A tokenless single line block instrument of a type widely used in India in the past. This particular example is *not* from India, but from Crag Hall, UK. It shows the basic features of such block instruments very clearly, including the needle display to indicate the status of the line (train in section, normal, accepted), and the controls to offer a train or accept a train. Photograph from www.tillyweb.biz (signalling equipment photo collection) and used here by permission.