on the standard Penn Station signal.

Now these "googly eyed" signals could have been some experimental or pre-production batch, but if you want a more satisfying answer I might say that this pattern was intended for ABS use in the tunnels.  The spread upper bulbs designed to simulate the offset heads of automatic signals.

Moving into the modern period we catch this Amtrak experiment with Safetran Unilens signals hanging at the east end of track 14.  Because of the problems with the Unilens that I have previously discussed, JO signal 566E appears to be an isolated incident.  So what then is the modern replacement for the unique 1911 signals?  Well actually its a modernized version of the unique 1911 signals.

Amtrak had suspended a pair of Safetran modular dwarf units below what may or may not be a Safetran lamp housing for a target style tri-light signal. The result is a nearly perfect drop in replacement for the cast iron 1911's.

Here we have an even more compact arrangement that omits the space for the "not in conformity" number plate on an absolute signal.  Hey, you can't say it doesn't work.

Here we can see how new and old compare at JO interlocking with the modern 564W signal displaying Restricting right next to the vintage 566W displaying clear.  The modern lenses are clearly larger, but both get the job done well.  In general, the former outdoor portion of A interlocking has been modernized while one is more likely to find 1911 signals scattered around JO and C, however there are many exceptions to those "rules".  Of course I'm also omitting the smattering of PRR position light dwarf signals scattered around the yard areas, but you've seen those before.

Anyway, I hope you've enjoyed this little tour of Penn Station.  Most of these photos were brought to you by the magic of modern smart phone cameras that excel at taking photos in low light conditions and also won't attract swarms of police and security officials.  Next time you are in Penn Station I urge you to look up and if you see something interesting, document it.  After all, nothing lasts forever.

Wednesday, April 12, 2017


So I have a brief news update here.  While riding the 2016 Amtrak Autumn Express I noticed that NS had advanced their Reading Line re-signaling effort to CP-ALBURTIS from the west.  It seemed that they would go and cut in the first half of the signaling and then work from CP-ALBURTIS to CP-BURN for the next season.  Well it not appears that they are going to do the whole conversion in one extended go as new signals have now appeared at CP-BURN.  Guess I'll have to schedule another field trip :-(

I am currently processing the photos from this trip and you can find the Lehigh Line portion here:  It's a real mixed bag od NS, Conrail and even a few surviving LVRR signals.

05/20/2017 UPDATE: I returned to the Allentown area to find that the re-signaling project has caught up CP-ALLEN and CP-HAM on the Lehigh Line. CP-JU and CP-CANAL so far appear to be unaffected.

Wednesday, April 5, 2017

Now For Something Completely The Same (#1AESS Retirement)

I just got word that on or about right now, the last active AT&T/Western Electric #1AESS telephone switches (generally confined to the former SBC territory) are being taken out of service.  This matters because the railroads are currently speeding towards the completely sterile, 100% digital environment that the telecoms have apparently just achieved.  Unlike railroads, which still have a few instances of electro-mechanical interlocking machines and hundreds of relay plants in service, the teleco's banished the last electro-mechanical switch from their network back in 2002, with the majority of the work taking place between 1970 and the 1990.  Back in the day, there was an entire scene of people who would go from place to place, listening to all the strange ways that the phone system functioned.  Today this sort of task would be a fools errand because everything is the same across the entirety of North America. 

Until recently, the #1ESS and #1AESS were the only exceptions.  Sort of like the 3400 series L cars or the NYCTA R68's and their cam-controlled DC propulsion systems, they were analog machines build in a digital world.  While the higher order functions were computer controlled, the actual switching was carried out using reed relays.  It's basically the N-X CTC panel of telephone switches with a computer bolted on to handle some of the route selection functions.  Even then, the attached were old school enough to fall into the "cool" category. 

Like with classic railroad signaling surviving on out of the way branch lines, the #1A aand #1 switches held on due to the recent wholesale divestment in copper wire / landline telephone services.  Still, the economics eventually because just too lopsided in favor of replacement and AT&T canceled its support contract with Western Electric successor Lucent in 2015, with an expected retirement date of 2017.  

This is why it's so important to get out and capture the classic technology before its just collecting dust in the corner of a museum.  In a few decades just about everything will be software running on some bog standard processor mounted on a raspberry pi.