What do we mean by signaling

Signal control draft

Why a uniform signal control?

It happens again and again that certain operating points are combined with others at meetings, such as branches with train stations or block points. Since the various operating points often have very different controls for the signals, this usually ended in provisional extension cables being made for the individual interlockings. However, dependencies could not be created in this way.

The HI signals typical for signaling at the DR could not yet be controlled properly either. In contrast to form signals, where the main and distant signals are separate signals, here both are combined in one screen. A connection to the following signal is therefore essential for correct control.

Some time ago, various FREMO members discussed the topic. The result was a circuit that was unfortunately not based on the terms to be signaled, but on the direct control of the signal drives or signal lanterns. This means that the implementation of this standard for DB epoch 3 with the form signals or light signals customary at the time is solved quite simply. For other epochs (Ks signals) or state railways, such as the DR, NS or NSB (we also have members from the Netherlands and Norway), things get much more complicated. The technical implementation is also only conditionally suitable. The draft can be found here: http://www.nord-com.net/stefan.bormann/fremo/esig/index.html

How does our control work?

The draft by Martin Balser and me was created in such a way that it was first considered which terms had to be transmitted. By terms, we don't mean the images displayed on the signal, but rather the driver's license and the speed levels. Only after the orientation on the model came the implementation of the model railroad conditions.

Our design assumes that the signal is supplied with a supply voltage from the train station. 16V ~ was consciously taken here, since all possibilities are open with it. No special power supply units are required for this voltage. The normal model railway transformer is sufficient. Both DC voltages of 1.1V ... approx. 20V can be generated, as well as through appropriate rectification +/- Voltages up to approx. 10V each. The voltage is generated by normal voltage regulators of the 78XX series or LM317. Hardly available 10W power Zener diodes or a double structure for both signal positions are not necessary. Only one stabilization is required for all signal aspects.

Direct connection of signals is not provided for with the control via half-waves, which we favor. It is necessary that a relay or optocoupler be used. We assume that the majority of the form signals either have a motor drive, which requires a stabilized voltage, or that the signals have a drive with memory wire. The use of magnetic drives with limit switches (Viessmann) is also possible via a corresponding connection.

The control of light signals of the HI system is basically quite complex, since some speed levels are shown by flashing certain signal lights. A microcontroller can be used to control these signals, since the discrete structure of the circuit is too complex and expensive if too many different signal patterns are used.

For which signal systems is the control intended?

The control should support both form signals and light signals of the Hl or EZMG form and the light signals of the old type of DR. EZMG signals are principally HI signals, but only selected signal terms that are customary for branch lines can be displayed. It is therefore primarily a control that is geared towards the needs of the DR or other member railways of the OSJD, where significantly more signal aspects are common than with the DB.

A "waste product" results from the fact that DB shape signals and DB light signals can also be controlled. Theoretically, it should also be possible to control Ks signals, Sv signals and Sk signals. The control of shape and light signals of the NS or NSB is also quite easy, since sufficient speed levels are available.

Basic information about the DR signal system

The DB uses a signal system that recognizes main and distant signals as well as speed indicators with digits. It just keeps going a Secured section. This system is still used occasionally for the light signals of the DR, as in Magdeburg Hbf. These are relatively old light signals. The signal terms for this are quite similar to those of the DB or the night signals of the form signals.

The DR uses completely different signaling in the HI system. Here it is possible both one, as well as two Secure sections. In the HI signal there is therefore in the upper part of the signal screen the "Distant signal"and below that"Main signal". By means of additional yellow or green light strips and the flashing of the signal lamps, it is possible that different speeds are signaled.

In principle, there are five terms in the HI signal system on "Main signal", or four on"Distant signal":

speedSignal aspect of the main signal partexpected speedSignal image of the distant signal part
100km / hyellow + green light streak100km / h
60km / hyellow + yellow light streak60km / h
40km / hyellow40km / h

This results in a total of 17 sensible combinations of Hl1..Hl13. The distinction between expect 40 km / h and expect 60 km / h is not possible.

The EZMG signaling system shows the same terms as the HI system. However, no light strips are possible, so that instead of the terms for 100 km / h and 60 km / h only 40 km / h is signaled. Since this signaling system imported from the USSR is only used on branch lines in the GDR, the omission of these terms is not particularly annoying.

Further information on the Hl signal system is available on the website of www.stellwerke.de:


We originally had the idea of ​​transmitting the signal aspects over a line with half waves. Of course, this is no longer possible with five terms, since only four states are possible. As an alternative, we planned that one line would convey the concept of travel or stop and a second line the speed. In addition there is 16V alternating voltage, one pole of which represents the return conductor for the first two lines. So it was possible in the simplest version to get by with four cores.

In practice, however, it has been shown that it makes more sense to assign the lines differently. Since decoding with a minimum of electronics is necessary anyway, Martin Balser has optimized the assignment in such a way that the decoding effort for the HI signal is minimized.

Since almost every train station has a 16V AC voltage supply, the generation of the half-wave voltage should not be a problem. The decoding of the signal can also be done quite easily with diodes and relays or optocouplers. The system also contains signals that we will not need for the time being. Still, we included it as an option. It is easier to take these things into account now than to tinker with the control later because certain things have been added. We have also included the maneuvering signals because in new buildings it makes sense to use the same control for entry and exit signals in order to be able to freely exchange plug-in signals.

It is somewhat problematic that HI signals can represent both the signaling for one section or also two sections. This means that an exit signal can indicate, for example, "drive at Vmax at the next signal", although the next main signal may show H133. If the next signal is a single distant signal, this signaling, which at first glance appears illogical, makes sense. At the distant signal (next signal!) You can finally drive past with Vmax. Only there one learns that the main signal shows HI13 (stop)...

This problem has yet to be resolved. One approach to this would be to lay lines between the stations. Then one could achieve through a clever wiring that it is recognized whether the next signal is a main or distant signal. It is important that there is potential separation to ensure that the AC voltage sources are not connected in parallel.

Line assignments

The voltage source is the usual model railway transformer with 14-16 VAC. The 16V AC voltage is used to generate the voltages required for the drives or lamps. With + or. - the positive or negative half-wave is meant. +/- means alternating voltage.

The 8-pin RJ-45 connector is assigned as follows:

Veintransmitted signal aspect of the respective line
1 bluefree (reply later)
2 orange+ Slow speed, - Speed ​​indicator 80km / h or 100km / h
3 black+ Ride with Vmax, - Speed ​​indicator 60km / h
4 red16 V AC
5 greenDimensions
6 yellow+ Stop!, - Substitute signal
7 brown+ Shunting permit, - Speed ​​indicator 30km / h
8 whitefree (later tension)

Fig. 1: Assignment of colors and pins (view of the opening of the socket)

This results in the following frequently used signal aspects when combining the lines:

Line 2Line 3Line 6Line 7Term displayed on the signal
 Stop + substitute signal
Stop + maneuvering permission
Halt + form signal Zs3 (3) or Zs106 pulled
Slow travel 30 km / h or early stop (stump track)
   Slow travel 40 km / h
  Slow travel 60 km / h
  Slow travel 80 km / h or 100 km / h
  Travel Vmax
    Emergency red (optional)

Lines without entering the polarity are voltage-free.

Additional signals

At the moment, track change indicators, direction indicators and the wrong-way order signal are not yet included in the lines, as these are relatively rare under our conditions.

According to our first draft, it would be conceivable to control this signal as follows:

Line A (optional)

  • positive half-wave = Zs4 direction indicator possibility 1
  • negative half-wave = Zs4 direction indicator possibility 2
  • AC voltage = Zs4 direction indicator option 3
  • no voltage = Zs4 direction indicator option off
Line B (optional)
  • positive half-wave = Zs7 track change indicator /
  • negative half wave = Zs7 track change indicator \
  • AC voltage = Zs8 wrong-way travel order signal
  • no voltage = Zs7 track change indicator off
The supply voltage is again the alternating voltage applied to wires 4 and 5.

Which connector system is used?

8-pin Western plug connections are used.

Connection of certain signals

  • HI signals
  • EZMG signals
  • HV signals
  • Form signal with motor drive
  • Form signal with magnetic drive
There are currently no electronic circuit diagrams.

Are there any operating points that use this control?

There are options to use this control for the Vossbergen junction and the Storkow station. At my Mühlenroda station, which is currently under construction, EZMG signals are installed, which are also controlled in this way.

The Wutha block post has hi signals. Since this block point has already been used several times together with branch points from other module owners, the connection of the signals to this system is converted to facilitate the connection.

It would also be conceivable to use this electrical system in the signal shafts of the "Wattenscheid" type, which are built into numerous line modules.

Links to the signal shafts



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Authors of this page: Armin Mühl, Martin Balser