The ghosts of all those kids down at the railroad tracks are there because once 100 kids put 100 pennies on the railroad track and it made the train derail and it ran off the tracks and plowed into them and they all died.

Or maybe there were 100 kids on the train and it derailed when it hit the pennies. Which means they had to put the pennies on the track and then go get in the train to drive them over.

It's like the story of the counterfeiter who could make perfect counterfeit, but realized he'd attract attention if he had money but no job, so had to get a job and work all the time to cover for it.