Sv System

Sv-Signal  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. 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, 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 is displayed. On newer signal heads the white arrow may 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  Sv 2  Sv 3  Sv 4  Sv 5 
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  Sv 0  Hp 0  Bremspfeil 


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 a signal showing Hp 0-stop or at a failed signal is determined by the signal's post plate.