I've mentioned before that I think that the state of California ought to consider developing it's own reservation system for high speed rail and Amtrak California rather than pay large fees to access Amtrak's antiquated ARROW system. In addition to possessing rather more flexibility than the current "X number of seats at Y price," such a system would also allow for increased ridership and passenger revenue generation through personalized ticket prices, as Amazon has done for some time and now grocery stores are beginning to do.
Building such a new reservation system also allows a seamless integration with the panopticon that modern data collection has become. Consider, for example, a business professional who has made somewhat regular trips between two stations with Amtrak. Knowing this, the reservation can be tied into Caltrans' Quickmap and push a notification when there are traffic conditions increasing the value of taking a train relative to that of driving and offer an appropriate ticket pricing. Alternatively, a discount might be offered if a habitual, but not always taken, train is predicted to be operating with excess seats unsold. This is to the benefit of both the state and the passenger. The passenger receives a discount while the state fills another seat at a profit (assuming that the fare covers all incidental costs of course).
Such a system would also allow for a proactive response to sudden events which increase demand, such as a major traffic accident closing down lanes on the interstates or another power outage causing complete chaos for the roads, increasing ticket prices and passenger yields. It might not be terribly popular to do that, of course, which ought to be taken into consideration during system deployment, but it does present a potential means of increasing revenue.