It is a combination of 2 or 3 Thruway buses and one or two trains...
Yeah, Amtrak is kinda train/region-specific, and many local/regional services are funded all or in part by the host state.
I understand California - by law - requires Amtrak to accommodate bikes on its state-funded Thruway - and allows state-funded Thruway to compete with for-profit intercity coach companies.
https://amtraksanjoaquins.com/bus-routes/