When money was flowing for passenger rail around 2009 or so, Amtrak (and the FRA?) set up committees that worked out the specifications for any new bi-level and single-level cars to get any federal funding in the future. Height, length, weight, crash-worthiness of course, door and window placement and operations, number of electric outlets, and many other details are covered by the specs. New specs were agreed before the order was made for the Nippon Sharyo bi-levels. Later the specs for the single-level cars were agreed to.
The new single-level cars that Brightline/All Aboard Florida is buying from Siemens will meet these new Amtrak/FRA specs. (AAF and Siemens said so with the purchase announcement.) Nicely for Siemens, the American design specs almost match an off-the-shelf model that Siemens sells in Europe.
Now Siemens will have an open assembly line in Sacramento making a compliant American version. So the AAF order covers some of Siemens set-up costs, giving them a real advantage over other bidders in any near-future round. The Siemens order from AAF could turn out to be the launch order for 700 Amtrak single-level coaches and cafe cars.
I've read that Amtrak played around with a mock-up coach version of the Viewliner shell. Maybe CAF can make that work with their open assembly line. But they'd have to meet the Amtrak/FRA specs.
Of course, any car maker can bid, and build a new plant or at least a new assembly line and train the employees. But those other bidders will be 6 months to a year behind the delivery date that Siemens and CAF could offer thanks to their open production lines.
Siemens in particular would seem able to spread its start-up costs over both whatever batch of coaches Amtrak might order and the few dozen cars it will build for AAF, allowing Siemens to make a lower bid. So while it could be anybody, bet on Siemens if any batch of 50 or even 700 replacements for Amfleets gets ordered in the next few years.
