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Enviro 500

Transit in Vancouver: Questions and Answers

516 posts in this topic

Don't take my word for it, but I'm pretty sure that this is the sound of the air reservoirs (compressed air tanks) being loaded with air. I took an air brake course in February and the equipment we had to work with made lots of interesting noises when the air was being loaded; I'm very confident that this is one of them. For some reason, this sound seems to occur almost exclusively in mild to hot weather, so I would think that it's safe to attribute this sound to humidity at the least.

Pretty sure you're right as you're even taking an air brake class but I guess it makes sense, since I would only hear this during the hot days and not in the middle of winter.

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Pretty sure you're right as you're even taking an air brake class but I guess it makes sense, since I would only hear this during the hot days and not in the middle of winter.

Taking a two-day course doesn't make me an expert, but thank you for your willingness to consider my theory. :P I may be even further off-base with this second perspective, but another possibility I was just thinking of is that the air reservoirs have accumulated too much water. Air brake systems are designed to limit the amount of moisture that reaches the reservoirs, but a little bit of water and dust is always able to pass through; I could see how humid weather would result in more of this type of contamination in an air brake system (it's suggested that reservoirs be drained daily, but who knows how often CMBC does this on their buses). I don't know what water sounds like in a compressed air tank, but maybe this is it(?).

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Taking a two-day course doesn't make me an expert, but thank you for your willingness to consider my theory. :P I may be even further off-base with this second perspective, but another possibility I was just thinking of is that the air reservoirs have accumulated too much water. Air brake systems are designed to limit the amount of moisture that reaches the reservoirs, but a little bit of water and dust is always able to pass through; I could see how humid weather would result in more of this type of contamination in an air brake system (it's suggested that reservoirs be drained daily, but who knows how often CMBC does this on their buses). I don't know what water sounds like in a compressed air tank, but maybe this is it(?).

Well it's better than not taking it, I thought it was just some loose nuts n bolts. I'm learning something new, where are the reservoirs in the brake system ? Also I doubt Translink would care about that, as long as the bus is running they could careless.

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Taking a two-day course doesn't make me an expert, but thank you for your willingness to consider my theory. :P I may be even further off-base with this second perspective, but another possibility I was just thinking of is that the air reservoirs have accumulated too much water. Air brake systems are designed to limit the amount of moisture that reaches the reservoirs, but a little bit of water and dust is always able to pass through; I could see how humid weather would result in more of this type of contamination in an air brake system (it's suggested that reservoirs be drained daily, but who knows how often CMBC does this on their buses). I don't know what water sounds like in a compressed air tank, but maybe this is it(?).

You're correct on all fronts. I "think" you're supposed to clear it once a day, every day. Water escaping an air tank sounds just like Ninja's video, the pitch depends on the size of the air tank. Its why its louder on a D40LF, then it is on a D60LF. Also, NovaBuses suffer from the same issue the only difference is the fact that its hidden in the engine compartment. Directly behind the center seat at the very back. On New Flyer buses, its mounted directly behind the last curb side seat on the right hand corner of the bus.

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On the New Flyers I think there is a small compartment door that is labelled Air Tank.

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Well it's better than not taking it, I thought it was just some loose nuts n bolts. I'm learning something new, where are the reservoirs in the brake system ? Also I doubt Translink would care about that, as long as the bus is running they could careless.

You're correct on all fronts. I "think" you're supposed to clear it once a day, every day. Water escaping an air tank sounds just like Ninja's video, the pitch depends on the size of the air tank. Its why its louder on a D40LF, then it is on a D60LF. Also, NovaBuses suffer from the same issue the only difference is the fact that its hidden in the engine compartment. Directly behind the center seat at the very back. On New Flyer buses, its mounted directly behind the last curb side seat on the right hand corner of the bus.

Kafi: CMBC definitely drains the tanks on their buses; they would cease to work it this duty was neglected and such inaction would likely cause a lot of costly damage if the contamination were to spread beyond the reservoir (note that it's not just water in there, the water mixes with other contaminants such as dust to create sludge). My question pertains to how often the tanks are drained. I've seen buses getting serviced overnight on numerous occasions and I have never seen the service persons tend to the tanks, which of course does not mean it doesn't happen, but rather that it probably isn't part of their overnight routine.

Bryan: Cool, glad we agree. Just to be clear and specific (since Kafi asked), the tanks are located below the ceiling, namely behind the ad-racks.

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Kafi: CMBC definitely drains the tanks on their buses; they would cease to work it this duty was neglected and such inaction would likely cause a lot of costly damage if the contamination were to spread beyond the reservoir (note that it's not just water in there, the water mixes with other contaminants such as dust to create sludge). My question pertains to how often the tanks are drained. I've seen buses getting serviced overnight on numerous occasions and I have never seen the service persons tend to the tanks, which of course does not mean it doesn't happen, but rather that it probably isn't part of their overnight routine.

Bryan: Cool, glad we agree. Just to be clear and specific (since Kafi asked), the tanks are located below the ceiling, namely behind the ad-racks.

I see your point now, these tanks have to be drained or else stuff will build up in there and cause mechanical issues. Maybe they drain the tanks once every few days ?

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I imagine each bus has a service log so things are done on a consistent basis.

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I don't know when the air tanks are drained completely by the valve from the tank itself, but a full airbrake test cycle is done everyday on every bus before it leaves the yard which includes applying the service brake until the reservoir is completely drained. Obviously if the bus is in for maintenance or not booked out, the air test isn't done. Also, the air tanks will drain on thier own if sitting for a long period of time, I think it's an automatic purge or something like that.

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I was at Braid Stn today and spotted P7431 with it's destination sign reading " DDR VEHICLE ".

What does that mean.

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I was at Braid Stn today and spotted P7431 with it's destination sign reading " DDR VEHICLE ".

What does that mean.

Designated Disaster Response Vehicle.

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Designated Disaster Response Vehicle.

Thanks, so that means during some kind of disaster people can board that bus ?

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Thanks, so that means during some kind of disaster people can board that bus ?

Yes, they can be used for a variety of purposes (e.g. provide shelter, transport people to safety, be used to set up a triage area on board, et cetera).

technically yes but also means Dance Dance Revolution Vehicle.

Good to know. :P

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Yes, they can be used for a variety of purposes (e.g. provide shelter, transport people to safety, be used to set up a triage area on board, et cetera).

I see, thanks.

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I've noticed that some D60LF's have this and what is it ?

8ZVRP2k.jpg?2

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hmm... I'm not 100% accurate but back before the Canada Line opened, all buses (R8057-R8084) are equipped with a GPS system and stop request announcement. for the 98 B-Line route, a first in Translink's history.

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hmm... I'm not 100% accurate but back before the Canada Line opened, all buses (R8057-R8084) are equipped with a GPS system and stop request announcement. for the 98 B-Line route, a first in Translink's history.

I am doubtful. I believe that the computer for this was located in the same place then as it is today, behind the operator. I also believe that the object in question is a transponder to keep traffic lights green until the bus has made it through (but I am not completely sure).

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I am doubtful. I believe that the computer for this was located in the same place then as it is today, behind the operator. I also believe that the object in question is a transponder to keep traffic lights green until the bus has made it through (but I am not completely sure).

It could be since we did go through a lot of green lights and rarely stopped at red lights along 41st Ave.

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Sorry again, but with the skytrain tracks, which track is the one that will electrocute you ?

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Sorry again, but with the skytrain tracks, which track is the one that will electrocute you ?

The power rails are the two strips mounted on the side of the guideway.

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The power rails are the two strips mounted on the side of the guideway.

So those are the rails that will kill you ? Then whats that metal one in between the tracks.

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Then whats that metal one in between the tracks.

I thought that metal 'wire' in the center (between the rails) was for communication.

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