Sv System

The Sv system (Signalverbindung, Signal Combination) was created in 1928 as the first German colour light signalling system for the urban railways of Berlin and Hamburg, where it is still used, although it is in the process of being replaced by Ks signals. As with the Hl system and the Ks system, main and distant signal aspects are displayed in a single head.

The main signal aspect is shown on the left half of the signal head, while the right half indicates the aspect the signal in advance will show.

Note that some signals are searchlight type, i.e. instead of a number of differently coloured lamps, rotating colour blends are used to change colours from amber to green; so a signal head may be equipped with just two or three lights, or the red light may be at the low centre. Also the shape of the signal head may vary, sometimes the lower corners are cut off angular.

If the next signal is closer than the usual distance, a white vertical arrow (Bremspfeil, "brake arrow") is displayed. On newer signal heads the white arrow may instead be represented as a dot-matrix bar.

Pictures:	Hamburg Sv surface and tunnel signals
	Berlin Sv and subway signals

These are the aspects an Sv signal may display:


Sv 1: clear, expect clear	Sv 2: clear, expect stop	Sv 3: clear, expect slow	Sv 4: slow, expect clear	Sv 5: slow, expect slow

Sv 6: slow, expect stop	Sv 0: stop, then proceed on sight	Hp 0: (absolute) stop See also post plates	Sv 2, next signal is closer than braking distance	Sv 1, signal positioned to left of track

Some signals are capable of showing Hp 0 (stop) as their most restrictive indication, while others may just be able to indicate Sv 0 (proceed on sight).

The rule for passing a signal showing stop or a failed signal is determined by the signal's post plate.