A Video Guide to French "Poste d'Aiguillage"

Getting information on interlocking tower / signalboxes outside the anglosphere can be a bit difficult not only due to the language barrier, but also cultural difference about railfanning and content creation.  While I found a comprehensive site on German towers many years ago, similar resources for French signaling had yet to pop up on my radar. This is rather unfortunate as I believe that France has a strong tradition of staffed towers and electro-mechanical era power interlocking machines.It also doesn't hurt that the standard SNCF model board design gives off strong PRR vibes.

Anyway, when doing a quick Youtube search on "Poste d'Aiguillage" I found a somewhat recent public information film detailing the many styles of French interlocking machine, running the gammut from mechanical lever frames to VDU area interlockings. It even gives a shout out to a North American pattern Taylor (GRS) machine. You can watch the whole thing for yourself below.  Enjoy!

 

 

 

A Tale of Two British Railway Signaling Public Information Films

 The UK is well known for a certain style of public information film that were professionally produced up through the 1980's. A couple go into great detail into the ins and outs of Railway Signaling and served as both a way to increase the public standing of the nationalized railways network in a time of both austerity and modernization and as a recruiting tool to bring new workers with new skills into said modernizing rail industry. 

The first film, entitled Electrical Engineering on the Railway and produced in 1962, falls more on the recruiting side of things as relay based "electric" signaling replaced largely mechanical manual block signaling on the busiest unresignaled main lines of British Rail. While this may been a bit odd as North American signaling has largely discarded purely mechanical signaling by the 1920's, Britain might get a bit of a pass given the toll a pair of World Wars took on its railways and economy.  Point of note include:

• A general lack of safety practices including, but not limited to protective clothing and burn pits for demolished signalboxes.
• The appearance of pneumatic point machines and North American supplied GRA Model 5A electric point machines.
• Rather flimsily looking track circuit bonding wires.
• The continued construction of brand new mechanical lever type interlocking frames.
• Some components of interlocking hardware being hand forged in house.
• A general use of North American pattern glass case plug-in and shelf type relays.
  

The second film, entitled Points and Aspects, was made in 1974 and shows the leap in British signaling from what one might call an updated basic CTC plan to something that was making far more use of computer and telecom technology to enable the so called wire area "Power Box" era of British signaling with as much automation as 1970's technology could muster..  This film is definitely trying to sell the public on British Rail not being a basket case and is worthy of their continued support and patience.  As a result an emphasis is given to the higher tech elements.

What is especially fascinating is that these two videos appear to span the moment when  the UK went from a very North American leaning approach to signaling technology, to a more European approach. Despite very different operating practices, North America and the UK had very closely aligned signaling supply companies with both GRS and US&S licensing UK technology and then supplying their own products back through local subsidiaries like Westinghouse. In the 1970's we are seeing the end of the glass case relays and Model 5 and M3 point machine that stared in the 1962 film.

British Power Signaling Channel Heads Down Under

About seven years ago I discovered the Youtube channel of one Ian Ives, who had posted a variety of VHS era videos from inside British power signalboxes (PSB's) in the early 1990's, such as this one of Glasgow Central.  Well as the way things tend to go I lost track of the channel until a recent keyword search brought it back on my radar.  It turns out that Mr. Ives has had quite the exciting career as over the intervening years he posted a number of videos from Australian signalboxes.  These are especially interesting due to the mix of British and American influences. 

For example he has some video of the operation of a local Australian copy of the GRS pistol grip style interlocking machine, only in Australia it is paired with pneumatic point machines!

A British style lever frame at Hurstville.

A British style panel controlling a US style CTC layout at Salisbury.

A British style miniature level power frame at Sydenham.

An interlocked and manually controlled grade crossing with a modern panel interface at Parramatta Road.

And finally a modern signaling center at Wollongong.

Just like in the US, Australia has been seeing its own drive towards the elimination of manned signalboxes and non-video interfaces so most if not all of the videos capture railway infrastructure that has been now lost to time. 

In addition to the tower content, Mr Ives has also posted a number of industry training materials including instructions on manual operation of every model of power point machine in service with the railway including pneumatics. 

Please check out the channel as many of the above example videos came in multiple parts. New videos continue to be posted so it might be worth subscribing to.

Belorussian Signal Sabotage

After some initial reports back in early March, it has been more extensively reported since the Russian withdraw from the northern from that Belorussian railway workers and anti-Russian activists had been conducting extensive sabotage operations on Russian supply trains transiting their county with specific focus on the signal system as a method of causing delays without causing death or injury. 

In a previous post covering the nature of ex-Soviet railway signaling I mentioned that the rail network uses a very strongly "station based" interlocking system.  This means that most major stations (think any large community with more than 1000 residents or so) will have crossovers and multiple siding tracks as well as industrial leads and possible junctions.  Between these station interlockings are simple automatic block signals, either single or bi-directional.  The following Belorussian cab ride video shows off the system well along with what appears to be a voice enunciated cab signal system?

Anyway, most of the articles implied that the signal attacks were occurring against undefended ABS signal locations away from prying eyes.  While this would certainly cause some delays, the simple nature of the signaling involved could likely be repaired quickly or worked around with absolute block operation.  The juicer targets of interlocking relay rooms appear to be a much tougher nut to crack as unlike North American interlockings, the location of the central instrument houses is hard to determine as they are not obvious from the cab.  This implies they are in the station or one of the station's outbuildings, which would be far harder to sabotage due to the presence of the public, security personnel, railway staff or CCTV monitoring. The article even goes on to say that the attacks became harder to pull off as local security forces were put on notice.

Because of the old school nature of the signaling, most of the setup would be immune from cyberattacks with the possible exception of any CTC system that might use computer aided dispatch or public networks for communication.

Video: Soviet Signaling on the Russia - Ukraine Border

 Today's video post is ripped from the headlines!  I'm sure many of you are familiar with the past and current conflict between Russia and The Ukraine. Well, the 2014 disagreement had some implications for the Moscow - Rostov-on-Don railway line as some of it actually runs through Ukrainian territory in the vicinity of Chertkovo. To avoid being in any way beholden to the Ukrainian government, Russia built an entirely new bypass between the towns of  Zhuravka and Millerovo.  While trying to figure out how this trans-national rail segment functioned, I found some reverse railfan window video footage that not only showed the area, but also provided a taste of Soviet style railway signaling, a versions of which are also used in former Eastern Bloc states and China.

While I'll try to do a more in depth review of Soviet railway signaling later, a brief primer can be found here. It's an interesting system based on the station and main line system where stations have crossovers and siding tracks and can sort of be considered within interlocking limits.  Here one sees more complex sation signals where the upper head provides information about the next signal, while the lower head provides information of any immediate diverging route, plus stop.  Between stations an ABS 251 system predominates with Approach type signal indications being given by flashing Green and Yellow aspects.  There's a lot of incomplete information so I'll try to get a more complete picture in the future, but for now, enjoy the video.

German Stellwerke Blog and Its English Mirror

Although they have been prominent in my sidebar for many years, I wanted to give another shoutout to the German equivalent of this blog, Von Stellwerken und anderen Maschinen, because the author has been trying their best to provide English translations of some of the key articles in a paralell blog, Of Interlockings and Other Machines. 

 

While the former has hundreds of posts from over the last 10 years and the latter only about a hundred, the effort to provide some translations is particularly important in this niche subject because niche subjects have a habit of confounding automated translation tools like Google Translate.  While the Germany version of the site is still pretty readable if you stare at it enough, the large sample of English translation pages now on the mirror site allows one to really get a handle on how Central European interlocking machines and signaling systems work.  If you are looking for something to do on a cold winter weekend I highly recommend both of these websites as the author has a seeming endless supply of behind the scenes photos, both of in service equipment and preserved.

Explore French Signaling on the Aubrac Line

 A short while ago, a video on the least used passenger rail station in all of France piqued my interest in the Aubrac Line between Beziers in the south of France and Clermont near the center.  The mountainous line was electrified with 1500v DC in the 1920's and retains much of its original electrification infrastructure including catenary supports and substation buildings.  The line is a good way to see how French railway signaling works in practice as much of the line is single track running under manual block operation with 5-10 mile blocks between stations that also serve as passing points.  Some of the cities along the line night have some shorter automatic blocks so there is some variety.  

The line is also equipped with Le Crocodile ATS system and the more modern KVB balise based system, which is interesting.  Because of the manual block and long gaps between passing points, things can get a bit dull at times, but aside from looking for the 1500v DC substations one can try to figure out if the line uses track circuits or axle counters for train detection.

 In general, the library of cab view videos from Europe is far more extensive than those from the US.  This might be due to the larger number of rail workers and single person operation that limits snitching. Whatever the reasons, its a great resource to help learn other signaling systems.

 

Japan Shows Us How It's Done (again)

I found an interesting puff piece on Youtube showing off Keikyu Railway's method of supervised train dispatch on their 87km network on the Miura Peninsula south of Tokyo.  Similar in feel to Chicago's CTA or the NYC Subway, the dispatch system shuns centralization and computerized control for the sake of service quality and fault tolerance. 



The line is divided into 20kn sections, each with a master tower located at a segments' most important station.  The interface is a second generation unit lever panel (not N-X) and the well trained operators are able to achieve an astonishing level of throughput that includes dynamic trainset management.  Through operational skill and a signaling system that doesn't get in the way, train movements are scheduled down to the second.  The video also describes how the human-focused system has a high degree of fault tolerance because each master tower has the surge capacity to adapt to all types of failure that would tend to overload a remote dispatcher or dispatch office.  Still, a remote chief dispatcher is available to assist and coordinate if the need should arise.  The result is Keikyu having the one of the highest on time performances in Japan.

Of course in North America we don't care.  Traffic levels are low and delays are typically seen as a cost of choosing transit. Our levels of training and operator competency require technical guard rails like PTC and fixed trainsets that further reduce efficiency.

Commonwealth Signaling Diagrams

Found two interesting websites with some top notch non-North American signaling diagrams.  The first is called SA Track and Signal and features all manner of track and signaling diagrams covering a significant portion of the Australian rail network.  Australia is a government owned model with lines being leased or trackage rights assigned.  This site looks like it caters to crews that need to qualify on unfamiliar lines.  Everything is in full color PDF's that starts at the regional scale and allows one to click down to the individual track and signal diagrams.  Signals are represented in full detail along with signs and other operating information, however these are not interlocking charts and switch numbers along with other signaler oriented information is not provided.

The other site I found hosts UK diagrams from the Glasgow suburban area, but the website itself is not railway related.  That is because it is a public access freedom of information site that put up a number of track and signal diagrams that were requested under a public information request.  These are much like the Australian diagrams with full color representations of the signals, but there is no convenient tree of linked maps.  The low level diagrams are provided on a web page list and you have to sort through them yourself.  These diagrams do include track and turnout speeds. 

Diagrams such as those apparently exist for the entire UK for use as training aids, but are not often made public due to misguided terrorism concerns.  Keep on the lookout because they are widely distributed and do show up from time to time in Google.

Bad Signaling at Bad Aibling

The Bad Aibling rail accident was a head on rail collision that took place on February 9th, 2016 on a single track portion of railroad near Bad Aibling Germany.  As of this writing the investigation is pointing towards human error on the part of the signalman and, more specifically, the fact that the signalman was playing a game on his mobile phone around the time the events of the accident occurred.  Now. while phone distraction has played a role in previous rail accidents, in this case I believe the true culprit is the design of the German railway signaling system itself and any claims of distraction are simply an easy answer.

This tower operator is distracted, but not unsafe

First let's deal with the issue of distraction.  Unlike operating a vehicle, operating a tower or dispatch interface does not require constant attention.  Of course it is better to have someone paying attention, but it is not unsafe and moreover, distractions are already built into the job.  Operators frequently have to use the restroom, eat meals, talk on the phone to other railroad employees or even leave the tower to deliver train orders.  In a job filled with distractions, the whole point of the signaling system is to prevent distraction from leading to accident.  It is a fundamental principal of railway signaling for things to fail safe.

German Zs1 Signal

The mechanism that allowed two trains to end up in a cornfield meet is the Zs1 signal, shown above.  Known as an "Ersatzsignal" or Substitute signal it is placed below a "main signal" and lit upon command of the signaler when the main signal cannot be displayed normally.  Many in English speaking rail circles have described it as a Restricting or call-on signal, but that analogy is not entirely accurate. In practice it is more like a manual block clear of the type that can still be encountered on the LIRR.  Trains pass the Zs1 and proceed through all turnouts at no more than 25mph and before they can increase to normal speed .  Some sources state the 25mph limit applies to the next main signal, but a majority say normal speed and that would agree with the behavior of the second train involved with the accident.

Zs1 Displayed for a train movement

 The Zs1 signal is displayed when, for any reason, the main signal governing movement into a section of track, cannot be displayed.  This can be due to a bulb out condition, an axle counter miscount or any other problem with the signaling system.  As far as I can tell, the Zs1 guarantees route locking only.  In most rail systems around the world, when the signal system fails trains must proceed on sight prepared to stop short of an obstruction or other problem.  This is because even in the case where the cause of the failure is known, that doesn't mean a second problem might exist.  Because the situation of compound failures can lead to accidents, in most of the world a substitute signaling system must replace the automatic one to relieve trains of this burden of traveling at Restricted speed .  As one might expect, performing this task can be quite involved, requiring multiple signalers and communicating the fact to many trains and qualified employees. However in Germany all it takes is a button press to light up the Zs1.

Bad Aibling Stellwerke

In North America there is no signal that can be displayed into a CTC block where traffic is set in the opposite direction in the same way a Zs1 is used in Germany.  You can't even give a Restricting against the flow of traffic, necessitating a permission past stop procedure and even then the train will continue to be limited to Restricted speed.  The permission past stop procedure involves speaking to the locomotive engineer, usually over an open radio channel.  Yes. dispatchers in North America can screw this up, but the procedure takes time, requires two persons and requires the operator or dispatcher to pay attention.  In Germany the signaler presses a button and the train operator heads on his way.  When used for routine problems like bulb out or axle miscounts the process can become rote and the procedure can be shortened or skipped entirely.

The Zs7 Caution signal is the best analog to North American Restricting

Unfortunately I don't as of yet know what the Zs1 procedure involves, but I from what I have read it consists of ensuring that the block is actually free of obstructions.  A newer signal, Zs7 Caution, is used in places where the signaler is unable to positively determine block occupancy and does in fact require the train receiving it to proceed at Restricted speed, but the problem of actually setting a route against traffic remains.

313 absolute signal where the Zs1 was displayed before the collision. Annotated version.

While misuse of the Zs1 was the ultimate cause of the accident, there were a number of other systemic factors that contributed to it.  First, closed channel radios are employed  in theory to prevent "confusion" over who is speaking to whom, but the end result is that train operators are kept in the dark.  Furthermore, in the case of the Bad Aibling accident closed channel radios actually prevented the signalman from being able to stop the trains involved with a radio call because he forgot the correct emergency broadcast code to use.  You know, as opposed to pushing transmit to talk.


Second, the use of axle counters as a cheap alternative to track circuits, only serves to further ingrain the manual block thinking.  Detecting track occupancy without track integrity only perpetuates the inability of distant signals to stop trains.  Moreover, while axle counters are prone to failure (or miscount), just like track circuits, the signaler is able to reset the problem on his own with a button, instead of needing a maintainer to fix it.  While some can see that as a feature, it removes a valuable form of two person control.  Again, fixing signal problems via the interlocking panel becomes habitual and eventually an accident happens.

Panel blocking was a basic way the PRR made operators think twice before bypassing signal protections.

Most signaling systems have their single point of failure.  In North America there isn't anything preventing an operator or dispatcher from giving a bad Form D and running a train into another on a stretch of single direction ABS track.  However for the last 50 years we have been on a quest to eliminate ABS and replace it with something where such a mistake cannot be made because the technology prevents it.  Germany however, despite all its fancy train protection systems, flank protection and signal overlaps, is still burdened with 19th century thinking when it comes to block systems.  As a society Germans are really good at following procedures so therefore these sorts of accidents are rare, but allowing something like the Zs1 still tempts fate and every so often you get burned.

Note: This is my 261st post.  Yay for important milestones!

British Power Signal Box Video Tours

On a British signaling forum I frequent, a signaler known as Ian Ives uploaded a number of VHS video tours he made of some London area British Power Signal Boxes (also called Panel Signal Box or PSB) back in the 1990's.  For those of you who don't know, a PSB is roughly equivalent to the type of interlocking tower that was largely passed over in North America in the evolution from single interlocking towers to dispatch offices. They are basically what the NYC Subway calls Master Towers.

Popular in the UK between the 1960's and the 1980's, they replaced most of the electro-mechanical interlocking towers in busy urban areas as well as scores of pure mechanical towers.  PBS's contained large NX style model boards with light green tiles.  Their most high tech feature was automatic train description using small LED or CRT display boxes, which in the 1960's was quite a feat indeed.   While well documented pictorially, there are relatively few video records of how these panels were worked so check out these great resources.

If you like these, make sure you visit and/or subscribe to Ian's channel here.  If you would like an official tutorial on how these panels worked, you can find it here.

Addington Signalbox Closes

More news from the land down below down under.  On August 1, 2015 the last manned signal box (aka interlocking tower) on the southern island of New Zealand closed.  Addington signalbox is located in Christchurch, NZ and over the years it had come to control much of the Christchurch terminal area.  Centerpiece of the tower was a 1930's vintage McKenzie and Holland Style A electro-mechanical interlocking machine with the extended territory being controlled from unit lever CTC panels. The tower is also responsible for gate operation at a number of nearby level crossings.  Here is the diagram of the Addington area with the original territory located at the lower right.

Since it was built Addington interlocking has changed dramatically leaving only a handful of active levers on the old interlocking machine. There is comprehensive gallery of interior photos located on Facebook, but for those of you without FB accounts you'll need to settle for this 2008 video posted on Youtube as I was unable to find any other photos.  According to my count there are 11 active levers, 8 signal, 3 switch and 1 lock. The frame looks similar to GRS Model 5 just with miniature levers replacing the pistol grip slides.  The model board covers the territory from Linwood through Middletown South including intervening interlockings at Middleton North and Christchurch.



The New Zealand signaling methodology is more similar to North American practice than to UK practice with speed signaling, permissive signals, CTC and atomic interlockings.  Unfortunately NZ is also like North America in its general abandonment of manned interlocking towers.  Today all signaling on the south island is now remote controlled from Wellington on the North Island.  Remaining north island towers like Petone are also closing at a steady clip.  I urge anyone who may be traveling to New Zealand to check out some of its fading railway heritage in addition to its natural beauty.

Call it the "Ohio CPL" and Petone Update

I believe I have mentioned this before but CSX is taking the "Baltimore" out of B&O CPL in its latest re-signaling project that will remove the last CPL signals from Baltimore City.  These are located in the Bailey's Wye area and comprise CAMDEN, HB TOWER, BAILEY and LEADENTHALL ST interlockings.  BAILEY is notable for its 3-track B&O CPL signal bridge and all of them were upgraded in the early 1990's in conjunction with the Camden Yards Sports Complex project. What a waste both in terms of hardware and cultural heritage.

Yes, that signal on the left is displaying Medium Approach Slow.

The cutover is scheduled for President's Weekend so if you haven't gotten your photos already this is your last chance.

In other news BNSF dumping all the classic Northern Pacific searchlight signaling on the Cascades route between Seattle and Portland.  This includes the popular cantilever masts in the Vancouver, WA area.  Get your photos quickly.  The Coast Starlight is probably the best option.

Finally, a friend of the blog in New Zealand went out and took some photos of the now closed Petone signalbox before it closed its doors for good.  I have thus updated my short post about Petone with her work so thanks so much Sophisa.

Petone (New Zealand) Signalbox to Close

I don't normally do foreign (non-North America) signaling news simply because there is so much of it and it would require all sorts of explanations of how such and such technology compares to what most of the other readers of this blog are familiar with.  The small signalbox at Petone, NZ is special because not only has it been very well documented by the Hutt Valley signaling page, but also because both New Zealand and Australia see a lot of North American style signaling practices, even if it is by way of UK licenses of traditional US&S and GRS technology. Also like North America New Zealand is rapidly running out of manned interlocking towers so the loss of this one is worthy of note.

Petone signalbox showing the 67 signal displaying Clear for a Wellington bound train.

 The interlocking tower, or Signalbox in commonwealth terminology, is almost entirely North American in design with a familiar black CTC-style desk console and searchlight signals out in the field.  It is an all relay plant that today control controls two crossovers and one turnout for a branch line.  It is stunning that it has held on in service for as long as it has, even with just a single 12 hour shift.

 As you can see here in this photograph of the console the amount of territory and interlocking appliances under Petone's control has shrunk dramatically since it was built in the 1950's, especially in the Petone Station area.  I should also mention that Petone is CTC in the PRR fashion with remote interlockings on ABS signaled lines instead of lines with actual traffic control.

Click here for a higher resolution image.

Unfortunately, but not surprisingly, Patone box is being re-signaled and is finally closing on Christmas Day, 2013.  More unfortunately is that the new interlocking is going to use "tip over" LED signals and axle counters instead of track circuits because its always better to infer the location of trains than, you know, DETECT THEM.

68 reverse direction dwarf signal and its new replacement.  The line will be moving from ABC to CTC.

 Anyway if you happen to live in New Zealand make sure you get out there and grab some photos before the box closes.  You have no excuse thanks to all the nice sunny weather this time of year.  If you are interested in the re-signalling project check out this very detailed page here:

http://valleysignals.org.nz/petone/newpetone.html

UPDATE:  Friend of the blog  Sophisa, who lives in the Wellington area, actually went out and took a number of very nice photos for me including the outstanding high res CTC console shots.  Just goes to show what the ladies are capable of in the sausage fest that is railroading.  Thank you so much!!  You can find all her photos here.

What's going on here o.0

DOUBLE UPDATE:  Found a photo of the "new" PETONE CTC console.

Good News From Down Under

Actually its not Australia I'm talking about today, but New Zealand.  Recently I had heard that a re-signaling scheme had been carried out on the Hutt Valley Line, the old signals of which actually had their own website.  Well today I learned that the project only re-directed CTC control from a local US&S panel to a dispatch office in Wellington.  Even better all the original relay based CTC interlockings were left untouched.

Ok, that's pretty minor, but the news gets better.  While the US&S Model 14 interlocking machines in the US are marching towards extinction with the recent re-signaling projects at ALTO, UNION and WB, US&S parent company Westinghouse did sell power frames based on that same technology overseas to mostly British commonwealth countries as the style L, K, N and B miniature lever frames. They are basically US&S frames just with the levers working back and forth instead of side to side (so the poor signalmen wouldn't get confused ;-) )  Anyway these are about as rare as their breathern here in the United States with only a handful of examples still in main line operation in the UK and South Africa.  Well today I learned that again, despite some minor re-signaling, not only is the large Style L frame controlling the Wellington, NZ terminal still in service, but it was actually upgraded with three flat panel displays replacing its old bulb lit model board.  Talk about a clash of technologies!!

Not only does that frame survive, but so do three others on the North Island Main Trunk at Tawa, Porirua and Plimmerton with Porirua being in use daily and only Tawa being "generally known" about.  Here is a page that has some more up to date information on the Style L machines in New Zealand.


Anyway its nice to know that even if power frames vanish from the United States they can still be found in some nice vacation destinations overseas.  And then if those go you can always check out the pneumatically actuated Style V machines installed on London Transport up through 1999!!