@straphanger those cars were first purchase of new rolling stock by AMT. bombardier had just purchased the IP from Budd and Pullman who pulled out of train manufacturing. Those AMT cars are of the Comet family, inherited from Budd with huge commonality to the SEPTA ones so easily integrated. Bombardier produced Comet cars for SEPTA and NJ Transit as well as using existing content production facility to make Horizon cars for Amtrak. Comet is US designed.