I wonder whether we will first see a route *abandon its Heritage*, or whether we will see a *Restoration*. (Hoping for the latter.)
Sorry, I know the Lake Shore Ltd is your train, but I'm hoping it gets new diners last. Among the many advantages of the new cars should be improved reliability in every way. One way that matters a lot to Amtrak, is cars that fail on the NEC, and cars that go slow on the NEC.
When ALL the slow and failure-prone Heritage cars are gone from the NEC, the On Time Performance should improve for ALL other trains. You can't get the full effect you need with many new cars replacing many Heritage cars, or replacing most of them. It's ALL or nothing. And it's worth it.
So the one and only LD train that never operates on the NEC should be the last to benefit from new diners. Such is life.