1. "...How soon after Amtrak appeared did the E-60's show up. Were these originally a PC order?..".
The E-60 was an Amtrak purchase that showed up on the property some time about 1974, but didn't enter service until 1976, due to reliability problems . (Similar to the current HHP-8 development).
"....I know the Metroliners were originally delivered with worms..."
Actually the Metroliners were delivered with "Keystones", but didn't enter service until the PC era. (Although the first revenue run may have occurred in Pre-merger Jan 1968).
Metroliner development again was similar to the current slow development of the Acela.