See also: recent changes in the Signal Book
An excellent source about the principles of German
railway operations is the
web site of Prof.
An important note: The signals, boards and rules in the western and eastern operations areas of the Deutsche Bahn AG are different for various historical reasons. Where necessary I will refer to the former (West German) Deutsche Bundesbahn [German Federal Railways] as DB, to the former (East German) Deutsche Reichsbahn [German Imperial Railways] as DR.
Both railway organisations do not exist anymore, but since 1994 have been united into the Deutsche Bahn AG (DBAG) [German Railways Inc.], but the differences in the signal systems still persist.
By now the DB and DR Rule Books (Signalbuch DS 301 and DV 301) have been merged and are now called "Richtlinien 301" ("policies 301"), but still the following things need to be kept in mind:
The pages linked to from this page follow a common layout: They have a four-column table, the left column shows the DB (West German) signal aspect ID, the second the DR (East German) signal aspect ID, the third an image of that signal, and the rightmost column contains a description. The only exception is the colour light signals page, where the aspects are listed on separate pages.
Where audible signals are used, they are indicated by equal signs [===] or oh's [ooo] for long or short tones.
Hand signals may be given by hand flag or lantern. I will give the lantern signal where appropriate, because it's easier to represent that as animated GIF.
German railway lines are divided into block sections of different length, varying from some kilometres on the open line to much shorter block lengths within stations. A block section is protected by a main signal. There are also station entrance and exit signals, guarding the station from the open line and the station exit respectively. There is no real difference in the design of block station entrance or exit signals, except that a block signal usually only displays the stop or clear aspects, while station entrance or exit signals may additionally display the 'clear with medium speed' and/or the 'stop for train movements, shunting permitted' aspect where needed.
Also a signal may be accompanied by subsidiary signals, such as speed signals (Zs 3), or speed announcers (Zs 3v), either as fixed boards or illuminated signals.
An Hp System main signal is always preceded by a distant signal, giving an indication of the aspect the main signal will show. These distants are placed at usually between 400 m and 1 km before the main signal, depending on the line speed. Much shorter distances may apply within station limits.
In East Germany's Hl system or with the new Ks signalling system, a single signal head gives the indication for this and the next block, however in both systems there may also appear distant-only and main-only signals.