Ask HN: Google Flights for Trains?

[qalter]

Google Flights is really good and my go to service to find the best flights for my situation.

Do you know any service that is just as good but for trains? I know Google Flights integrates trains somehow but just not to the same extent.

If there isn't any similar service, why do you think Google doesn't build the same service for trains? What could convince them to do it?