DJ of DJsTrains
Sep 8, 2019
Great short but concise video with modeling with in mind! THX!
Hey DJ, I didn't know that DJs Trains also owned a fleet of railcars. Captured today in Columbia, SC.
Old coal gons never die, they just get pressed into scrap hauling service.
I have heard other engineers on other properties mention a 'fence' that can be established between the head end power and the DPU - is CSX operating procedures authorizing the use of the 'fence'. I doubt that once the head end has crested Sand Patch you would want the DPU to be mirroring the head end power until most of the train has reached the critical point in the transition from pulling to braking.
Yes, we can use the fence. I run on flat territory where we really don't even need DP, but since the company paid for it, they insist it be used. I actually have one spot where I put up the fence for about 3 miles on my normal run. More of a personal preference thing for slack control.
Also, only AC traction locos can be DPUs.
When you put up the "fence" what does the DPU unit then do?
With the 'fence' up - each locomotive consist can be operated independently of each other.
In the situation I presented in my original post in this thread. At some point after the head end locomotives have crested Sand Patch grade, the engineer will be wanting to apply Dynamic Brakes to the head end consist to keep the train under control as it is now on a descending grade, meanwhile the DPU, either mid-train or on the rear end is still in power getting the rest of the train upto and over the crest. Once all sets of power are operating under nominally the same conditions, the fence can be removed, and the power can operate in unison.
There is a combination of power/dynamic that cannot be applied even with the fence up. I don't have enough experience using/needing that combination to know for sure which is which.
Trip Optimizer manages power and dynamic use during such cases, and my particular run doesn't use TO (thank goodness...).
DPU units can be AC or DC - any locomotive that has had the DPU control electronics put on its control stand is able to be a DPU unit - either leading or in train. In train units either AC or DC that are MU'd to a DPU unit can be controlled by that DPU equipped unit.