Higher HPT as a way of increasing speed and thus fluidity, is not a new idea. But, it is only one of the factors in overall fluidity.

Lack of terminal capacity is one problem that it doesn't solve, and, at least at the POLA/POLB, where the terminals capacity to receive trains and assemble departures is what is being overwhelmed. It only get the train to the yard limits faster, where it sits and waits for capacity to open up, backing up the line.

I can say that I have hauled 7-10 thousand foot, 7-10 thousand ton trains, with the minimum HPT 2.0 HPT with helpers for Beaumont) 2.5 HPT...., you go so slow, you could drop off and catch to the passing rear unit to reset a low oil button.... That kind of stress on the engines also seems, in my experience, to cause more of that kind of problem with the consist you are operating. It an engine fails, it leaves you with no "reserve" of power to call on and compounds your low HPT related problems.

And, I've run the same trains with plenty of HPT (3.5 HPT+). And with more HPT, you get the damn things started and moving a lost faster and a lot higher speed, it is as simple as that.

It was also my experience that you had less knuckles and drawbars, since, if you knew what you were doing, as you had less potential for slippage and jerking, because you had more steady and solid power to use. If you have a higher HPT, you will also most likely have more dynamic braking, requiring less air to control the train, and never having to do things like stopping to set retainers.

So, if you look at avoidable delays from events, as one cause of fluidity loss, and more usable mainline track space, as fluidity parameters, then yes, more HPT can potentially improve fluidity.

I fear, however, that the biggest problems right now are a lack of sidings, a lack of terminal capacity, a lack of crews, and poor crew utilization. The first two are much harder to fix.

Better advanced blocking to make better use of terminal capacity at the POLA/POLB is one way BNSF is trying to deal with that terminal "gridlock" problem.

But, if you can't yard the train, load it, unload it, or switch it out, when you get to the terminal, it doesn't really matter how fast you got there.

But, as we use to say on the old SP: Up the hill slow, down the hill fast, it's tonnage first and safety last.....