Trailing head end unit as DPU master - why not?

[NS9710]

Why is it that the head end leading unit can only be used as a DPU master and not one of the trailing units on the head end, I mean the trail units on the head end are MU'd and responding the exact same as the locomotive on point, but yet in the slave position it doesn't matter if it's the first or second unit. I've done this railroad thing since 1986 and I never got a clear cut answer on this, can someone explain this to me?

 

[AK9R]

Doesn't the DPU master need to be configured and monitored by a human? If a trailing head end unit was used as the master, wouldn't someone have to be in the cab of the master?

 

[NS9710]

Well it would have to have the initial setup, but I would imagine that the trailing unit [master] would send a "Train Line Alarm" to the head end should something go wrong, Most of the guys I know don't even run the DPU screen constantly and just waits for the locomotive to alarm/alert them when it has an issue.

Doesn't the DPU master need to be configured and monitored by a human? If a trailing head end unit was used as the master, wouldn't someone have to be in the cab of the master?

 

[ComradeGlock]

I'm not a loco engineer (just loco), but if the lead unit is not the DPU master, how would the engineer control the DPU units separately from the lead unit(s)? Extreme example of cresting a grade: on a very long train, lead units might be at idle or in dynamic after the crest while DPU unit(s) still climbing the grade might be in Run 8.

 

[NS9710]

Very good point.
Forgot about that point

I'm not a loco engineer (just loco), but if the lead unit is not the DPU master, how would the engineer control the DPU units separately from the lead unit(s)? Extreme example of cresting a grade: on a very long train, lead units might be at idle or in dynamic after the crest while DPU unit(s) still climbing the grade might be in Run 8.

 

[burner50]

I'm not a loco engineer (just loco), but if the lead unit is not the DPU master, how would the engineer control the DPU units separately from the lead unit(s)? Extreme example of cresting a grade: on a very long train, lead units might be at idle or in dynamic after the crest while DPU unit(s) still climbing the grade might be in Run 8.

This is called "Putting up the fence", and may be necessary depending on the terrain. This is the reason why DPU is always on the head end. In addition, the DPU needs to be placed into "Set Out Mode" if the trainline is going to be broken to pick up or set out cars. Also, the engineer needs to be able to monitor the status of the DPU and ensure that it maintains communication to verify the integrity of the train and remain in compliance with EOT rules/regulations and ensure a complete brake pipe just like with an EOT.

 

[NS9710]

I’m familiar with that part, I just didn’t think of the advanced operations aspect before now

This is called "Putting up the fence", and may be necessary depending on the terrain. This is the reason why DPU is always on the head end. In addition, the DPU needs to be placed into "Set Out Mode" if the trainline is going to be broken to pick up or set out cars. Also, the engineer needs to be able to monitor the status of the DPU and ensure that it maintains communication to verify the integrity of the train and remain in compliance with EOT rules/regulations and ensure a complete brake pipe just like with an EOT.