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smallspy said:
The computer that failed was a dispatching computer, not a signalling one. So this failure could have just as easily happened on the B-D or Sheppard as it did on the YUS. As to why? They're looking into that.

The signalling system on the YUS is broken out into several firewalled parts, which is why when it fails only a smaller section of it goes down.

Dan
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So then how did the entire line go down?
 
Bordercollie said:
So then how did the entire line go down?
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I would imagine it didn't, but if a particularly large enough section freezes at rush hour, there's no slack for trains to move forward in the scheduled service level.

Yes, you could initiate procedures to have turn-backs and such, but this sounds like it was in the grey area of the decision matrix where you are told "it will be somewhere between 15 and 45 minutes," so you have to make the decision; do you implement complex, higher risk operating procedures to arrange for turn-backs and short turns, and also make a call for shuttle buses because it could be 45 minutes, or do you decide to hold everything and wait it out in case it's only 15 minutes? You have to decide on one or the other immediately. You have 30 seconds to make the call after receiving the information. They chose to hold and wait it out.
 
Jonny5 said:
I would imagine it didn't, but if a particularly large enough section freezes at rush hour, there's no slack for trains to move forward in the scheduled service level.

Yes, you could initiate procedures to have turn-backs and such, but this sounds like it was in the grey area of the decision matrix where you are told "it will be somewhere between 15 and 45 minutes," so you have to make the decision; do you implement complex, higher risk operating procedures to arrange for turn-backs and short turns, and also make a call for shuttle buses because it could be 45 minutes, or do you decide to hold everything and wait it out in case it's only 15 minutes? You have to decide on one or the other immediately. You have 30 seconds to make the call after receiving the information. They chose to hold and wait it out.
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A simple solution would be to if the delay exceeds X minutes they should initiate short turn protocol. Instead of running shuttle buses to get people down yonge st it may be smarter to help shuttle people east or west depending on where the issue is. Clearly it's a mismanagement issue more than anything. Asleep at the wheel basically.
 
Bordercollie said:
So then how did the entire line go down?
Click to expand...
Because it was a dispatching system, as I said. It dispatches all of the trains along the line, and the signal system ties into it to allow for permission according to the schedule.

Bordercollie said:
A simple solution would be to if the delay exceeds X minutes they should initiate short turn protocol. Instead of running shuttle buses to get people down yonge st it may be smarter to help shuttle people east or west depending on where the issue is. Clearly it's a mismanagement issue more than anything. Asleep at the wheel basically.
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This is already in place. But it wasn't applicable here.

Dan
 
allabootmatt said:
You've put your finger on something I have been wondering about. When it comes to transit, at least, what has the last 50 years of technological development actually gotten us? The Crosstown is apparently paralyzed by software issues and broader problems of systems integration. And yet the original Yonge and Bloor subways were built, delivered and run for decades with nothing more sophisticated than a slide rule. "Software" barely existed. Go back further, to the birth of the systems in Paris, London and New York, and it's an even bigger gulf.

OK, it's obviously good to have elevators and modern fire-suppression systems. But apart from a few safety-related changes, what are the real benefits of the current model, exactly? And if such benefits are real, but they mean every project takes 2-3x as long to build, and is then 2-3x like likelier to fail when some aspect of the tech goes down, what's the point?

I am increasingly of the view that public procurement, probably for more than just transit, needs to be re-oriented to prioritize systems that are simple, robust and above all deliverable.
Click to expand...

It's not the first time - remember back in 2015 when a really minor technical issue ended up bringing down the entire comms system:

toronto.citynews.ca

All subway service has resumed, TTC says

Subway service has resumed on all lines after earlier radio communication issues, the TTC said on Monday.
toronto.citynews.ca toronto.citynews.ca

AoD
 
smallspy said:
They are arguably too sensitive however. Early on, a pan drop was considered a major fault and required the car to be removed from service immediately. I guess that they've finally realised that there is no damage to the pantographs when this happens, and so the car (in most cases) can switch to the pole and have its pantograph inspected later.
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Isn't all the new wiring panto-only now instead of the pole-and-panto hybrid plan that had them adding ears to all the frogs? That throws a wrench into the "switch to the pole and inspect the panto later" backup plan...
 
KevinT said:
Isn't all the new wiring panto-only now instead of the pole-and-panto hybrid plan that had them adding ears to all the frogs? That throws a wrench into the "switch to the pole and inspect the panto later" backup plan...
Click to expand...
Yes, not quite all has been converted yet but in due course poles will simply not work (or only on the straight sections of overhead! (For pantos the wires are also not completely straight so that the contact point on the panto changes and it wears out all over and not in one spot. That too would probably confuse the poles!)
 
Not too sure where to put this, but after a service disruption this morning due to "emergency rail repairs" Kipling-bound Line 2 trains seem to have slowed down after leaving Warden once again.
 
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KevinT said:
Isn't all the new wiring panto-only now instead of the pole-and-panto hybrid plan that had them adding ears to all the frogs? That throws a wrench into the "switch to the pole and inspect the panto later" backup plan...
Click to expand...
A lot of it is, but not all of it yet.

That said, in an emergency, the pole can be (carefully) used on pan-only overhead with the help of someone following along, watching and guiding it. The shoe doesn't need to be on the overhead - the entire pole is conductive.

Dan
 
smallspy said:
That said, in an emergency, the pole can be (carefully) used on pan-only overhead with the help of someone following along, watching and guiding it.
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Huh?? That doesn't sound correct at all probably only necessary at switches and if the streetcar had to revers with the pole up otherwise the shoe would follow the wire
smallspy said:
The shoe doesn't need to be on the overhead - the entire pole is conductive.
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Not true at all the pole is non conductive the only part that is the piece of carbon in the shoe that makes contact with the wire, The pantographs also use carbon on the conductive suffice as well
 
EastYorkTTCFan said:
Huh?? That doesn't sound correct at all probably only necessary at switches and if the streetcar had to revers with the pole up otherwise the shoe would follow the wire

Not true at all the pole is non conductive the only part that is the piece of carbon in the shoe that makes contact with the wire, The pantographs also use carbon on the conductive suffice as well
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Not so sure about that.

Seen by me - one of the old CLRV streetcars became stopped with its pole under a section isolator, it was stuck - until another car came from the other direction. The operator of the other car used the rope to position the pole of the stuck car against the overhead cable outside of the section isolator, and the operator of the stuck car was able to move forward to the point where the pickup shoe would no longer be under the section isolator. It struck me at the time that the operator on the outside of the car had not positioned the shoe on the other wire, just the side of the pole in order to make the connection. So obviously, the pole was conductive at the point where he placed it against the overhead wire.
 
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EastYorkTTCFan said:
Huh?? That doesn't sound correct at all probably only necessary at switches and if the streetcar had to revers with the pole up otherwise the shoe would follow the wire

Not true at all the pole is non conductive the only part that is the piece of carbon in the shoe that makes contact with the wire, The pantographs also use carbon on the conductive suffice as well
Click to expand...
Check your information. Trolley bus poles are fibreglass, as you don't want to create a short by having a dewired pole touch both lines.

Streetcar poles are steel, and have been forever. That's why they bend and don't break when they fail.

Dan
 
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