Na stacjach stosuje się zwykle dwie grupy semaforów: wjazdowe (A) i wyjazdowe (B) (czasem również wyjazdowe grupowe C jak na stacji Warszawa Falenica). W obrębie stacji semafor ustawiony jest po prawej stronie toru do którego się odnosi, patrząc w kierunku jazdy.

A stop signal is one that is equipped to show a 'danger' aspect, which commands an approaching train to stop. Its function is to prevent conflict with other trains and to indicate that moveable infrastructure features are in the correct position.
Depending on the manner in which they are used, and the nomenclature favoured by the railway administration concerned, stop signals may be further categorised as 'home signals' or 'starting signals', for example.
Some stop signals are in the form of a fixed signal, generally a white board with a red solid circle. There is usually a panel underneath with instructions to the driver as to what circumstances he may pass the signal. Examples of such signals were used on lines signaled by the radio electronic token block system.