Note: There was one train in service on Mars at this time. It was a slow, solar powered monster which ran directly from Mars City to Mars University with only one stop in between at a small arcology. The safety system mentioned would have been an instant-foam solution, which would have filled each cabin with a light, flexible, air-permeable, fire-proof foam to cushion impact. Not comfortable, and takes a few minutes to dig out of after the crash, but keeps everyone safe, when it works.