living in West Watford in the 1960's, I certainly remember Scammells three wheelers and all their other products! Professionally speaking, I only saw two in service. Both were internal movement only Scarabs, one at KXFT, used by NCL in the Granary and the other at St Neots for moving the NCL fashion flow trailers. Both were still in use in 1980 but I don't know for how long afterwards.
Scamell three wheelers, yes can also remember these in use, we also had a battery driven versions with a coupling which was used for moving trailers about in the warehouse at Hull which was also 3 wheelers and you had to stand up to drive them as there was no seat. just used for internal trailer shunting.
When they was withdrawn some was sold on to fish merchant,s on Grimsby Docks for transporting fish boxes round the docks on there private roads.
Back to station tractors, KX, Liv.St, St Pancras and Paddington at least were equipped in the 1970's with Reliance Mercury four wheel electric tow trucks. They had an 'interesting' electronic control system that could make the truck stand on its rear wheels when you took power. They could also set off on their own.
We had 7, later 8, of these at KX, maintained in the little truck house over the road from the suburban station. Overhauls were done at the ODM workshop in the old steam shed at Hornsey. After FP closed several of their former staff worked at the ODM and Deltic racehorse names started to appear on them!
At Hull we had some very old Greenwood and Batley battery trucks made in Leeds that transported the barrows and later the brutes around the station platforms, they gave very good service and was even used at times with a barrow to act as Father Christmas sleigh pulled by the truck across the station concourse at the opening of the Christmas Tree on the station, a big event in them days with the Lord Mayor carrying out the honour.One still survives preserved in the Transport Museum in High Street in Hull in the railway section.
These was later replaced by some smaller battery trucks.
Grimsby Town station also had one to move the brutes.
Scunthorpe had a second hand Harbuilt electric barrow in later years which came from Chesterfield.
All these items was maintained by the ODM staff in them days and not by a set of outside contractors all taking money outside of the company as is the case these days.
In the mid 1980's they were being superseded by the larger Hamech Ransome type. A couple of these, in grey livery, seem to be still in use at Euston for catering stores work.