One thing I feel that SPG lacks is DPU action. Especially in mountain passes, they are invaluable to heavy trains like autoracks, intermodals, and coal trains. On heavy trains, with only an SD40-2 and an AC4400CW, my speed always drops to about 18 MPH on anything above a 1% grade or so. Grabbing a helper locomotive or two from the yard to attach either on the end or behind the leading locomotives would be really cool to see as it does happen quite a bit in real life. Either that or just having DPUs already on the trains would be fine as well.
Then I suggest you check out the timetable again. As I said, most manifest and autorack trains leaving Cumberland have rear DPUs.
late 1990s all the way to mid 2010s some of these heavy trains would have used AC6000CW with AC4400CW therefore you have 10,400 horsePower sufficient to make those climb. Therefore the DPU is activated on AC6000CW and AC4400CW possibly the attached SD70s if a quad locomotive formation is used with AC6000CW on SPG.
Using DP isn't just a matter of horsepower, but also a matter of coupler strain, and time for brake pipe pressure changes to propagate. Having locos at both ends, and often in the middle as well, ameliorates those long-consist problems.
