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Train losing air and going into emergency

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Train losing air and going into emergency
Posted by Perry Babin on Saturday, April 29, 2023 6:33 PM

When a train goes into emergency (like when it breaks an air connection), does the locomotive automatically drop to notch 0 and apply its brakes or does the engineer have to make the decision to do that (or whatever is appropriate)?

Are the locomotive brakes engaged on loss of air pressure?

Does this forum have a spellcheck?

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Posted by BaltACD on Saturday, April 29, 2023 8:05 PM

The forum does not have spell check, however, if you have Window 10 or higher there is a option you can use to engage it.

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Posted by adkrr64 on Saturday, April 29, 2023 8:33 PM

Perry Babin
When a train goes into emergency (like when it breaks an air connection), does the locomotive automatically drop to notch 0 and apply its brakes or does the engineer have to make the decision to do that (or whatever is appropriate)?

Are the locomotive brakes engaged on loss of air pressure?

Does this forum have a spellcheck?

Yes, when the train goes into emergency, it triggers a device called the Power Control Switch (PCS). The PCS cuts power to the locomotive, effectively putting it in idle. Each locomotive in the consist will react the same, provided the units are properly configured for MU operation.

As for brakes, the loco brakes will apply if the engineer does nothing, just as they would during an automatic brake application. However, the engineer can bail off the loco brakes, and it is often instructed to do so by the train handling rules for the railroad. In the event of a train separation, this helps to avoid having the rear portion of the train run into the leading portion.

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Posted by jeffhergert on Saturday, April 29, 2023 9:05 PM

Most of our road engines have a 20 second delay before the PCS opens up.  Also to try to keep the rear end from running into the head end.

Jeff 

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Posted by blue streak 1 on Sunday, April 30, 2023 1:30 AM

jeffhergert

Most of our road engines have a 20 second delay before the PCS opens up.  Also to try to keep the rear end from running into the head end.

Jeff 

 

One way to describe streach braking?  Is it only the leading loco that the PCS operates or  are all locos independent?  Imagine DPUs same as previous sentence.

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Posted by Perry Babin on Sunday, April 30, 2023 1:49 AM

I've seen the PCS referred to as the power control switch and the pneumatic control switch and the power cut-off switch. Are all equally acceptable?

Is the preferred term associated with one railroad line or maybe to a locomotive manufacturer?

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Posted by jeffhergert on Monday, May 1, 2023 11:17 AM

blue streak 1

 

 
jeffhergert

Most of our road engines have a 20 second delay before the PCS opens up.  Also to try to keep the rear end from running into the head end.

Jeff 

 

 

One way to describe streach braking?  Is it only the leading loco that the PCS operates or  are all locos independent?  Imagine DPUs same as previous sentence.

 

It's not really stretch braking.  I suppose a very broad interpretation could include it as stretch braking.

The lead engine's PCS controls the entire lead consist.  It's not unusual to see a trailing unit with the PCS being open, often from a start up penalty.  As long as it's set up to trail it doesn't affect anything.

I don't know it the 20 second delay happens on entrained DPs.  Off hand, I would think the DP software would shut it down immediately.  So as not to push that section of the train should it me behind the break.

Regarding what PCS means, all three are acceptable.  It seems in older manuals, Pneumatic Control Switch seemed to be preferred.  Now Power Cut Off switch seems more in vogue.  Power Control Switch seems to be becoming used, at least on forums.  It probably comes down to generational and regional preferrences.  Most of the official manuals and rules just use "PCS", most likely because everyone with a little time in know what's being talked about.

Jeff

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Posted by tree68 on Monday, May 1, 2023 1:20 PM

jeffhergert
Most of the official manuals and rules just use "PCS", most likely because everyone with a little time in know what's being talked about.

Any locomotive I've been in simply labelled the indicator lamp on the console "PCS."

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