It would be amazing if there could be buddhas on the top of the small toy train, like Tara statues or tsa-tsas.
Also, you could put Dharma messages on the side of the train, similar to the stickers on my car, so that anyone who comes into the restaurant sees the messages. If people are depressed and their life is full of problems, and they see the messages, maybe it will help them. That is the best meditation and best philosophy. If people think this way, then it stops problems and their life is saved. They are saved from killing themselves if they are suicidal, or saved from problems in their life, relationship problems. They will have more happiness in their life—at work, with others and with their family.
It is such a great opportunity and so easy to do. You could also put Universal Education messages on the train.