With this mod trains can spend the majority of their trip coasting off of their initial burst of acceleration. I currently have a train whose journey is so long that it always runs out of fuel a third of the way into the return trip yet still makes it back every time. However, if this train does have fuel it is consumed at the maximum rate for the entire journey, even after the train has stopped accelerating.

Is this intended behavior? I love this mod but it is bothering me that my trains are consuming fuel that demonstrably does nothing.

This is a fair point, I'll look into it. I didn't take the case of a train of out fuel into account in my development/testing.

I created a new mod (in beta!), which hopefully side-steps a lot of the issues of this one (that has to adjust the train-speed every game-tick).

This mod changes the weight of the train-carriages and let the game-engine just do its thing:
- https://mods.factorio.com/mod/TrainMass

You'd have to deactivate the current TrainSpeeds mod, because they obviously will interfere :)