The Signalling Diagrams Register is being developed to index a large collection of Signalling Diagrams,
Signalbox Diagrams, Locking Charts, Locking Tables, and other related diagrams, and to integrate the indexing into RailRef.
The register currently contains 5,088
records,
and the whereabouts of 353
individual copies of those diagrams.
Access to the register is restricted as development progresses, and is not ewxpected to be useable until mid-2021.