You technically could do that… at least on a relatively short, flat, straight track… but it doesnt make any practical sense.
First, its a ram jet so something has to get it up to speed before the ram jet starts working. Though if we just make it a scramjet, there we go.
Next problem is … it might actually need downforce winglets on it the way drag cars do. On every car. Hope there is no sudden cross wind on your nearly perfectly straight track in a large flat area. Now you need a computer system to automatically move the winglets to counter cross winds… or you need some kind of… train… pilot…???
Biggest problem is: The speeds capable by a theoretically working scramjet train would mean it could not turn on anything other than VERY wide arcs, and it wouldnt be able to get to the speeds capable of a scramjet… ostensibly the whole point… without skipping tons of stops a slower train could make…
…unless you are going to slow the thing down at each stop with a series of parachutes coming out the back, or some how be able to reverse thrust the scramjet?
As far as I know there are no reverse thrust scramjets, fairly sure thats impossible due to the nature of scramjets.
???
