Dumping the air- sounds at a terminal station

[bikkuri bahn]

Kintetsu rolling stock is well known among fans for having a vigorous dumping of air at full stop when arriving at terminal stations- even more recent stock have their air dumped. Apparently the old system is kept for compatibility as much mixing of old/new stock occurs in services. Most modern rolling stock have brake systems that don't emit such a vigorous sound.

 

*above mainly at Kintetsu Nagoya Sta, and some scenes at Uehonmachi Sta.

 

In the Kanto region, Tobu's 8000 series is known for dumping the air (scene at Kashiwa Sta.):

[katoftw]

Not just louder than normal due to enclosed unground/basement style stations?

[bikkuri bahn]

No there actually Is a difference. Take these scenes at Shinkaichi Sta. on the Kobe Dentetsu. First, an older type, the 1100 series, with electro pneumatic brakes, note the characteristic "pshaa" sound of the air being dumped:

 

The newest Kobe Dentetsu type, the 6000 series, with electric commanding brake, silence after full stop:

[JR 500系]

Isnt that the normal for brakes? I mean, air release from the brakes?

 

We hear that from heavy vehicles too, like trucks:

 

[Jace]

Isnt that the normal for brakes? I mean, air release from the brakes?

 

 

Some trains are louder than others. Here in New York, newer trains like the R160s dump louder than older equipment. Someone who lives close to last elevated station on the Astoria line complained enough about the R160 noise that the MTA installed a small muffler on the cars. 

[miyakoji]

JR rolling stock (most of it, anyway, from the last few decades) makes a whirring sound when the air is released.  I've always imagined that this is some kind of little turbine serving as a muffler.  Unforutnately I'm having some trouble finding an example on youtube.

[bikkuri bahn]

It is hard to find good examples, one problem is the videos tend to cut off right when the train stops and before the brakes are put in emergency (full application), which is when the air is released.

[marknewton]

First, an older type, the 1100 series, with electro pneumatic brakes, note the characteristic "pshaa" sound of the air being dumped...The newest Kobe Dentetsu type, the 6000 series, with electric commanding brake, silence after full stop

I'm a bit confused about this. What's the difference between EP brake and electric commanding brake? I'm very familiar with Westcode EP brake because all the trains I run are fitted with it, but I'm not up to speed on what modern Japanese EMUs are fitted with. And in the second video, does the video actually show the moment when the driver cut out to change ends?

 

Cheers,

 

Mark.

[marknewton]

JR rolling stock (most of it, anyway, from the last few decades) makes a whirring sound when the air is released.  I've always imagined that this is some kind of little turbine serving as a muffler.

I doubt that it's a turbine. Some of our trains have a choke on the exhaust from the brake valve that makes a whirring sound when you blow the brake pipe down to zero when changing ends.

 

Cheers,

 

Mark.

[kvp]

There are various air brake configurations:

-single pipe

-dual brake/charge pipes

-electrically assisted dual pipe (aka. EP)

-fully electrical with no pipes between cars and self contained brake groups (aka. EC or software based failsafe)

 

The latter means you can't empty the trainline as there is none. The board system in each unit decides upon reception of a brake command what to do. Total signal loss usually triggers an emergency brake application, but if the train is stationary, it could just decide to respond to a full brake command with activating the parking brakes. Older EP sets had the parking brakes connected to the emergency release to add extra power on emergencies and to prevent a post accident/parking rolloff when the tanks get depleted. The closest to the modern electric command operation in old times were the all electric PCC-s.

 

ps: A single compressor failiure on a non through piped unit could lead to the loss of a married motor pair and its connected trailers, so a through charge pipe is often left with emergency braking on pressure loss, but this failsafe is not generally in use and only binary in operation. Some drawbar coupled sets may leave a few middle trailers unbraked apart from the parking brakes which could be dangerous if the train separates at more than one point.

[miyakoji]

I doubt that it's a turbine. Some of our trains have a choke on the exhaust from the brake valve that makes a whirring sound when you blow the brake pipe down to zero when changing ends.

 

Cheers,

 

Mark.

 

Yeah, I don't really think it is, but it seems like the pitch goes up a bit then slowly goes down as the sound trails off entirely, I was thinking what might sound like that if air were released against it.  I finally found a decent example, right at 0:01:

 

 

 

And now come to think of it, this is releasing the brake, not applying in full

Edited March 18, 2016 by miyakoji

[trainsforever8]

Yeah, I don't really think it is, but it seems like the pitch goes up a bit then slowly goes down as the sound trails off entirely, I was thinking what might sound like that if air were released against it.  I finally found a decent example, right at 0:01:

 

 

 

And now come to think of it, this is releasing the brake, not applying in full

 

Our MR-73 trains in Montreal also make this sound when the break is released!