Issue with the Spawn Room that sticks out the side of the train:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607585974
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607585992

This issue also exists on Red's side:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586018
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586044

Less important, but the window facing the smoke in the Top Spawn Rooms on both sides can be accessed in multiple ways, resulting in you being able to see the smoke coming out of nothing:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586118

Final Big Problem: The front of the trains. They need to be either blocked off or at the very least, make it so Engi's can't built there.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586070
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586106

Also, you can get stuck in Blu's Bumpers:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586092
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2607586080

(This is my first time doing one of these, so sorry if it's messy)