Lima HST Installation
From this
To this
From this
The base plate is sunk into the floor and is flush with the under side of the floor.
Take the XP64/Br Mk II end plates and turn them into the BR Mk III end plates
Note that HST carriages do not have buffers.
For use on radius 1 curves the swing of the draw bar has been extended 1mm on each side by carving away the outer ends of the guide radii
The Mk III Carriage
Unclip the end from the carriage, file off the last section of the existing corridor connection and install the floating end plate. Then do the same to the power cars.
The draw bar has to be modified with two steps in it to pass between the chassis and the tanks.  
The base plate is modified to fit inside the chassis
The slot in the tank is to allow the coupling plate to pass through on instalation.
The Power Car
Coupling Convention
I fit male coupling plates to the locomotives and female coupling plates to both ends of  resaurant
The New Hornby MkIII Carriages.
The Coupling System can be fitted in the same way but it can’t be fitted to the power cars.
fits to
Keen Systems