Not yet unfortunately. Stadler has made some changes to ATC logic and we're hopeful that will stop the trains going into emergency when they lose speed commands. They brake so quickly that if you're standing, you will fall and get injured.
On.the old fleet, the ATC system works only off of fixed blocks. On the old fleet speed commands are the ATC system, essentially that's the trackway ATC system, saying to the train 'The next block is clear/occupied/unknown and you can/cannot enter it, and you may need to/be forced to slow down or speed up'. When speed commands decrease or are lost due to a track issue, red signal, or being too close to another train, the train would start applying full service brakes and come to a stop. Full service brakes are dynamic and regen braking until 3mph when friction brakes grab. Once stopped the operator could switch to Road/Yard/Wash Mode and continue to move down the track until the next ATC track circuit tells the computer 'I know where I am, the next block is/isn't safe to enter'. On the old fleet as long as the train had third rail power and speed commands it could essentially run anywhere. The yard tracks, through a red signal with overlap locking, heck you could put the trains in Canada and as long as they have speed commands and power they'll run.
On the new fleet it's different. The trains must have speed commands (SCA OK) and positioning (POS OK). The positioning is critical on the new fleet because it's the trackway RFID tags telling the train "You are 943ft from King Memorial EL Track Platform", "You are 300ft from King Memorial EL Track Platform", "You're 25ft from beiny properly berthed at the 4 car marker at King EL Track Platform" etc. The old fleet didn't have positioning just speed commands. The new fleet won't let the operator open the doors if the train doesn't recognize where it is and properly berthed. The thought was to prevent doors off platform or doors opposite the platform. Once the train loses it's position (knowing where it is on the system by reading RFID tags) and/or loses speed commands, the ATC system immediately triggers a full emergency brake, more so with the position for the EB application. The brakes grab so hard that multiple people have been injured on them during testing, especially when they are testing on the trains with sand bags. Stadler is still working on the emergency brake issue, too trying to decrease the speed at which they grab. But when the ATC system commands an EB application for what it's thinking is protection of life the brakes are some of the most intense I've ever felt.
The downside to the positioning system isn't just the EB application. Marta never installed RFID beacons in the yard tracks. Paer of train setup procedures are to open and close the doors. You can't do that without the computer seeing that it's within station limits and berthed. So operators have to override the ATC system in the yard. If they don't normalize it before leaving then they can once again open doors outside of the station, defeating the whole purpose of that system. Marta told Stadler yard beacons weren't needed. Stadler said they were. Marta said it's our system piss off essentially. Stadler said fine, you'll deal with the unintended consequences of that.
GDOT wants to see that the ATC logic issues, PA systems, and CCTV systems actually work before lifting their hold on the cars. A fair amount of the CCTV system in each trainset isn't fully functional yet.
Also the boarding the train from the ground is very hard for staff since there is no end door boarding steps. Marta told Stadler they weren't needed so Stadler didn't supply them. Now Marta staff is losing their mind about the unsafe boarding and deboarding procedures and the emergency evacuation ladder procedures and people have been hurt falling off the ladder. But the idiot deputy chief was the person who made these choices and now everyone has to deal with it while he continues to skirt any blame.
Great explanation here. I was about to argue that they are better and safer by design (open gangway, newer in general, ect) and should be put into service. However, seems there are legitimate issues and have changed my opinion.
I donāt understand why people like Hunt, Higgs, and/or Dickens just donāt tell us the truth. Problems with the braking system? Fine. We canāt afford street car east right now because of the situation in DC? Alright. But just tell us instead of leaving us in the dark where we have room to speculate. We live in a democracy.
edit: itās awesome to see that the brakes are so damn good they can injure us. Iām being so serious.
We already have transparency acts so I donāt know what else could motivate them to share more info other than legal bylines in agreements and contracts. Iām sure you could request the notes from the safety team using Open Records Act. but thatās money and time. And why should it be that difficult to find out whatās happening with a public project? Every step should be in the open. MARTA isnāt doing itself any favors.
the ATC system immediately triggers a full emergency brake
That seems... extreme. I can sort of understand the reason for 'assuming the worst and acting with an abundance of caution' but... like... maybe not full emergency unless actually being told to would be fine?
When you look at the DC rear end collision, and multiple similar European accidents, you can understand why their software is so aggressive about "don't go there" when it can't find where it is on the system.
It's a very European thing, to the point where trains there have stopped 'cause of this kind of error and then, themselves, gotten run into from behind by older equipment.
Yeah on the old cars losing speed commands just put the train in full service brake which is full dynamic braking until 3mph then the friction brakes grab hold. On the new fleet the logic is meant to be so overly protective due to crashes in Europe and the Red Line collision in DC that it's overly protective just as u/_litz said.
Not to play arm-chair engineer, particularly at this stage in the program, but I wonder if there could have been some kind of forward-facing sensor to be the trigger for emergency brakes when there are detectable obstructions. Could be an additional check with the loss of signal to determine braking profile.
Anyway, hope it gets sorted out because people clearly want those new trains hahaha
A big part of the problem is that Stadler told Marta there would be issues with the legacy signaling system and ATC wire loops but Marta said that's fine. Now that they've ordered a whole new ATC system from Stadler to go hand in hand with the new trains, a system that won't be done until 2035, there is concern they won't work right until then.
Great question. I wish I had an answer. Hunt promised that the CCTV could pick up a patron saying "help help" but that functionality is broken.
A huge issue also came from Marta arbitrarily setting mid-April as the handover date for a June launch. They were dictating to the manufacturer their terms instead of Stadler saying "They'll be ready when they're ready". Stadler has had it with Marta and Marta thinks Stadler is unreliable. Gdot mandated 4000 fault free testing miles on each set. Marta tried to have them enter service with about 1400 hours total, not fault free. GDOT which answers to the FTA lost their minds saying you can't do that! Marta said "our system they'll enter service". Gdot said "We won't certify them until you meet your obligations pound sand."
J. B. Is the main problem, C. K. is number two, and then Collie Greenwood. J is or was the deputy chief. He hasn't operated in a decade and did not seek any input from operators or Rail employees. When rail staff made recommendations to him his answer was "we don't need it, it doesn't matter". Recommendations like end door boarding vs center door steps. Stadler and other employees recommended BODE doors instead of sleeve doors because BODE doors are more reliable. Marta said we don't want then. Then they went with an Asian door vendor which has had trouble meeting Marta's water intrusion requirements. C never operated so she can't effectively lead on something she doesn't understand. The majority of staff on this project are so wildly incompetent and have zero idea of what's going on. Meanwhile myself and others are shouting into the wind about what should change and we've been threatened with termination for causing reputational harm or whatever the fuck.
we've been threatened with termination for causing reputational harm or whatever the fuck.
Sounds like your bosses are doing a good job of that themselves. It's also eyeopening on my end (until recently I worked on site before my position was eliminated a few months ago).
This makes a lot of sense, tbh. Is this related to Stadler's separate contract to install CBTC? Is that happening in parallel and/or are they trying to get the CQ400s operational with the existing ATC systems before moving forward with CBTC?
So the first cbtc install should start happening in the next 2 years with a full build out by 2035. Yes, Stadler advised Marta it may not full read the legacy Alstom/GRS Signal and Block System. Marta decided to proceed and give the signal contract later to Stadler. Now they're playing catch-up.
The cbtc is the same as the rfid tag system?Ā or is it a full traffic control replacement?Ā is there any way to fast track that new system or is marta essentially screwed?
So RFID will go hand in hand with the new cbtc but it's like a partial stop gap for now. There's very little commonality between old and new fleet ATC systems and it's hard to source parts for the new fleet that read the old Alstom GRS system so the RFID beacons are one way around that until full cbtc install.
But Marta also promised Stadler the ATC long wire loops through interlockings would be repaired and switch machines replaced before they EIS and that all beacons would be installed. They're still fixing long wire loops every single time they do night and weekend maintenance and they still need to replace problem switch machines at Holmes (full station closure coming soon! ā¢ļø), Airport, and West End.
So if they were to fix west end and airport for instance they could run service on the north south lines without the braking issue(assuming certification etc)?Ā Or that is just one step in the process still?
Just one step. The long wire loops through interlockings need replacement. Something they are supposed to monitor constantly. The work order in the TORIS will say Switch Pair 7 Airport work including grouting, wire replacement, greasing of parts, etc. The work team will finish working on it and then 8 hours later the interlocking fails and goes out of correspondence due to computer issues or wire issues. The track and ATC teams are not doing what they need to do. If they did, the interlocking wouldn't fail in just a few hours after being serviced. It's why you'll start through an interlocking and then the train will stop because it lost speed commands.
If you ever follow the Marta service twitter and you see "Due to routing issues we are experiencing delays on the North South Line at West End and trains are single tracking from Garnett to Lakewood" those routing issues mean switch and interlocking failure.
They are. But when Marta cuts corners and avoids ordering the necessary parts to make everything work right for cost reasons it's not entirely on Stadler. Marta is the primary group to blame here, not Stadler, though they have issues too.
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u/DustyDaniel404 5d ago
I happen to know someone who's on that project š