AFAIK most electric motive locomotives use diesel engines to turn a generator to produce the electricity. Electric motors have fantastic torque, which is great for pulling heavy and slow.

At highway speed, air resistance is the main force that the engine has to overcome.

Drag is very important at high speed, as drag increases as the square of the velocity. This quickly becomes the dominant factor in terms of energy expended than getting to speed if you are traveling fast and far. This is why cars all look like lozenges these days. Maybe if there was a slow lane for EV semis? But then you have a train...

I am not an engineer, but electric motors lose torque at higher RPMs, whereas engines reach peak torque at higher RPMs. This may be another reason why ICEs are better for long haul trucks. They produce more torque at high speeds. I'd like to know if this is a important factor. I believe Tesla sedans are direct-drive, so they aren't gearing to compensate for this in the cars. Not sure about their Semi.

Finally, and perhaps most importantly, the energy density of gasoline is much higher than batteries, so even though the engine might be 1/3 as efficient, it has the luxury of a very efficient fuel.