For many children, nothing is as much fun as playing with toy trains. Small children are not sophisticated enough to handle electric trains, so other, simpler toys must be used instead. Making your own trackless train that can be run on the carpet or floor can give a child hours of railroading fun.
Cut the blocks to traincar size one at a time. Use sandpaper to round off the corners and sand down the front of the locomotive to a round boiler. This may require the use of a hand moto-tool. Make some diagonal relief cuts in the loco piece and cut off as much as possible before starting to sand.
Paint the cars if you are going to and coat them with sealant. Wait for the paint to dry and then either paint, draw or apply stickers to make doors and windows in the cars. The larger the blocks you use and the more detail you add, the more realistic it will look and the more fun it will be for your child to play with.
Drill small holes in the bottom of each car horizontally for the axles for the wheels. Insert the axles through the holes and insert pins through the axles to keep them in place. Attach the wheels, using glue if necessary.
Attach magnetic couplers to the cars. These can be purchased from a hobby store. Also, you can just glue one continuous string under the cars to make the train whole.
Glue a string or strap to the front of the locomotive so that a child can pull it around by that. Make a loop that the child can put his hand through. Paint a face on your locomotive if you want to.