I can't see this working at all I'm afraid - mainly for the inconvenience factor. Having to order food online three days in advance, for a specific train at a specific time, just isn't going to appeal to most people. If you could order from that menu onboard, from staff or via the trains WiFi, then I could see it working. Can't they fit a freezer in the galley?
Then there's the questions over what happens if your train is cancelled / delayed / has no catering staff / missed due to connections / wedged.
It's a valiant effort, but I suspect that passengers will want to see it working - ditto for their irritating adverts saying "I hope know there will be food on the train ..." with the disclaimer that it's only available on selected routes and may not be available then anyway.
Here's an idea: since the Voyagers used to have at-seat "radio", I wonder if the disused conduits could be reconfigured to deliver piping hot casserole directly to passengers laps?