Twist frames first appeared in 1863 when the Great Western Railway's signal works at Reading strted to produce lever frames. They became standard and gradually became favoured over frames supplied by contractors. There is, of course, a twist in the story when the double twist version appeared in 1890 and became preferred to the single twist version.

Written by one of our members, Alan Price, this paper is key to understanding how twist frame mechanical locking operates. The principles explained are equally valid for other railway company's locking. Modellers who wish to replicate prototype signalling and use it correctly on their layouts also need an understanding of interlocking and this is an excellent reference work on the subject.

This signalling paper is supplied as a photocopied booklet. Copies are created to order - we don't keep piles of them on the shelves - so there can easily be a three week gap between you ordering and the booklet dropping through your letter box. The wait will be worth it!

Need this on a different media? Contact us via the link at the bottom of the page and we'll see what we can do.