South Eastern Railway
locking frame
The South Eastern Railway built its own signal frames at its Angerstein works from as early as 1867. These neat frames featured an unusually short stroke on the lever which made heavy signals and points difficult to work.
The original locking system was a complex arrangement of rockers and shafts behind the frame just below floor level - a system devised by the SE's engineer Francis Brady.
Around 1890, Brady's locking was superseded by a simpler arrangement of tappet locking.
There is no visual difference between the two types, except that the Brady locking examples appear to have been built with the levers spaced at 5" and the tappet ones at 4½". The lever quadrant guides were always separated by wooden inserts.
This example is at Edenbridge, more details of which can be found in the Photo Gallery
London,
Chatham & Dover locking frame
From an early date, the London, Chatham & Dover Railway also made its own locking frames.
These were not totally dissimilar in style to the south Eastern frames - the lever stoke was equally short and awkward, but the quadrant plates were more conventional in being of steel with raised catch guides. The catch block is weighted.
As far as is known, these frames were always interlocked with tappets.
This example is at Canterbury East, more details of which can be found in the Photo Gallery
South Eastern & Chatham locking frame
The South Eastern and Chatham companies merged in 1899, but signalling continued to be managed separately for some while. In 1907, the South Eastern & Chatham introduced a new type of frame which had been jointly designed with Sykes & Co.
The frame featured a much more civilised length of stroke than hitherto, on quadrants with a central strengthening rib almost identical to that found on Saxby & Farmer's Duplex frames. The levers themselves, though, bore no resemblance to that, or any other, design.
The Tappet locking was in an inclined tray below floor level, driven off an ingenious rotating wheel mechanism activated by the lever at the beginning and end of the stroke.
This example is at Canterbury West, more details of which can be found in the Photo Gallery