I am wondering, just maybe, you might be thinking that the term "silver service" refers to a certain category or class of service. Such designations are not uncommon in the travel industry. I believe the VIA(Canadian Rail) uses some such terminology these days, maybe "silver and blue service".
Actually, the term came from such trains being built of unpainted stainless steel back in a day when that was a genuine novelty. The Silver Meteor began operation in 1939 and the Silver Star(and a now-defunct Silver Comet, pre-amtrak) in 1947. Stainless steel or other light weight construction was a prized advancement then,not the norm it is today.
I have learned from Alan, a moderator on this forum, that some even think silver service refers to the silver-haired elderly folk frequenting such trains, including the Auto-Train, for the winter in Florida.
Now, if your question had nothing to do with any the above, then I would defer to those on this forum who have much more experience with them than have I.