Did you do this?

 In the 1950s, we would put pennies on the track and come back later to collect the squashed pennies. 

In 2006, when I arrived at grad school on the train, I noticed a family waiting by the tracks. The didn't get on the train. Instead they waited until the train left and then gather up the squashed coins they had placed on the track. 

What do you know? Kids are still doing this.