[pschlik]

Evening gents, today I decided to have a try at implementing the ETS features on the Streamlines Empire Builder trainset. In the case of a train like the Empire Builder, multiple locomotives are attached to the front of the train but only the rearmost locomotive in the multiple unit will actually supply electric power to the train.

To simulate this, I have two configurations of the P42DC-one developing the full 4250 horsepower with HEP turned off {in the engine file, ORTSElectricTrainSupply ( Mode ( Unfitted ) ) is used}, and a second maxing out at only 3540 horsepower (with rail horsepower in the tractive force curves set even lower to simulate HEP draw) with HEP turned on {in the engine file, ORTSElectricTrainSupply ( Mode ( Automatic) ) is used}. I then modified the passenger stock to draw a constant 85kW to make sure everything is working (85kW would normally be the absolute max power draw Amtrak would allow per coach). Note that I am not using MSTS physics, I am using ORTSDieselEngines and ORTSMaxTractiveForceCurves.

What I expected to happen was that the lead locomotive, where ETS is set to unfitted, to be completely unaffected and the rear locomotive, where ETS is set to automatic, to take the entire 765kW load of the 9 superliner coaches (800kW is the max a P42 should be allowed to handle, but I saw no parameter to set the max a locomotive could supply). Instead, I'm finding the load to be evenly split between the two locomotives even though the lead one is unfitted!

In the power supply information HUD, it can be seen that the 9 coaches are correctly drawing 85kW each (the 0kW thing is a baggage car), and the trailing locomotive is reported as having a 383kW load. Of course, 383kW is only half the load...the HUD fails to show that the other half of the load is going to the first locomotive.
https://i.imgur.com/KSjL9me.png

This has interesting results on the engine load readouts in the locomotive information. Because the lead loco is getting a full load from running at max throttle, then is having a few hundred kW added on top of that, the load reported goes over 100%! Oops.

https://i.imgur.com/ajU6usW.png

Something interesting I found is that if I toggle the electric train supply connection on the second locomotive, the entire load finally goes to that locomotive only, but this still has some issues. I set up the HEP locomotive with 3640 gross horsepower and 2525 traction horsepower, leaving 1115hp or 830kW available. Yet, with the full 765kW load, the load percent reported goes over 100% anyway. For some reason, the ETS load seems to reduce the engine's gross horsepower (you can see the engine is only at 2614 hp, not 3640).

https://i.imgur.com/dxoN0gm.png

https://i.imgur.com/2KMzjRm.png



Have I managed to create an edge case that the ETS setup is awful at handling (is it not meant for multiple locomotives? is it not compatible with custom diesel engines or tractive force curves?), or is this actually an issue? For the moment, it seems this will be something I have to ignore implementing.