Investigators say Strantz' car was heading south on a city street when it took out a fence on the top of the bridge and then fell onto the tracks below.
A train was coming at the time, but the conductor was able to stop in time and call for help.
Police don't yet know what caused the car to leave the road. Investigators are looking for witnesses who may have seen the car go off the road.
South Bend Sgt. Bill Kraus tells WSBT-TV that the deadly incident is "an unusual one."