Telegraph block intstrument (permissive)
This image is released under a CC BY-NC-SA 4.0 Licence
Buy this image as a print
BuyLicense this image for commercial use at Science and Society Picture Library
LicenseTelegraph block intstrument (permissive)
Science Museum Group
© The Board of Trustees of the Science Museum
Telegraph block instrument; BR (LNWR-Fletcher's Style). Combined single-needle permissive pegging 3-position/3-indication. Traffolyte-plated "Down Main" and "Chester No 3". Circular bakelite-commutator/permissive tell-tale window is set in a large brass disc. At RHS is 'permissive' plunger and blockbell-tapper is at bottom RHS (door) with underslung bell-dome. Ex. 'Chester No 4' signal box.
