[dowlingm]

The DC metro's main problem is coverage within the city. It functions more like a suburban commuter line in that stretches way out into communities in VA and MD (all of which pay into the cost, fortunately) but it doesn't make much sense for most trips within the centre and the headways are pretty long late at night. And if you can't use the metro in town to get where you want to go, there are buses, but again, big gaps in coverage plus service is affected by horrible traffic congestion at times. The H/Benning Streetcar at least covers a gap in transit service in the area, runs mostly in its own ROW and connects to a major transit hub.

I was thinking more this: https://www.washingtonpost.com/loca...e4cae6-6eca-11e5-aa5b-f78a98956699_story.html

 

[the lemur]

I was thinking more this: https://www.washingtonpost.com/loca...e4cae6-6eca-11e5-aa5b-f78a98956699_story.html

Oh, I see. It does make sense to put WMATA safety under federal oversight, though, since it serves two states and the District. I don't get the impression that the Metro's safety issues are catastrophic but it's probably too much for the District alone to deal with.

 

[Duck]

4406 on the 510.

 

[EastYorkTTCFan]

4406 on the 510.

View attachment 68499

it actually looks pretty good in black and white

 

[W. K. Lis]

Toronto did not order PRIMOVE for its new streetcars. The penny-pinchers are doing the worst. With PRIMOVE the new (at least) streetcars would have been able to move through the power-out areas. See link.

 

[the lemur]

Flexities on the 510 using Bathurst this past weekend.

 

[EastYorkTTCFan]

Toronto did not order PRIMOVE for its new streetcars. The penny-pinchers are doing the worst. With PRIMOVE the new (at least) streetcars would have been able to move through the power-out areas. See link.

I wouldn't say penny pinching at all. This was freak thing that happened it's not something that could be predicted. Also there is no way for them to get around the existing cars that are stopped in front of them even if they did have an alternate power source. It would be like saying thath every house built in the city of Toronto should have a backup generator installed in it.

 

[cplchanb]

I wouldn't say penny pinching at all. This was freak thing that happened it's not something that could be predicted. Also there is no way for them to get around the existing cars that are stopped in front of them even if they did have an alternate power source. It would be like saying thath every house built in the city of Toronto should have a backup generator installed in it.

What they failed to do whether its Primove or not was to have any backup system in place. I find it disappointing that not only do they not have that but they also tied it to the subway power as well, and look what happened.
The fire killed 2 birds with 1 stone.

And in this case...yes every TTC house should have a generator installed since its so critical to the functioning of the city

 

[EastYorkTTCFan]

What they failed to do whether its Primove or not was to have any backup system in place. I find it disappointing that not only do they not have that but they also tied it to the subway power as well, and look what happened.
The fire killed 2 birds with 1 stone.

again it's not something they planned to do. Both are counted because they both use the same amount of power. It's like I said before it was freek thing that happened. It sucks when stuff like this happens but what happens if the backup fails or gets damaged as well.

 

[cplchanb]

again it's not something they planned to do. Both are counted because they both use the same amount of power. It's like I said before it was freek thing that happened. It sucks when stuff like this happens but what happens if the backup fails or gets damaged as well.

ok now youre going to what if a what if....critical infrastructure needs at least 1 level of backup no matter how small the chance of failure is because its never 0% especially if the whole streetcar network is tied to 1 source (correct me if im wrong). At least they split the power for the subway. The downtown core was almost paralysed this morning

 

[Napoleon]

again it's not something they planned to do. Both are counted because they both use the same amount of power. It's like I said before it was freek thing that happened. It sucks when stuff like this happens but what happens if the backup fails or gets damaged as well.

Fukushima is what happens. It's when you have a common-cause failure for your backup systems. This gets underestimated in probabilistic risk assessment (something I'm sure the TTC doesn't do). They assume they have 3 backup generators each with a 1 in 1,000 chance of failure, assume they're independent, and then just multiply the probabilities. Oh look, we have a 1 in a billion chance of failure. However, if a common cause failure, design flaw, fire, or say earthquake/tsunami knocks out all 3, the independence assumption is out the window.

 

[dowlingm]

Toronto did not order PRIMOVE for its new streetcars. The penny-pinchers are doing the worst. With PRIMOVE the new (at least) streetcars would have been able to move through the power-out areas. See link.

I find that very unlikely. Primove induction would have been as dead as the overhead with the traction grid down, and I doubt Mitrac batteries would have been enough to bridge a fully loaded Flexity at AM peak across the gap.

I am curious though as to whether 501/504 could have gotten as far as Cherry and turned back there vs Broadview if that section was operational.

 

[cplchanb]

Fukushima is what happens. It's when you have a common-cause failure for your backup systems. This gets underestimated in probabilistic risk assessment (something I'm sure the TTC doesn't do). They assume they have 3 backup generators each with a 1 in 1,000 chance of failure, assume they're independent, and then just multiply the probabilities. Oh look, we have a 1 in a billion chance of failure. However, if a common cause failure, design flaw, fire, or say earthquake/tsunami knocks out all 3, the independence assumption is out the window.

I dont think that any backup can prevent failure for an earthquake or tsunami since youll need to have it 100km away at least to prevent a common cause failure for that. However for a fire, its easy. Have your backups separated from your primary.

 

[cplchanb]

I find that very unlikely. Primove induction would have been as dead as the overhead with the traction grid down, and I doubt Mitrac batteries would have been enough to bridge a fully loaded Flexity at AM peak across the gap.

I am curious though as to whether 501/504 could have gotten as far as Cherry and turned back there vs Broadview if that section was operational.

at least it wouldve given them enough power to pull into the terminals instead of stopping dead in the middle of the streets. what if one of them died while in the middle of the intersection.....

 

[crs1026]

Primove is not a particularly energy efficient system.

As for backup - the entire downtown hydro supply has less than perfect backup, by today's standards. TTC is no better or worse off in this regard.

Hopefully this incident does give TTC a bit of political leverage. Budgets, after all, are what makes the difference. City Council is the weak link here.

- Paul