The S&T department, as a semi autonomous entity was allocated their own fleet of wagons which they duly branded as Satlink. Most of their movements would be between the local S&T depots and worksites but complete train movements could be made between regions to, for example, move concrete cable troughs and lids from their point of manufacture. If Civil Link wagons were used they would be airbraked Bass and Skate wagons and would need to be unloaded at the local S&T depot as they would not normally be used to convey materials to the worksite. The S&T were allocated quite a number of vacuum fitted Tube wagons and it was these wagons, often marked as Satlink that would convey materials to the worksite. I can remember, in the eighties, there being a lot of cable laying associated with the various electrification and resignalling schemes in the Anglia region involving an increased flow of troughs and lids. To avoid a lot of double handling and retention of the Bass and Skate fleet under load, a rake of Tube wagons was specially maintained to work between the Northwest and Essex as class 7 vacuum workings.