During the 1960s in Scotland, BR created the Glasgow Parcels Depot in Salkeld Street, according to the carriage working books of the day, any train heading towards Glasgow Buchanan Street or Queen Street that had any parcels vans in the consist had them removed at Stirling or Perth, these were then combined to form a parcels train that would run via Coatbridge and Rutherglen to Shields Junction for reversal into the depot, The 1964 Carriage working book is fascinating and there are BGs being transferred from one service to another at almost every major station. The last real marshalling of any mail working was the West Coast Postal at Carstairs, where four vans were added from Aberdeen and a single BG added from Edinburgh, often hauled by a class 87, how is this for an over powered parcels service!!
Jim