Once they don't need them anymore, they'll be sold or scrapped.
Agreed, there is a reason the AM1s are being replaced, they are old, and worn out. Why keep them around? Amtrak must be keeping their fabricating department busy making out of production parts for the AMI s and IIs.
And before someone mentions the VIA's Canadian train. If VIA could replace those 60 year old cars with new equipment, they would.
Want to start new corridor services? Then have the state order more brand new Siemens cars, it will for a better first impression then a refab 40 year old car.