Zoomable Google Maps show the most interesting locations throughout the country where Amtrak trains switch between different lines, along with Amtrak routings serving various old Union Stations.

The downgrading of the line providing direct service, has resulted in Amtrak's Sunset Limited using a freight bypass route, stopping at a suburban location.

Martinez To Port Chicago CA
Amtrak's San Joaquin trains mostly use a former Santa Fe route, but use former Southern Pacific trackage in the Bay Area, which required a new connection between the two railroads.

Sandpoint ID
The Burlington Northern merger resulted in track consolidation for two formerly competing railroads, notably through the Spokane area.

The Union Pacific trackage in southeast Wyoming was not ideally suited for trains between Denver and points west. Amtrak service operated backwards between Denver and Cheyenne, until the downtown Cheyenne was replaced with a new outlying station at Borie.