If my memory serves me correctly these once fine buildings were used by the Yard Chargeman,Shunters, carriage cleaners and possible by the C&W examiners.
I once visited Ponsandane Yard, this building and met the shunters in about 1975 ..then of course the place was still fairly busy, with during daytimes coaching stock and parcels vans for such trains as the 1210 Pz/Glasgow, 1445 Pz/Padd, 1806 Pz/Sheffield, TPO, & Slprs plus Cross Country and Paddington coaching sets stabled & cleaned overnight and the attendant spare & crippled coaches & vans and the occasional condemned vehicle too - waiting orders for its last journey for scrapping.
Many thanks for that Tony.