Here are some more photographs of the internals of the gearbox.
|Clutch drum and various bits
|Detail of the clutch operating levers
The fast gear clutch connects the input and output gears (1 to 1 ratio). The friction plate is gripped between a fixed plate that is part of the clutch drum and a moving plate connected to one set of operating levers.
|The friction disc with its linings
|Clamping plates either side
|The fast gear friction plate
The brown discolouration of the fast gear friction plate is probably due to oil staining and not due to overheating.
The slow gear clutch shows signs of overheating on various parts. The spindles that operate the clamping plates are also discoloured at a place where they are adjacent to the slow gear clutch. The blue colouring indicates that at some time the steel has been heated to around 290 degrees centigrade.
|Slow gear clamping ring
|Slow gear friction plate and spindles
|The other side of the slow gear friction plate
New Friction Linings
Investigations are ongoing regarding replacement of the friction linings. There is a company in Cumbernauld that undertakes this type of work. In fact they have relined a Ruston 48DS gearbox for a group at Prestongrange Mining Museum.
Another group restoring a 48DS at the Chasewater Railway has also given some useful advice.
It has not been decided yet if riveting or bonding of the friction plates is the best solution.