This is my own design for a pushback tug. If you would like it to be 1:400 scale I recommend scaling it down to 80% or less I say that because if you start scaling it down too much you will lose a lot of detail. I found the best balance of detail and size was 80%. For best results, I recommend you to print it where the back of the tug is on the plate. I tested all orientations and that is what gave me the highest quality print. Other than that happy printing:).

This isn't a real tug but it would probably pushback 757s and up.