Factorio Forums

If you mix railway carriages with different connection distances the separation distance is based on their facing to each other.
If they are both facing the same direction then the leading carriage applies its connection distance and the trailing carriage value is ignored. If the direction of the carriages is different then the placed carriage seems to apply its connection distance.

In the screenshot the locomotives have very short collision box, joint and connection distances. With the cargo wagons being vanilla. The carriages are all facing the same direction in each line.
I would expect the spacing between the locos and wagons to be equal on both sides, rather than varied. Ideally I believe the distance between the 2 carriages should be half of each carriages connection_distance added together. I don't believe this would have any impact on vanilla or trains made of only 1 carriage connection_distance, but would fix this mixing of connection_distances.

I was experimenting with a mod to add longer locomotives to use with vanilla rolling stock and came across this issue as well. It appears that whatever direction the train is going, the connection_distance value used is that of the wagon to the rear of the connection. For example, consider when the locomotive has connection_distance=5 and it is pulling a wagon with connection_distance=3. When driving forwards, the wagon is 3 spaces away. When you switch to driving backwards, the distance stretches to 5 spaces (wagon is pulling locomotive now). When you switch back to forwards again, the wagon jumps instantly back to 3 spaces away from the locomotive.

It would be great to have this bug fixed so that longer locomotives can have longer wheel (truck) sprites and still connect to other wagons normally.

This was fixed as part of trains movement fix for 81102

Yup finally got back to my crazy train length mod and I can now mix and match connection lengths, cheers