block instrument wiring

Over the last few years, I've had a lot of fun figuring out how various block instruments are wired, and connecting them to my absolute block simulator. These pages will help share what I have learned, with other enthusiasts.

I freely admit that my interests lie mainly with the railways of the north of England, so these notes are concerned exclusively with three wire, three position instruments. - especially those from ex-GCR and ex-GNR territory.
To start with, I offer some observations and notes on instruments from the former LNER. These are particularly interesting, as surviving examples allow us to trace the developments of modern block controls.
Some day, I might get round to doing a set of pages for the Midland Railway Rotary Block instruments. Maybe.