The Amfleet series of passenger cars was built for Amtrak by Budd starting in 1975. These cars use GSI General 70 trucks - a lightweight, inboard bearing truck designed for high-speed operations.
Trucks in this style can be found under Bachmann's line of Amfleet I cars -
Bachmann's original version (dating back to the 1970s) was, um, slightly more primitive in its "detailing" (with said detailing, I guess, being part of the carbody rather than the truck itself) -
Kato also makes trucks in this style (Kato catalog #800131, Inside Bearing Truck, Black w/ coupler, 2 ea). These trucks are designed for Kato's Amtrak Amfleet I and Amfleet II cars -
(New Bachmann) Wheel Diameter 0.225" (scale 36")
(New Bachmann) Wheelbase 0.626" (scale 8' 4")
(Old Bachmann) Wheel Diameter 0.218" (scale 36")
(Old Bachmann) Wheelbase 0.621" (scale 8' 4")