I know the observation car normally comes last if that helps.
Except on Reading's Crusader, as I understand that train's consist. It was right behind the tender....in both directions.........because it had an observation car at both ends to avoid turning the entire train. And the tender had an 'alcove', I believe, on it's rear into which the 'front' observation car would nestle, belying its round-end presence. Very clever.
Those fortunate enough to have one of Weaver's rendition of this classic passenger set.....chime in. Two observation cars in the set? Right?
About 60+ years ago I also learned you can be the engineer while sitting in the rear seat of a boat-tail observation car. Yepper. When the family would ride B&O's Columbian home from vacation in the midwest (Mom's family visit), the train would take the wye in order to back into Union Station, Washington, D.C.. That's because it subsequently traveled further 'east' (more like north!) to Baltimore, etc.. later on. Mom would let me go by myself to the observation car after our last stop eastward at Silver Spring, MD, to watch the conductor back the train into the station.
Well, truth be told, what he was doing was communicating with the engine's cab via an air signal line located behind a door just beneath a rear window, left side. Stop, start, horn, speed....he had a set of signals that told the engineer exactly what to do. And the fact that the tail car stopped perfectly within a few feet of the station bumper, amazed this oogly-eyed kid beyond words.
And, since Dad usually didn't make the month-long trip with Mom and my two sisters (he was the breadwinner, of course.) he would be waiting for us at Union Station....at the bumper, knowing I'd be there in the observation car to wave to him!! The perfect ending to a perfect vacation.
And people wonder where I got my love of trains?.....
KD