I made this train cake for my son's (who is a train FANATIC) 3rd birthday. The base is two 13x9 cakes laid side by side, the cars are each 1 mini loaf cake and the engine is a mini loaf on its end (held in place with toothpicks) with a cake I baked in a mug in front (I got the recipe off the internet for the mug cake).
I used 3 boxes of cake mix- one for each of the 13x9 cakes and one for all of the loaf cakes. For decoration, I tinted white frosting green for the "grass" and spread it across the two base cakes to join them and then stuck my knife to the icing and pulled directly up to create a "grassy" effect. Then I added flowers made of Mike n Ike candies. The track bed "gravel" was grape nuts, I used mini kit cats for the ties.
I cut the Kit Kats in half and stuck them on either side of the cars rather than putting them under the cars. My plan was to use pull and peel black licorice for the tracks, but I could only find red. As it turned out, you really couldn't see where the rails would have been anyway so I just went without.
For the cars, I tinted white icing different colors and iced each cake after leveling off the top. I had a zoo car with animal crackers, a lumber car with pretzel rods and a coal car with chocolate covered peanuts. For the engine, I used chocolate icing to cover and join the two pieces, a yellow M&M headlight, an ice cream cone smokestack (just the bottom) with marshmallow smoke, (I used a toothpick to hold them together) a Reese's peanut butter bell (from Christmas time), and I took pictures of my son in his engineer costume from Halloween from the front and back (one angle for each side of the train), resized them and printed them out on regular paper before gluing them to a cereal box and sticking them to either side of the engine so it looked like he was driving.
The wheels were mini and full sized Oreos. I assembled everything on a tote lid that I covered in foil. It was perfect- it was the right size, was sturdy and had handles!