BS 1745 51st Edition, June 8, 1951
Specification for Alternating-current relays for railway signalling - Track relays (double-element, 2-position) - Line relays (single-element, 2-position)
Includes all amendments and changes through Reaffirmation Notice , December 15, 1980
Additional Comments: W/D NO S/S
Published By:British Standards Institution (BSI)
For circuits not exceeding 250 V. Relays with or without a local element.