Well in case you didn’t know if you get into the lead engine,as you back into and attach each rail car you unlock them one at a time
Viewing post in FS25 Placeable Railroad Track comments
hey sorry for the delay! But yeah as my friend Nsideous said, when you connect the locomotive to the railcars on the straight piece, you can unlock the trucks from the locomotive as you connect them! Once you have them on the tracks and unlocked, you shouldn’t really ever have to mess with them again.