I don't see Amtrak doing it, but NY MTA has done it with buses where the proposals were close, and in order to shorten the time line orders were split between NOVABUS and New Flyer, but those are individual units not sets where so much more interoperability stuff applies. There have been some subway car orders where different mfrs built follow on/options instead of the original prime, but again, that is not likely the way this acquisition is laid out.