Why, why, why would you design Toby so that the slightest little jiggle will cause the batter to fall out of place? Even when replacing the battery, you have to put it in just right (partially suspended between the battery terminals) so that he will go. That means there is air above, below and on either side of the battery. I have tried taping cardboard together in there or rigging something so it won't fall out, and it just doesn't work. I get sooooo sick of "fixing" Toby 10 times a day, and it seems now even my son has given up trying to make him go. Toby often just sits there off the track as my son plays with his other engines. :((
UPDATE:
See comments, thank you to the lovely person who told me Toby needed a C battery. Slap me and call me stupid!