The Chicago Transit Authority has a message for riders: stay off the tracks.
The rail and bus service is rolling out a series of new public safety ads Monday.
The Chicago Sun-Times says the number of people making their way to the tracks is up about 4 percent. In 2012, there were 349 reports of people leaving train platforms to climb onto the rails. Last year, 11 people died on the tracks, up from 9 in 2011.
Officials say many of the people on the tracks are trying to retrieve fallen items.
The messages warn people about how quickly trains can approach. One says: "You can live for a few minutes without it. If you drop your phone on the tracks, don't jump down to get it."