A turnout signal shows the current position of the assigned turnout . They are designed either as shape signals or as light signals .
With simple turnouts, the shape signals are usually designed as rotatable signal bodies that are either reflective or (inside) illuminated in the dark. The signal body of the light signals, on the other hand, is immobile and has a number of light points that display a different signal image depending on the position of the switch.
Instead of a rotatable signal body, the shape signals of crossing switches often have a stationary signal body with two pointers which indicate the position of the two switch blade groups contained in the crossing switch. It is also rare that a crossing switch has two separate switch signals, as if it were two separate switches.
For some years now, the former Reichsbahn signal Gsp 2 , which can be attached to a track barrier , has also been included in the turnout signals.
Wn 3 - Wn 6 are only available at DKW , here: Wn 3)
Track lock shows Sh 0, after dropping Wn 7
The turnout signal can be read in every direction of travel, but the symbols can differ for the same turnout position for pointed and blunt travel. For example, if a normal turnout is set to “straight branch” , the turnout signal shows a vertical white bar in both directions on a black (or, for fallback turnouts: orange ) background. The same turnout , set on “curved branch” , shows an oblique arrow for a vehicle driving up to a point, which points in the direction of the branching track ; a dull vehicle will see a white circle. In order to be able to interpret the symbols correctly, the driver must of course know whether he is coming from the main track or from the branch.
Turnout signals are mandatory for local and remote turnouts in areas where there are no shunting routes. On the basis of the turnout signals, the driver can recognize an incorrect turnout in good time in order - at low speeds - to be able to bring his train or shunting unit to a stop before the turnout. Remote turnouts that are used without shunting routes occur mainly in older interlocking designs ( mechanical , electromechanical or older relay interlockings ). Since shunting routes are usually available in modern interlockings (relay interlockings, electronic interlockings ), there are hardly any turnout signals to be found in their areas. The exception to this are electrically localized turnouts (EOW), which are all equipped with a turnout signal.
Another exception is the new German railway lines . Although these routes (which have been in operation since 1987) are controlled exclusively by relay and electronic interlockings, a turnout signal was attached to the tongue and frog of turnouts that were passed through quickly. These are mainly used by the maintenance staff, who can thus convince themselves at a glance of the uniform position of the tongue and frog (so-called conformity test ). The signals mechanically linked to the control elements make it possible to check the correct position of the parts, which are sometimes more than 100 meters apart, at a glance, even in pauses of just a few minutes.
- Wn signals on stellwerke.de
- Hoogen: turnout signals . In: Dr. Baron v. Röll (Ed.): Encyclopedia of the Railway System . tape 2 . Berlin, Vienna 1912, p. 315 ff . ( zeno.org ).
- ^ Fengler Wolfgang: Handbook Railway Infrastructure . 2., rework. Edition 2013. Springer Vieweg, Berlin, Heidelberg 2013, ISBN 978-3-642-30020-2 .