I mean, you could build an active cooling system for the tube, and start it up whenever you have a broken-down pod radiating heat into the tube, though that see

I mean, you could build an active cooling system for the tube, and start it up whenever you have a broken-down pod radiating heat into the tube, though that seems like a lot of effort / complexity. Maybe the focus should be on how to get people out of a broken-down pod within a reasonable period of time rather than cooling said broken-down pod. Unfortunately I don't have any ideas on this front.