Block signals provide up to 6 track occupancy aspects, and provide indications for 3 speeds in the main signal head. Additional speeds are signaled by supplementary heads, as are directional indications.
French railways have an extremely diverse history of mechanical signals.
The night aspects were provided by spectacles in the face of the boards turning a lamp the proper color. When the signal rotated to edge-on, the white light was visible for the clear indication. Semaphores were also occasionally used for mechanical signals, notably for a permissive stop indication, and in stacks for route indication. Later the lamps were moved below the signal board to form assemblies of colorlights which corresponded to more than one mechanical board when installed in clusters. In the early 1930's, colorlight signals were experimented with, originally corresponding to the 1885 code and other individual railroad practise.