Question posed to me regarding Alstom and Metro signaling

This question was recently posed to me in an Email discussion regarding Alstom and Metro's signaling systems, and I believe you all could possibly answer this better than I could. The questions were:

1. Is the Metro planning to replace the signaling equipment at some point in the near future?

2. How much it would it cost the Metro to replace their Alstom equipment?

3. Would it be possible for Metro to gradually phase out Alstom?

4. What portion of Metro's signaling equipment is done by Union Switch and Signal, and would it be possible / not too difficult for them to switch to Union Switch and Signal entirely?

What do you think?

"SchuminWeb"
This question was recently posed to me in an Email discussion regarding Alstom and Metro's signaling systems, and I believe you all could possibly answer this better than I could. The questions were:

1. Is the Metro planning to replace the signaling equipment at some point in the near future?

WMATA began a project to replace the signaling hardware in the oldest parts of the system some years ago. One of those areas was the area where the Fort Totten wreck happened. The wreck accelerated the replacement of the hardware in that area.

All of the hardware in the Silver Spring train control room was replaced after the room was flooded some years ago.

2. How much it would it cost the Metro to replace their Alstom equipment?

Don't know.

3. Would it be possible for Metro to gradually phase out Alstom?

Yes.

4. What portion of Metro's signaling equipment is done by Union Switch and Signal, and would it be possible / not too difficult for them to switch to Union Switch and Signal entirely?

First part of question, don't know, the easiest way to tell is to look for the USS&S logo on the Wee-Z bonds.

Second part of the question, not too difficult. There would be some issues with mixing Alstom and USS&S hardware during the replacement process. USS&S issued a bulletin recommending that certain parts of its version AF track circuit hardware not be mixed with hardware manufactured by other vendors.

My guess is that if Metro were to replace the Alstom signalling system with AnsaldoSTS (Union Switch & Signal- now a sister company to AnsaldoBreda), it would probably be in the hundreds of millions of dollars range. This guess is based on costs for hardware, labor, systems integration, testing and training. The system would probably only be converted 1 line at a time to minimize disruptions.

Logically, the Red, Orange, and Green lines would probably see total replacement of the signalling system before the Blue and Yellow lines if it comes to that. My reasoning is that these tend to be heavier used lines compared to the Blue and Yellow. I don't know if the new system would be CBTC capable but as long as they can keep good headways, and above all allow trains to run in automatic mode SAFELY, then it's a good fix.

There are train systems in the US and worldwide that do run a mixed environment. Here are some well known examples:
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1.) BART: The majority of this system has original Westinghouse signalling equipment. The most recent extensions use Bombardier CityFlo 550 for signalling and an interface allows the systems to work together. GE Transportation Systems had a contract to install a CBTC system. Due to numerous problems, overruns and lack of progress over the timeline, this project was shelved and all GE equipment was removed.

2.) NYC Subway: The Canarsie (L) line uses the new Siemens Trainguard MT system which is CBTC based. This was an overlay to the existing signalling system. All trains can run in the mixed environment on ATS/ATO/ATP, but only CBTC equipped trains (R143, R160) can use the CBTC portion of the Siemens system. Some of the numbered lines are expected to also get a CBTC upgrade. The Second Ave Subway which is being built now in Manhattan will be CBTC based but will allow mixed operation like the Canarsie line.

3.) London Underground: Portions of this system use legacy ATO systems. The Jubilee Line used a Westinghouse system but because of technical problems once the system was installed in 1999, the system was ripped out and replaced with Thales Seltrac (formerly Alcatel Seltrac) in 2009. This is just 10 years after initial installation. The cost to rip and replace converted to US dollars was well over $100 million. The Victoria Line is currently being upgraded with the Bombardier CityFlo 550 system and is being overlaid to allow a mixed environment.

4.) The Paris Metro uses a Siemens signalling system on Line 14 and it has completely driverless operation. Line 1 is being upgraded to be the same as well. The existing signalling system is being overlaid for this line so mixed rolling stock can still use the line during the upgrade process. The difference is that line 1 will convert their Alstom MP89 stock to driverless operation, thus being the only fleet capable of running this line once the upgrade is complete.

Here's a question regarding Metrorail signaling... What was the rationale behind Metro's use of dual red and lunar signal aspects, versus the typical red/yellow/green used on many other transit lines?

"pmisisco"
Here's a question regarding Metrorail signaling... What was the rationale behind Metro's use of dual red and lunar signal aspects, versus the typical red/yellow/green used on many other transit lines?

Those signals only govern the movement of trains through interlockings. There are there for redundancy.
At the time of the adoption of the signaling system used by WMATA the General Railway Signal signaling system was proprietary technology.
Lunar is used because in the event that one of the red lenses were to become broken a conflicting aspect would be displayed. If bulb behind one of the red lenses were to burn out the operator would still know to stop.

WMATA interlocking signals originally only displayed two aspect:
Red over Red = Stop and Stay
Lunar = Proceed at speed no greater then cab signal speed command

At the time it was believed there was no need for a third aspect. In resent years a third aspect as been added:
Flashing Lunar = Proceed at speed no greater then cab signal speed command through diverging route.

The above only applies on the main line where ATP is present. On track where ATP is not present:
Lunar = Proceed at speed no greater then 15 MPH.

It is also of note, WMATA is not the only transit agency to use Red over Red and Lunar aspect interlocking signals. They are also used on the Baltimore Metro.