My son just turned 3 and he told me he wanted a choo-choo train cake but he did not want Thomas. Which was really odd cause he loves Thomas, but that was his stipulations. So this is what turned out.
I made one-13×9, one 8×8, and one empty soup can of cake made from one recipe chocolate pound cake (much sturdier and easier to handle then regular cake mix). I cut the 13×9 cake into 8 pieces which made two pieces stacked on top of each other for each boxcar. The 8×8 cake I used 1/2 for the bottom of the engine, and two squares stacked on top of the bottom layer for the back of the engine(making it 3 layers stacked).
Then I used the soup can cake for the round part of the engine. I used a plain shortening/vanilla frosting tinted with Wilton gel colors to hold everything together. I used a medium size star tip to cover all the cars, and did the two-toned color on the engine simply by putting two colors frosting in the bag and piping.
The tracks are chocolate wafer cookies, the dirt is cocoa powder, and the grass is tinted coconut held on with green frosting. I cut out holes in the cars holding the malt balls and jelly beans, or else they have a tendency to fall off. The other two cars are holding kit kats(timber) and mini candy bars(logs).
The wheels are peppermint patties, and I used ribbon to link the cars together. The smoke stack is just a candle with the birthday age on it, and I used a regular photo to put my son in the drivers seat which he thought was awesome!(held on with a dab of frosting).
It took about 5-6 hours to decorate, but was well worth the time! It was a big hit!