Siemens is offering the
American Pioneer 220 and is building a new factory in NC that should allow them build the train in CA. Siemens seems to be thinking that they can modify the existing Velaro Novo design.
I can't tell what in Alstom's portfolio is their proposal, but I'd be surprised if it wasn't based on their Avelia platform.
The Velaro Novo designs for Europe have a in service design speed of 360 kph ( 223.69 mph) and the Alstom Avelia has a design speed of 350 kph (217.48 mph), which makes me think that CAHSR's 220 mph for regular operations requirement is achievable with existing designs.