For what it’s worth, this is a video on the old Metroliner’s in action blowing their K5LA’s horns. Now that I’m farther than ever away from the northeast where they can be found on the Keystone Corridor and Hartford Line.
The original Metroliners pretty much existed as a flop thanks to poor design choices and trackage that left something to be desired. Luckily, Amtrak didn’t give them the scrappers torch when Penn Central’s trains were handed over to them. With the introduction of the new AEM-7’s to help in tandem with the new Amfleet coaches, Amtrak was able to cement the standard Keystone set which arrangement of one engine, usually four Amfleet cars, and an engine.
Nowadays you can find these cab cars today albeit with introduction of Siemens’ new lines of ACS-64’s as well as testing made with new coaches made by them as well.