The fireman casts me a glance as the National Limited heads west to Harrisburg after a station stop in Lancaster. The train is about 3 miles out of Lancaster and is already running near track speed, which was 75 mph. Today, there are no active grade crossings on this line, known as Amtrak's "Keystone Corridor." No. 922 was built by Altoona/Westinghouse as the PRR 4928, in October, 1942.