Acceleration
Getting to 2500 mph in 2 minutes, cruise at 2500 mph for about 56 minutes and then slowing down for another 2 minutes is reasonable. Electrically driven linear motors could do it. The vacuum can be created and maintained without too much trouble, just have a large turbine engine suck the air out. The tube would have to be pretty straight and very gently curved. My guess is that like the English tunnel it is 3 side-by-side two larger ones and one smaller service tunnel. Not sure what that buys you with the vacuum though.
the real question is what are the economics of building it and operating it compared to the next best thing, like airplances. Jets require no tube, rails and vacuum, only endpoint services like an airport. I am thinking an advanced semi-ballistic rocket flight up 20 miles or more and then gliding to a landing might be cheaper.
