make locomotive less wide to make it have a correct size because it is very wide not like in old factorio

Not sure I understand

It looks too long when on a straight track

Sadly that's how the old train is, I would need the original 3d model to fix that. I can change the internal size of the train but that messes up the train stops so this will have to do for now. I am planning on remaking this mod however and I'll see if that is possible.

You can use the same as in Armored Train (turret wagons) mod