> one doesn't get a sense the train would roll very far unpowered Even a model/toy train wagon can easily coast the length of a large room when given a push.

> one doesn't get a sense the train would roll very far unpowered Even a model/toy train wagon can easily coast the length of a large room when given a push. See how little metal is in contact, about 1cm²: https://www.reddit.com/r/Damnthatsinteresting/comments/17ysdb8/this_is_the_size_of_the_contact_patch_between/ https://www.reddit.com/r/Damnthatsinteresting/comments/17ysd... There's very little friction.