Point Machines used in UK

[PJW]

Here is the information relating to the old HA and HB machines which is useful to see the evolution of point machines from a motor driving mechanical points to something a little more modern.
The HB manual seems to date from my date of birth; there are still some machines in service, including a few at Reading soon to be eliminated by the remodelling. The HB is clearly the ancestor of the HW machine which is still being installed for new works, albeit that it is no longer preferred for many applications.