light rail train hits van

[trainman1980]

I just saw this clip on TruTV tonight.
http://www.youtube.com/watch?v=YqAIb7RL20k

 

[adurbin]

I didnt see it hit a van??????

 

[trainman1980]

I didnt see it hit a van??????

I fixed the link.I posted the wrong link by mistake.

 

[lmackattack]

ouch! the pole the van hit was the worst of it!

 

[UP2CSX]

I'm surprised how fast the LRV stopped. It looks like he clipping right along when he hit the van. I'm also surprised the LRV apparently stayed on the track.

 

[diburning]

LRVs are good at stopping because in most cases, they have three brakes, the pneumatic air brake, the physical brake that grips the wheel when it goes into emergency, and the track brakes (2 on each truck) which is used for hard braking such as a station stop at high speed or for emergency use. The track brake is a large springloaded slab of metal that is held up on the trucks when not deployed, and drops onto the track and creates friction when it is deployed.

On some of the older Boeing LRVs (when they were still running on the MBTA), sometimes the track brakes on one of the trucks had a failed spring (it's mechanically held up by two springs) and has half of the track brake dragging on the rail.

The lighter weight of the LRVs, their short train length, as well as having every truck brake at the same time also helps them stop quickly.

Same general idea with subway cars although they generally do not have track brakes.

http://www.youtube.com/watch?v=T6WG_qEHcGU

(this is a surveillance video from the MBTA of a drunk woman who fell off a platform and a train nearly hitting her)

 

[julienjj]

it's funny here our subway dont have steel wheel but truck tires instead, so braking isnt a real problem

 

[UP2CSX]

Braking with rubber tired transit/subway cars is just as big a problem as it is with steel wheels. It can actually be worse because the steel wheels will heat up and provide some additional friction for braking. Rubber tires don't add any braking power so they need additional electomagnetic braking connected to the steel flanges behind the rubber tires. The system generally works well but it depends on wood brake blocks lubricated with peanut oil for the the last 10km/h of stopping, which accounts the characteristic smell in the Montreal Metro station. The wood blocks have to be changed out out fairly frequently, since repeated stops form a glaze that makes the brakes useless. The biggest issue is that the whole system is not weatherporoof, so the entire Metro has to run underground.

 

[julienjj]

i did know for the peanut oiled wood, but i cant still understand why they didnt put disk brake like a car or a truck

 

[UP2CSX]

No way disk brakes have the stopping power in an emergency. The electomagnetic brakes use the steel flange against the steel rail to provide very fast and powerful braking power. They added the wood blocks for final braking because the electromagnetic brakes squeal so bad it would drive people in the station up a wall.

 

[diburning]

No way disk brakes have the stopping power in an emergency. The electomagnetic brakes use the steel flange against the steel rail to provide very fast and powerful braking power. They added the wood blocks for final braking because the electromagnetic brakes squeal so bad it would drive people in the station up a wall.

Amtrak's Amfleets use disk brakes. The disk is in the middle of the axle. They were designed that way so that the coaches would get fewer flat spots (for passenger comfort)

 

[MGWSY]

Amtrak's Amfleets use disk brakes. The disk is in the middle of the axle. They were designed that way so that the coaches would get fewer flat spots (for passenger comfort)

Actually Amfleets use a combination of disk and regular brakes.

 

[julienjj]

No way disk brakes have the stopping power in an emergency. The electomagnetic brakes use the steel flange against the steel rail to provide very fast and powerful braking power. They added the wood blocks for final braking because the electromagnetic brakes squeal so bad it would drive people in the station up a wall.

but there is no rail in this metro, there is 2 "trench" for the wheel and 2 flange
like a roller coaster made of wood to keep the wheel align
well in fact there is rail but its only for electric pickup.

 

[UP2CSX]

That rail is what's used for the electromagnetic braking. The power from rail drives the braking magnets that push the steel flange against the rail. The next time you're at the Metro, take a look behind the rubber tire and you'll see the steel flange. My brother was working for Honeywell at the time the Metro was being built and helped to design the braking system. The original plan was to use automotive style disk brakes until testing revealed they couldn't bring the train to an emergency stop fast enough and before the disks got overheated and fractured. It's a similar issue with the Amfleet cars. The disk brakes work well enough for a normal stop but you need the additional braking power against the steel wheel for an emergency stop.

 

[ChevelleSSguy]

It looks like the van driver didnt check his blind spot and just cut the train off much like you would check your blind spots when changing lanes on the freeway. I would think there would have had to be crossing lights flashing though.

 

[diburning]

Light rail crossings do not have flashing lights and gates.

 

[UP2CSX]

I know that intersection. The traffic light turns to flashing red in all four directions and there's a sign saying "Danger-Train Coming" that lights up at the same time. The guy in the van blew through the flashing red and obviously ignored the lighted sign. You can see the track that doesn't cross the intersection has curbs to keep vehicles out. There's only so much you can do when you mix LRV's, street running, and idiots to prevent this kind of accident.

 

[macjet]

I'm surprised how fast the LRV stopped. It looks like he clipping right along when he hit the van. I'm also surprised the LRV apparently stayed on the track.

We rode DART for the first time this weekend and I was VERY surprised at how fast that thing accelerated and decelerated.

 

[julienjj]

That rail is what's used for the electromagnetic braking. The power from rail drives the braking magnets that push the steel flange against the rail. The next time you're at the Metro, take a look behind the rubber tire and you'll see the steel flange. My brother was working for Honeywell at the time the Metro was being built and helped to design the braking system. The original plan was to use automotive style disk brakes until testing revealed they couldn't bring the train to an emergency stop fast enough and before the disks got overheated and fractured. It's a similar issue with the Amfleet cars. The disk brakes work well enough for a normal stop but you need the additional braking power against the steel wheel for an emergency stop.

3 things :

-I saw that the TGV use 4 disk brake per axle to brake, so disk are obviously strong enought to be used alone (if designed to)

-listen to this, its a funny things about our metro(its "play" a weird sound) :http://www.youtube.com/watch?v=fTwWzQSc0oI


-the car driver is an idiot, he endangered his life and the passenger one, just to save 10sec

 

[UP2CSX]

Julien, the TGV's use a lot more than disk brakes to stop, and the next generation trains will have to use a completely different braking system for safety and to reduce maintenance. There's a good article about it at http://www.railfaneurope.net/tgv/research.html.