| Home | Open Account | Help | 342 users online |
|
Member Login
Discussion
Media SharingHostingLibrarySite Info |
Western Railroad Discussion > DPU questionDate: 09/01/15 08:26 DPU question Author: boesrailfan Does the use of dpu's allow fewer locomotives to be used on a train, or does it just make more efficient use (acceleration, braking, etc) of the the same number that would normally be required to move a train? Thx.
Date: 09/01/15 08:35 Re: DPU question Author: Coalca Generally it allows the train to proceed with one less unit. A train requiring 4x0 before can usually run 2x1. (2 in front, one dpu).
With the DPU pushing on the rear, a significant amount of train-line flange drag is eliminated. It also eliminates Much of the weight on the front drawbars. Airing the train up from both ends is also advantageous. Edited 1 time(s). Last edit at 09/01/15 08:51 by Coalca. Date: 09/01/15 09:25 Re: DPU question Author: cascadehogger Depends on territory. On our hill over the cascade line, it boils down to tons per powered axle. What may have taken 4 units to get over the hill, still takes 4 units.
Date: 09/01/15 10:07 Re: DPU question Author: PHall Isn't the biggest savings the fact that you only need one crew and not two?
Date: 09/01/15 10:29 Re: DPU question Author: Pacific5th It also reduces the ammont of HPT needed for hills and such. For example conventional trains taking the ex-NP Low Line out of Spokane need 1.4 (mabey 1.6?) HPT to get up the hill to Marshall. With DP units I have done it at 1.1HPT.
Date: 09/01/15 11:46 Re: DPU question Author: cascadehogger UP did away with HP per ton because it's not as accurate as tons per equivalant powered axle. One of the few things I agree with that UP did. A train with 3 GP40-2s would have the same HP per ton as 3 SD40-2s, but less EPA.
A few of the benefits I like about DPU is the fact that I can accelerate faster from a stop, and have another automatic brake valve cutin back there for chraging the train back up. Date: 09/01/15 11:51 Re: DPU question Author: portlander PHall Wrote:
------------------------------------------------------- > Isn't the biggest savings the fact that you only > need one crew and not two? Fuel savings is also a huge factor. Posted from Android |