New Jersey Transit says autumn, not winter, is the most difficult season on the rails. 

This is because in winter, trains are able to travel right through most of the snow that accumulates on train tracks.

During the autumn, falling leaves present a problem. As the leaves get ground up by numerous passing trains, they turn into grease that coats the tracks and makes it difficult for the train to get any traction.

NJ Transit has an interesting piece of machinery called AquaTrack to clear those tracks. The machine works like a power washer, and uses water to clean the tracks. The machine pumps out 20,000 pounds of pressure per square inch.

Tracks are cleaned two times a day, seven days a week. The agency has been using the AquaTrack for the last several years.