Western Railroad Discussion > Multiple Engines Used

I'm just a lay person but seeing so many trains passing thru Truckee Ca, I'd like to know when I see many times that there are one or two engines in the middle of the train plus one or more on the rear how there speed control matches all the engines together.  
Thanks much -
GG

remote control

 Well, the simple explanation is that the engineer has the ability to control the "extra " engines from up front, and they call it "distributed power."  I'm sure someone on TO will give a more detailed explanation.

Yes, the mid train DPU or rear DPU or both are controlled from the lead engine via remote control essentially, whatever the engineer does on the lead locomotive is applied to the DPUs as well, the DPUs can also be controlled independently

Posted from Android

In the case of the coal train derailment east of Denver this morning, does the rear DPU shut down when an air line breaks or when the engineer bails off the power?

I believe locomotives automatically go to idle as soon as the air line breaks (or the engineer dumps the air).

czephyr17 Wrote:
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> I believe locomotives automatically go to idle as
> soon as the air line breaks (or the
> engineer dumps the air).

You would be correct.

Posted from Mobile Safari

And in case you did not know it, DPU stands for Distributed Power Unit. 

Unless they are set up to keep doing what they were doing for 30 seconds after the emergency application. Conrail sets theirs up like that. UP has some ACes set up that way as well. One was pushing 844 flat one day......
Santa Fe has dynamic brake holding feature in emergency.

Posted from Android

SD45X Wrote:
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> Unless they are set up to keep doing what they
> were doing for 30 seconds after the emergency
> application. Conrail sets theirs up like that. UP
> has some ACes set up that way as well. One was
> pushing 844 flat one day......
> Santa Fe has dynamic brake holding feature in
> emergency.
>
> Posted from Android

Seems counterproductive to keep pushing after the emergency application. What's the rational?

you can tell by the bunching of cars in the denver derailment that things get ugly with dpu's  makes things a little worse, even an immediATE SHUT DOWN ISN'T IMMEDIATE REALLY, KINDA GRaDUAL

They're learning, it used to be a lot longer than 30 seconds, at least on a comm break which
of course could occur if the master unit is disabled ie wrecked.

Out

callum_out Wrote:
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> They're learning, it used to be a lot longer than
> 30 seconds, at least on a comm break which
> of course could occur if the master unit is
> disabled ie wrecked.
>
> Out

Now I understand. The 30 second delay was used in the event line-of-sight radio communications were lost (going around a bend in a rocky area, or for some other reason).