Tunnel Rock Securement Fallen rocks inside a BorderTransportationSystem tunnel on the right-of-way can be very dangerous, especially to a railcar that is traveling at 250 MPH or more.  Fallen rocks can also be on the outside of the tunnel and block the tracks and tunnel entry / exits. There are several High-speed rail systems in the world, and there are specifications for just about every aspect of these systems, see below for detailed information. Index of ... Pressure Prevention - Click here California High-Speed Train System High Speed Rail Solutions for the US