what are the implications of serious damage to the pipe/waveguide? Either explosives from the inside or outside, or just damaging the support struts. If it's u

what are the implications of serious damage to the pipe/waveguide? Either explosives from the inside or outside, or just damaging the support struts. If it's using the air-hockey principle, I'd expect reduced forward pressure to below the limit on which the vehicle can float, so it starts to skid along the ground, hopefully with enough inter-car spacing that you don't get a pileup. A less catastrophic situation might be, what happens if the pipe has a relatively minor leak due to subsidence or whatever? Just a loss of efficiency, or loss of function?