Short turns and brake checks

Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

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Tallguy
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Short turns and brake checks

Post by Tallguy » Wed Sep 25, 2019 2:15 pm

So, I know that any passenger train changing directions at a terminal must test the brakes. Does a short turn require the same test? How about a non revenue turn, such as at SS, going out to Southhampton?

MBTA3247
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Re: Short turns and brake checks

Post by MBTA3247 » Wed Sep 25, 2019 4:06 pm

A brake test is required anytime you change which cab you're operating from, to verify that the brake stand at that end is working.
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Tallguy
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Re: Short turns and brake checks

Post by Tallguy » Sat Sep 28, 2019 3:48 pm

Thanks

CRail
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Re: Short turns and brake checks

Post by CRail » Sun Sep 29, 2019 11:55 pm

The brake test is to make sure the brake pipe pressure corresponds with what the automatic brake valve does at the other end. If the rear-most brake cylinder doesn't respond to the brake pipe pressure reduction from the control stand, the test fails and the train can't move until the cause is rectified and a successful test takes place. Every train in North America undergoes this test any time there's any change whether it be the operating stand or equipment added or removed to/from the consist, it is not limited to passenger trains.
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BandA
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Re: Short turns and brake checks

Post by BandA » Mon Sep 30, 2019 12:34 am

Do trolleys & subway cars also require the same full brake tests? Trucks probably have a similar requirement. What do they do in other countries?

CRail
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Re: Short turns and brake checks

Post by CRail » Mon Sep 30, 2019 6:58 pm

Multiple unit vehicles do not utilize the brake pipe to charge and control the brakes. While they do have a brake pipe to initiate an emergency application especially if the train splits, normal applications are an MU feature (an electric signal in the coupler tells each car what to do and each car does it itself). Railroad equipment that doesn’t run Multiple Unit (control cars don’t count since they are just remote controls and do not respond to their own throttles) rely solely on the pipe that runs end to end to charge and control brake applications. So it’s important to make sure the brake pipe is intact and functioning from end to end.
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Tallguy
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Re: Short turns and brake checks

Post by Tallguy » Tue Oct 01, 2019 6:53 am

So, multiple units don't need a brake test when they reverse directions?

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BandA
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Re: Short turns and brake checks

Post by BandA » Tue Oct 01, 2019 10:19 pm

Just make coaches that are non-powered MUs then, with those MU electrically-coupled brakes. QED.

CRail
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Re: Short turns and brake checks

Post by CRail » Wed Oct 02, 2019 4:03 am

Tallguy wrote:
Tue Oct 01, 2019 6:53 am
So, multiple units don't need a brake test when they reverse directions?
If referring to railroad MU equipment that still utilizes a "train air" system, then yes, they do. If referring to "straight air" equipment such as LRVs and subway cars, then no, they don't.
BandA wrote:Just make coaches that are non-powered MUs then, with those MU electrically-coupled brakes.
Why would someone with such a profound concern of fiscal responsibility want to reinvent the wheel to develop a non-existent technology and convert existing equipment to use it at tremendous capital cost just to avoid a 15 second test at the beginning of a trip?
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Tallguy
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Re: Short turns and brake checks

Post by Tallguy » Thu Oct 03, 2019 6:06 am

Because the need for brake tests that take 10 or more min to perform according to the MBTA on a route that is only 20 min each way.

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BandA
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Re: Short turns and brake checks

Post by BandA » Thu Oct 03, 2019 7:47 pm

I was under the impression from what I read in these forums that a brake test took about 10 minutes, clogging up platforms at South & North stations.

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Re: Short turns and brake checks

Post by nomis » Sat Oct 05, 2019 8:19 am

The approximate 10 minutes is more about: passenger movement, crew positioning, and schedule recovery & padding, than the actual time to perform the appropriate brake test.
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CRail
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Re: Short turns and brake checks

Post by CRail » Sat Oct 05, 2019 12:30 pm

Tallguy wrote:
Thu Oct 03, 2019 6:06 am
Because the need for brake tests that take 10 or more min to perform according to the MBTA on a route that is only 20 min each way.
Cite your source please. Even if that were true, it's a federal requirement for all railroad equipment. It is not a problem that needs solving.
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BandA
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Re: Short turns and brake checks

Post by BandA » Sat Oct 05, 2019 2:02 pm

My personal automobile does a brake self-test in 5 seconds. Is there any rail equipment using hydraulic brakes? Of course hydraulic fluid is another source of ground water pollution.

CRail
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Re: Short turns and brake checks

Post by CRail » Sat Oct 05, 2019 4:15 pm

Your automobile is not a train, nor is it comparable to one. The poster's question has been answered and I think the discussion is exhausted.
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