The streamlined Obs (to use a USA short form for these) in the third attachment was from the 1937 LNER Coronation London to Edinburgh trainset. Stored in WW2, it later got used on odd excursions (Ian Allan knew of it and used to hire it for his early enthusiast excursions, when he and his invited authors etc used to use it for a private party at the rear). It came to the Scottish trains in the 1950s. View out was actually poor and seating was limited, the inner half of it was a buffet-bar, so it was later rebuilt at St Rollox works more squared off, with larger back windows, as seen in the fifth attachment.
We had a discussion here a while ago about, when it arrived steam-hauled at Mallaig, how many shunts were required to get both it and the locomotive separately turned on the turntable and then get both onto their respective ends for the return journey, as there was no shunting locomotive there and given where the turntable was located - it was about 20! Must have taken the best part of an hour.
The separate car in the fourth attachment was an ex-Pullman, rebuilt as such in their own works for the early 1950s Devon Belle from Waterloo to Ilfracombe, which train had been a conspicuous commercial failure and so had not lasted long.
The slightly later "inspection saloon" is I believe a 1930s Gresley coach, built as such. These saloons were used as much by the commercial department to take key customers (principally freight) around the system, rather than for engineering inspections.
