I need instructions on assembling a 3-D thomas the train cake.

are u making it with fondant or buttercream here r a couple of videos

If Mommynana's suggestion doesnt help i could give you a copy of the step by step instructions i have x

I made a Thomas cake recently - I bought the Wilton Choo Choo train pan and it worked perfect!
I decorated it as Thomas looked. For Thomas's face I made it out of fondant using the same link as above

http://thomasthetankenginecake.blogspot.com/