Since David wanted to be the conductor and conductors don't drive the train but ride with the passengers, we decided to make David a car, much to his initial distress. I figured if worst came to worst, Engineer Peter would ride with the passengers and the conductor would take over the engine as Peter wouldn't care. Fortunately, we were able to talk David into the car with a clever paint job. It is "trolley inspired"; we looked both at the trolley from Mister Rogers' Neighborhood and the Duquesne Incline, which we rode once several months ago, and David still likes to talk about. Evidently we did a pretty good job because David took one look at the car after we painted it and declared it a trolley.
In order to make car we first took a diaper box and cut out most of the bottom, leaving about an inch around each side for stability. Then we cut the short top flaps off to shallow curves and used a high temperature glue gun to glue the long flaps over them to make the roof line. We cut a hole out of the center big enough for David to fit inside.
For the roof we used another box to put together
a piece that fit around the hole and hung off the first box on all sides. We built miniature versions of the car to place in the center of the roof each with their own roof.
We painted the body and the roof separately. I used repositionable spray adhesive to make stencils out of paper for all the stripes and windows. the painting process was a bit tedious but it was certainly the most important part for David.
After all the painting was done we added the centers from small paper plates as wheels and glued on the roof. We added a bike light to the back of the car and straps to hold it on. David ended up having no more concerns about not having the engine.