And maybe this newfound profitability of passenger rail will increase the pressure to change the regulatory enviornment and make such a thing feasible. There are, right now, many many obstacles to running passenger trains, and even more to running them quickly and efficiently. Start with the fact that most tracks are owned by freight railroads, who are not at all interested in running passenger trains, even if they get all sorts of incentives for it. And they're even less happy about anyone other than Amtrak running passenger trains. You're not allowed to operate on their tracks without getting $800 million of insurance. I suppose that's in case your train crashes into a train full of dynamite, which is standing next to a train full of chlorine. In the middle of a city.
And assuming you manage to overcome that hurdle and actually get a train going, you still have the issue of trains here being very heavy and inefficient, due to outdated and frankly arbitrary regulations about collision strength and so on. Remember all the problems with Acela? Parts started failing because they were designed for a much lighter train, and Acela is about twice as heavy as the TGV on which it is based. There's a nice explanation of these things at http://zierke.com/shasta_route/ in the context of an analysis of a specific route for feasibility of better passenger service.
In England several years ago, a Land Rover towing a trailer, drifted off the motorway, down an embankment and lodged across the railway line. The land rover driver went for help. An express train travelling southbound at 125 mph hit the SUV, derailed but continued for another 400 metres before crashing into a freight train, carrying 1,600 tons of coal, travelling northbound at 60 mph. Ten people died and the land rover driver was jailed for 5 years. Freak circumstances can happen.
Yes, freak circumstances can happen. But planes aren't required to survive a collision with the ground: if they were, there would be no planes. Cars aren't required to survive, without deforming, collisions with a brick wall at 60 mph. Trains are already safer than airplanes, and much much safer than cars. If, as a result of these regulations, there is no train service, and people are forced to drive instead, are we really  improving safety? Unless you were talking about the insurance issue, in which case that's still not nearly $700 million dollars worth of damage. Probably less than $70 million, in fact.
I seem to remember a quote of £2 billion for the accident from the insurance companies being bandied about. I was surprised by how high this number was, but have no idea how accurate it was, as the quote was from the first day of the accident, not a considered quote after all the details had been found out. I suspect £2 billion would be the figure needed to correct the problem of upgrading all crash barriers by railway lines.
Basically, what it comes down to is this: the insurance requirements of the railroads are the equivalent of requiring all planes to be insured against crashing into a World Trade Center.