Here's a little train that I made for Ronda's Creative Convention in Sept. My theme was Christmas Gifts and while the train isn't sturdy enough to play with it did have a lot of candy in it for the dispaly. I don't have any dimensions for it. I just kept playing with it and when something looked right I moved on to the next piece but maybe you can get some ideas from the pictures and the few hints that I have.
This engine is made with a flat box for the base, toilet paper tube for the boiler, a box for the cab, peppermint sticks for the roof supports and some of the wood grain DSP for the roof. The wheels are from the Jolly Bingo Bits. I did make them several layers thick so that they're studier. I also cut cardboard and filled the flat box that is the base. I always save all my cardboard and this worked great to make the base study. It really should have had a cow catcher and a bell but I ran out of time.
Here's a close up of the wheels. I got the idea for the snowflakes and the peppermint candy from a train that I saw at Bronners.
Here's the coal car. Just an open box for the car and I filled it with black jelly beans.
An open box car that I filled with Hershey Nuggets. This car is a little taller than the coal car.
And a gondola car that I filled with the long Tootise Rolls it looked like a log car. The tress are also several layers thick. So while it really can't be played with much it would make a cute gift for a little boy. Or even a big boy.