The Ks System

Ks-Signal mit Geschwindigkeitsanzeigern

The Ks system (Kombinationssignal, combination signal) was designed to ultimately replace the West German Hp system and the east German Hl System with a single new one, in connection with the installations of new electronic interlockings.

The Ks signals, like the Hl signals, combine the function of distant and main signals in one single head; that is, they indicate the speed after this signal as well as the speed the next signal will induce.

On top there may be a speed indicator (Zs 3) showing the maximum speed after this signal (in the points zone). Below there may be a speed announcing indicator (Zs 3v) for the maximum speed the signal in advance will impose.

To indicate clear with maximum speed the Zs 3 or Zs 3v will be dark.

There are four main aspects a Ks signal can display:

aspect
Signal ID	Ks 1	Ks 1 + Zs 3v	Ks 2	Hp 0
main indication	line clear*	line clear*	line clear*	stop**
distant indication	line clear	expect reduced speed, which is given by speed announcing indicator Zs 3v below signal	caution - expect stop

*) Speed may be restricted by Zs 3.
**) For rule at signal showing Hp 0 (stop) or at failed signal see also post plates.

Generally speaking, the green light is flashing whenever the speed announcing indicator Zs 3v (the lower sign with the amber number) is lit. The speed is the displayed number multiplied by 10 km/h.

On blocks longer than the braking distance, there may be Ks signals which serve only as distant signals (i.e. they cannot show stop nor impose a speed limit), as well as some which only serve as main signals (i.e. they can show stop and impose a speed limit but don't indicate the following signal's aspect).

If a Ks is used as main signal (i.e. it is capable of displaying Hp 0 (stop), it is identified by a main signal post plate. If it is used as distant-only signal (i.e. it cannot display stop), it is identified by a distant signal post plate. A signal serving both as main and distant indication (a combined signal) has a yellow triangle mounted below the post plate, or it has a white-black-white-black-white post plate.

If a Ks distant signal is closer than braking distance to its main signal, or if it is a distant signal repeater, this is indicated by a small white light. In the case of shorter distance, the white light is to the left above the coloured light, a distant signal repeater is indicated by the white light being at the left below the coloured light.

Note that this white light is only displayed if the driver has to reduce speed (i.e. Ks 1+Zs 3v or Ks 2 is displayed). If the speed stays or increases (Ks 1), a shorter distance or distant signal repeater is not identified (i.e. the white light is off).


Ks distant signal only: Ks 1+Zs 3v: expect 60 km/h	Ks main signal only: Ks1+Zs 3:clear with 120 km/h in points zone	Ks distant signal at caution (expect stop) in reduced distance to main signal: Ks 2	Ks distant signal repeater: expect clear with 60 km/h
	Zusatzsignale (Subsidiary signal) that may be displayed at a Ks signal head (follow links for a detailed description)

Ks combined signal: clear with 80 km/h in points zone, expect 30 km/h	Hp 0+Sh 1 Stop, shunting permitted	Zs 1: May pass failed signal	Zs 7: May pass failed signal, proceed on sight