the rail car is shorter vertically than horizontally. link to photo proof: https://photos.app.goo.gl/muCPikag66QtzL4j9

This is a fact of life for all Factorio trains. Watch vanilla trains as they go around corners: the gaps between them appear to get larger. It looks weird for the flat car because the wagon has no height to hide the bigger gap.

https://photos.app.goo.gl/4s8FBpf1sTbh4ZSr6

okay, i just looked at this side by side image set and it shows via the belts were the hitbox ends. the sprite for the wagon is supposed to be 7 tall and have a hitbox 6 tall but only has a sprite 6 tall. must have been a change to the wagons. I'm going to look at the patch notes. okay, so it turns out they had to hardcode the height of the wagon and width meaning that at one point wagons were 5 tiles when vertical and 6 when horizontal this was changed to 6 tall and 6 wide with a gap of 1 as default. Was this mod made before then? it may still be using the sprite that is 6 tall. (the sprite extends 0.5 tiles each side beyond the wagons to create the coupling between the cars)

https://factorio.com/blog/post/fff-133 explains what is going and why the existing graphics confirm to the official convention.

I've talked to Yuokitani and others about it. We tried different ways of lengthening the sprites when they go vertical but they all look really weird.

In a normal perspective world, you would not be able to see the vestibule door on the end of the car if there was another car coupled to it. You'll notice the "extension" on the normal wagon sprite is just the fact that the roof covers the now-larger gap behind it. A flatcar has no roof so the gap is uncovered.

I.e. the wheels under the wagon are still in the same place as they are in a vanilla wagon. If there was a better way I would use it.

oh okay

thanks

the other thing is that the bottom of the cargo wagon is the start of the hitbox but just shifting the sprite down to match that would look weird because the hitbox would still be in the center.