dowlingm
Senior Member
I wish 4401 could at least be used for panto testing and parades.
As for 4466
As for 4466
as long as its pole was down this time
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nfitz
Superstar
It's done both, I believe. Here it is with the pantograph up on Queen Street East, westbound, coming off the bridge over the Don.
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Maltesefalcon
New Member
I think the power supply to the TTC streetcars is 600V DC.
What would happen to the system if a high tension wire line landed on the tracks?
I think they are 18000 volts or something like that.
What would happen to the system if a high tension wire line landed on the tracks?
I think they are 18000 volts or something like that.
TransitBart
Senior Member
You would have a short circuit. Same as at home, but on a bigger scale. The tracks are a very effective ground. The arcing would continue until the breakers kicked in.
M II A II R II K
Senior Member
Soon a 4500 party will be thrown when it’s delivered.
Allandale25
Senior Member
^ I'm in!
thettctransitfanatic
Senior Member
I would go to that !
robmausser
Senior Member
Maltesefalcon
New Member
Hard to tell but that looks like a TTC power line which as I said before is 600v
A high tension wire on the tracks would still ground out as mentioned above. I am just wondering if an 18ooo volt line on the tracks would also send a massive surge through the vehicle and into tbe positive side of the power supply before the breaker kicked out?
A high tension wire on the tracks would still ground out as mentioned above. I am just wondering if an 18ooo volt line on the tracks would also send a massive surge through the vehicle and into tbe positive side of the power supply before the breaker kicked out?
lenaitch
Senior Member
It might. I would imagine the electronic components are well protected but still sensitive enough that they'd have to get the parts manual out. I don't know how the presence of AC into a DC circuit would react but the voltage differential is significant. The short is going to look for ground any way it can and the least resistive path would be directly to earth but some might want to try to take the scenic route. The over-current protection (both in terms of current and time) on distribution lines is set quite high so that spurious faults like branches and critters can be self-clearing.
KevinT
Active Member
Anything falling from above will hit the contact wire for the poles/pantographs before hitting the tracks, and there will be surge arresters connected between the overhead system and ground sprinkled liberally throughout the system.
Waterloo Region's new Ion light rail system is fed at 750 volts DC, and as part of the utility relocations done before track construction all of the high voltage lines (typically 13.8 kilovolt AC) that crossed the route were buried. You'll see a pole on one side of the tracks with wires leading down into the ground, then they'll run back up a pole on the other side to continue on. The only exception to this was the 250 kilovolt tower line that links the region to Orangeville, which crosses the Ion line once at Weber St in Waterloo and again at King St. between Conestoga Mall and Northfield Dr. in Waterloo. While I'm sure the arresters would trip Hydro's breakers and that the vehicle design would no doubt keep passengers safe if that line ever came down, there would probably be months of down time for system repairs and re-certification after a line crossing event like that.
Ion has surge arresters that look like the ones on page 16 of this Siemens brochure mounted at the tops of the poles every city block or two. They connect directly to the messenger (top) wires of Ion's catenary system and a ground wire that runs down the pole. I don't know if the ones the TTC uses in Toronto are the same or something else entirely, but I'm certain they'd have something similar.
W. K. Lis
Superstar
I hope they tested for such an occurrence at the factory. Don't want to see a "test" like that on the streets anywhere.
steveintoronto
Superstar
I was there shortly after it occurred. lol...I guess being an electronic tech, it's easy for me to be in wonderment at peoples reaction to 600V arcing.
Just think welding, and with a hell of a lot lot less ampacity available. It was the overhead line, the catenary, and an errant pole after the switch where Dundas meets Roncy dragged it down and snapped it.
And, don't think for a moment that the breakers would kick *out* (someone got it backwards in an earlier post, stating "in") with that degree of arcing. Arcing in itself is often a load within line ratings. Thus the need for AFCIs in domestic wiring now. https://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter
It would take a dead short to blow the breakers. Yes there would be sparks, but not arcing per-se.
Btw: The vehicle was pushed from there by the following streetcar, it was disabled by the event or something preceding it.
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Richard White
Senior Member
A couple years ago I was leaving work when a school bus careened over the Front Street bridge at Spadina heading south. The brakes failed and it took out a pole or two before going through the streetcar island.
The wires did some down with the poles and clipped me on the side of the head. Luckily for me the power must have cut itself out before making contact with the side of my head. Heavy gauge silver wire hurts every time.
pstogios
Senior Member
Holy crap!! That’s quite the close call and quite a story to tell. Glad you’re ok!!