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DPU & helpers.

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DPU & helpers.
Posted by SouthPenn on Tuesday, May 08, 2018 10:34 PM

What is the difference between radio controlled helpers and DPUs?

South Penn
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Posted by VOLKER LANDWEHR on Wednesday, May 09, 2018 5:21 AM

Radio controlled helpers are now called DPU.

If you use the term helper, a manned helper is meant nowadays.
Regards, Volker

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Posted by pajrr on Wednesday, May 09, 2018 10:40 AM

Normally, helpers are used for short term power on grades. DPUs stay with a train the whole way since they are part of the road power needed to move the train under normal conditions. If a train needs 3 locos to do a run, you can put 1 in front, one in the middle and one on the rear if you want. You have 3 locos, doesn't matter where you put them. Now if you need more power for a grade or mountains, you add manned helpers to the consist for the time needed.

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Posted by NWP SWP on Wednesday, May 09, 2018 10:47 AM

This recent thread might help.

http://cs.trains.com/mrr/f/13/t/269772.aspx

 

Steven

Crooner, Imagineer, High School Senior, living with Aspergers, and President of the NWP-SWP System.

Modeling the combined lines of the Southern Pacific, Western Pacific, and Northern Pacific after a fictional Depression Era merger forming the SouthWestern Pacific and NorthWestern Pacific Railroads. SP, WP, and NP operations remain independent but also operate alongside NWP and SWP equipment.

Hook'em Longhorns! 

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Posted by VOLKER LANDWEHR on Wednesday, May 09, 2018 3:35 PM

pajrr
You have 3 locos, doesn't matter where you put them. Now if you need more power for a grade or mountains, you add manned helpers to the consist for the time needed.

If the necessary tractive effort of the locomotives to pull a train exceeds the coupler strength you can't put all locomotives at the head end. Otherwise the coupler might break a coupler. Next step you put locomotives at the end as they are easier to add or to remove.

UP has a chapter about helper placement in its System Special Instruction.

Locomotive information starts on page 33, helper placement on page 46. What is missing is the TE requirement for the subdivisions.

Nowadays trains get even over mountains with just DPUs. What once were helper districts often only have DPUs now. Helpers were once the norm currently they are more the exception from the rule.
Regards, Volker

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