The Utah Transit Authority says a man in his 20s was injured when the music on his iPod drowned out the sudden alarm of an oncoming train.
"They found an iPod and possibly some headphones near the scene," Remi Barron, a UTA spokesperson said.
A witness told ABC4 the man was waiting to cross the tracks at about 1700 South and 700 West when he lost his patience.
"He didn't want to wait I guess."
He said the man stepped onto the tracks, then came tragedy.
"He crawled underneath the freight train and started running across the tracks," a witness said. Then, "The FrontRunner came by flying at a high speed and just smacked right into the side of him."
That prompted the witness to take action.
"I got out of the truck and ran over to see what he was doing, how he was doing," he said. "He was in bad shape. He had head wounds, his leg bone was sticking out, and his arm was missing."
For that reason the witness took off his belt and used it to tie a tourniquet around the man's shoulder, which may have saved his life.
The victim is now at a Salt Lake City hospital in serious condition.
However, the accident has prompted the UTA to issue a stern warning.
"Anytime lights are flashing, anytime arms are down, anytime a train is on the tracks, do not try to cross," Barron said.
The accident caused temporary back-up in the area, but 1700 South is now open to traffic. An investigation into the accident is underway.