Sv signal system

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An Sv signal with a shutter relay (upper two light points) and individual optics (remaining light points) at the exit from Hamburg Hbf

Sv signals are a special form of railway signals that were introduced on the S-Bahn in Berlin and Hamburg and can still only be found in Hamburg today. The term Sv signal represents S ignal v Getting Connected as Sv signals the functions of a main signal and a bias signal summarized in a signal screen.



On the Berlin Stadtbahn , which opened in 1882, the installation of additional block signals between 1889 and 1905 reduced the train sequence to up to two and a half minutes or 24 journeys per hour and direction. The main signals and the route block were operated manually by the signal box staff . The monotonous work steps meant that the staff had to be relieved every one to two hours. With the electrification of the Berlin city, ring and suburban railways decided at the beginning of the 1920s, operations were not only to be accelerated, but the train sequence was also to be denser. Investigations showed that further compaction with the manual block operation would not have been possible. The alternative was a train-controlled signal system that worked with track circuits for track occupation and vacancy detection . The first areas of application for track circuits were found in 1913 on the Berlin elevated and underground railway and in Leipzig Central Station, which opened in 1915 .

When using track circuits, the tracks and points are divided into several sections, and insulating joints separate the sections from one another. Since the running rails also function as return conductors , these joints had to be constructed in such a way that the traction current could overcome them. So-called choke surge transformers, or chokes for short, were used. These transformers each have a low-voltage winding with a center tap through which the traction return current flows bifilarly and thus does not induce any voltage in the high-voltage winding. For the alternating current of the track vacancy detection system, which is fed in or taken from the high-voltage winding of the choke impulse transformer, both parts of the low-voltage winding are in series. The individual block sections each had one or more track circuits. The insulation joints were at the end of the danger point distance of the respective block signal, depending on the maximum speed on the route, this was between 150 and 330 meters.

Since the distant signals were often placed at the location of the main signal on the light rail, it made sense to combine the signal images permanently on one screen. The left side of the signal screen reproduced the main signal aspect, the right side the distant signal aspect. The design designated as Bauart 1928 or Bauart Stadtbahn (AB 28) initially enabled three different signal images, which were displayed by individual optics, so six lamps were necessary (green-green, green-yellow, yellow-yellow; later signals Sv 1 to Sv 3). The yellow-yellow permissive stop signal allowed the train to pass block signals on sight. In front of switches, crossings, platforms or other danger points, a red light for the absolute stop was provided instead of this signal image (later signal Sv 4). The signal box staff released these cover signals manually. In order to ensure that they can drive past quickly in the event of a fault, these signals were equipped with substitute signals (Ad signal, later signal Ve 5). These replaced the former command Ad ("Train no. ... may pass the stop showing ... signal ..."; later command Ab), from which the name originated. As an alternative to the substitute signal, an M-board could also be attached to the signal mast, which allowed the vehicle to pass after verbally instructed by the dispatcher .

The optimal locations for the block signals were determined by means of time-distance diagrams so that the trains were given an understanding of the journey in good time without having to brake. In individual cases, the fact arose that the trains would still have to wait in front of the entry signals from the stations until the train in front had completely cleared the platform, i.e. was behind the exit signal . In these cases, one or two additional signals, so-called follow- up signals, were set up afterwards , which enabled the train in question to approach directly in front of the platform. Since the braking distance was not maintained in this case, the entry and follow-up signals were equipped with brake arrows for identification. In addition, extinguishing contacts were built in that stopped the affected signal immediately after it was driven over and not only when the next insulating joint was passed. If two follow-up signals were set up, both indicated a stop when the platform track was occupied, the first signal automatically changed to yellow-yellow as soon as the train ahead had cleared the platform about halfway.

At Zepernick station in 1927, an Sv signal was mounted on an existing boom as a trial and demonstrated to those responsible at the Deutsche Reichsbahn. In March 1928 the signals were set up on the city tracks of the Stadtbahn between the stations of Charlottenburg and Schlesischer Bahnhof (today: Ostbahnhof). The official commissioning took place on June 1, 1928, eleven days before the start of electrical operation. Sv signals were also set up on the Siemens railway from Jungfernheide to Gartenfeld , which opened the following year . The entry signal e 1 / 2 of the station yard field was already able to signal slow speed and could switch between the signals Yellow-Yellow and Red. It received a total of ten individual lamps. The sections Stettiner Bahnhof (today: Nordbahnhof) - Gesundbrunnen and Schlesischer Bahnhof - Stralau-Rummelsburg (today: Ostkreuz) were also equipped with light rail signals in 1931, and in 1935 the sections Gesundbrunnen - Bornholmer Straße - Schönholz / Pankow .

In the new edition of the Railway Signal Regulations from April 1, 1935, the signals were officially designated as Sv signals and the signal aspects were also added Sv 5 to Sv 8. Until 1952, the terms slow-moving were displayed with two green lamps arranged one above the other, since then with a green over a yellow light.

As early as 1926, the United Railway Signal Works (VES), under the leadership of Siemens, made improvements to the signals. At the beginning of the 1930s, isolated signals were set up that had so-called aperture relays. The relay moves a colored screen between the signal lamp and the lens via a rotating armature and contacts. For a three-aspect signal, only two lanterns were needed. The Ringbahn (later AB 38), introduced in 1938, represented the fortieth stage of development. It was used on the eponymous Berlin Ringbahn and its connecting curves to the Stadtbahn (1938/40), on the Spandau suburban railway to Spandau West (1938; today: Spandau) and used on the Görlitzer suburban railway to Schöneweide (1939), on the Lichterfeld suburban railway to Lichterfelde Süd (1940/43) and in the reconstruction of the suburban railway to Erkner between Ostkreuz and Karlshorst (1947/48).

In the north-south S-Bahn tunnel , which was opened until 1939 , a scaled-down version of the Ringbahn design was used (AB 36/39), which also dispensed with barges . Due to the low speed that was driven in the tunnel, the signals were placed at shortened intervals. The distance on the open route was 250 meters, in front of platforms 100 meters. Signals that were within a shortened braking distance from one another (less than 100 meters) were equipped with switchable brake arrows. Semi-automatic signals were installed at stations with sweeping systems.

Sv signals from Orenstein & Koppel were used on the sections Wannsee - Schlachtensee of the Wannseebahn (1935) and Wannsee - Grunewald - Westkreuz of the Wetzlarer Bahn (1938) . Outwardly, the signals were similar to those of the Stadtbahn type with single lanterns, but the circuits were technically completely different. The lamp circuit was designed in such a way that only one switching contact was required to activate the travel term. The lamps were connected to the three phases of the three-phase network by means of capacitors and chokes in such a way that the lighting up of the lamps for the travel term via the phase shift also caused the stopping term to be canceled. If one of the driving lamps burned out, the stop indicator lit up automatically. The motor of the section stop also took over the function of the block relay, so there was no need for a separate switch cabinet on the signal mast. The chokes and capacitors were installed together with the gear block in the housing of the linear stop drive, which was therefore larger than in the VES systems. A revised version was used on the section of the Wetzlar Railway, which is why small control cabinets for the chokes, fuses, etc. were to be found here.

By 1940, 270.4 kilometers of track or 129.1 kilometers of track were equipped with Sv signals. This corresponded to around 44 percent of the electrified route network with a route length of 292 kilometers. After the Second World War , the signal spacing was increased in many places to enable replacement elsewhere. As a rule, this concerned the expansion of the replacement signals first. The plant for signal and security technology in Berlin (WSSB) presented a further development stage of the Sv signals in 1955. Instead of the substitute signal, the signals could be switched between the terms Sv 4 and Sv 3 for about 60 seconds. The route stop built in to control the train came to a delayed stop after the train had passed , so as not to touch the release lever of the railcars running in the middle of the train. The signals were installed between the Ostkreuz and Lichtenberg stations . With the new edition of the signal book in 1971, the Sv 3 signal was renamed Sv 103, as it was no longer intended for future systems and was to be replaced by the Sv 4 signal in conjunction with the white-black-white-black-white mast sign.

Due to the modernization of the Berlin S-Bahn systems, but also due to the incompatibility of the safety technology of the Berlin Sv signals based on 50 Hz track circuits with the 16.67 Hertz technology of the advancing long-distance railway electrification in the last decades, the Sv -Signs gradually replaced by more powerful Hl signals and Ks signals . The conversion to a supply voltage with a frequency of 42 Hertz, with which the block designs of the S-Bahn would have been compatible with long-distance electrification, was technically possible. Due to the condition of the more than forty-year-old systems and the impossibility of retrofitting a permit change or even driving on the left track without leaving any interference (after driving to the left every second block signal remained in the stop position), it was nevertheless determined that the designs with Sv -Signs in connection with long-distance rail electrification. From 1984 the Sv signals on the light rail in East Berlin were replaced by automatic route blocks of the AB 70S design with HL signals. The light rail in the former West Berlin and the reopened Ringbahn were equipped with the first Ks signals in 1993. The last Sv signals of the Berlin S-Bahn in the north-south tunnel were finally taken out of service in 2006.


From 1944/45, Sv signals of the Ringbahn type were also used on the Hamburg S-Bahn . At the lane plan signal boxes (SpDrS60) in Hamburg, Sv signals are used in a more modern design with an enlarged signal screen on which all signal aspects are displayed via individual lanterns. Exceptions in the Hamburg S-Bahn network are the interlocking areas of Hasselbrook, Barmbek and Poppenbüttel, as well as isolated signals from the "Hhs" interlocking in the main train station, which are still equipped with blend relay technology. In the tunnel area, special signals composed of individual segments in a very compact design are used. Gradually, these will be replaced by Ks signals for new signal boxes.

Signal aspects

The signal images are based on the night signals of the form signals. The signal names differ from each other in Hamburg and Berlin. For Berlin the signal designations are given according to the signal book of the Deutsche Reichsbahn (DV 301), for Hamburg the signal designations according to the signal book of the Deutsche Bundesbahn (DS 301). Since the last Sv signals in Berlin were decommissioned, only the Hamburg names have been used in the DB Netz signal book . It means:

Overview of Sv signals
designation Signal aspect meaning image
DV Sv 1 Two green lights next to each other. Driving at top speed - expect "driving at top speed" Signal Sv 1.jpg
DS Journey! Expect ride.
DV Sv 2 A green light, to the right of it a yellow light at the same height. Travel at top speed - expect "stop" Signal Sv 2.JPG
DS Journey! Expect stop.
DV Sv 3
(Sv 103)
Two yellow lights next to each other. Stop! Pass by and continue without an order! Signal Sv 0.JPG
DS Sv 0 Train stops! Continue on sight.
DV Sv 4 A red light.
If there is a protection signal, two red lights also light up next to each other.
Stop. Sv signal Hp0.JPG
DS Hp 0
DV Sv 4 + Ra 12 A red light.
If there is a protective signal, two white lights also light up, rising to the right.
Shunting allowed. Sv signal Hp0 + Sh1.JPG
DS Hp 0 + Sh 1 Stopping order for shunting trips canceled.
DV Sv 5 A green light on the left;
on the right at the same height a green light and vertically below it a yellow light.
Driving at top speed - expect “driving at speed limit” Signal Sv 3.JPG
DS Sv 3 Journey! Expect slow travel.
DV Sv 6 On the left a green light and vertically below it a yellow light;
on the right at the level of the upper left light a green light.
Driving with a speed limit of 40 km / h - expect "driving at top speed" Signal Sv 4.jpg
DS Sv 4 Slow speed! Expect ride.
DV Sv 7 On the left a green light and vertically below it a yellow light;
to the right of it the same lights at the same height.
Driving with speed limit to 40 km / h - expect "driving with speed limit" Signal Sv 5.JPG
DS Sv 5 Slow speed! Expect slow travel.
DV Sv 8 On the left a green light, vertically below that a yellow light;
on the right at the level of the upper left light a yellow light.
Driving with a speed limit of 40 km / h - expect "stop" Signal Sv 6.JPG
DS Sv 6 Slow speed! Expect stop.


  • Manuel Jacob: 60 years of Sv-Signals . In: Berliner Verkehrsblätter . Issue 1, January 1989.
  • Bernd Kuhlmann: Signal connections. The signal system of the light rail from 1928 . In: Verkehrsgeschichtliche Blätter e. V. (Ed.): Electricity instead of steam! 75 years of the Berlin S-Bahn. The great time of electrification . GVE, Berlin 1999, ISBN 3-89218-275-2 .

Web links

Commons : Sv signals  - collection of images, videos and audio files

Individual evidence

  1. a b c d e f Manuel Jacob: 60 years of Sv signals . In: Berliner Verkehrsblätter . Issue 1, January 1989, p. 2-16 .
  2. a b c d e f g Bernd Kuhlmann: Signal connections. The signal system of the light rail from 1928 . In: Electricity instead of steam! GVE, Berlin 1999, ISBN 3-89218-275-2 , pp. 52-61 .
  3. a b c Wolfgang Kämmerer: The electrical operation on the Berlin S-Bahn. Volume 2.1: The Great Electrification - 1926 to 1930 . VBN Verlag B. Neddermeyer, Berlin 2015, ISBN 978-3-933254-15-3 , pp. 30-33 .
  4. a b c d Steffen Buhr: The signal connections. In: June 5, 2004, accessed May 8, 2007 .
  5. Wolfgang Kämmerer: The electrical operation on the Berlin S-Bahn. Volume 2.1: The Great Electrification - 1926 to 1930 . VBN Verlag B. Neddermeyer, Berlin 2015, ISBN 978-3-933254-15-3 , pp. 138 .
  6. a b c Steffen Buhr: The Sv signal system. In: October 26, 2008, accessed October 16, 2016 .
  7. Wolfgang Kämmerer: The electrical operation on the Berlin S-Bahn. Volume 2.2: The Great Electrification - 1931 to 1936 . VBN Verlag B. Neddermeyer, Berlin 2014, ISBN 978-3-933254-24-5 , p. 82 .
  8. Manuel Jacob: 60 years of Sv signals. Additions . In: Berliner Verkehrsblätter . Issue 12, December 1989, p. 178-181 .
  9. Overview of the main changes to the 1971 edition of the Signalbuch compared to the 1958 edition. Section 2.18 Changes to Section 18. To § 69.
  10. ^ Andreas Janikowski, Jörg Ott: Germany's S-Bahn. History, technology, operations . transpress, Stuttgart 2002, ISBN 3-613-71195-8 .
  11. Michael Braun: Berlin S-Bahn soon without Sv signals . In: signal + wire . tape 98 , no. 3 , 2006, ISSN  0037-4997 , p. 31-34 .
  12. Manuel Jacob: Modification of the last Sv signals in the north-south S-Bahn tunnel. In: October 26, 2008, accessed October 16, 2016 .
  13. ^ Martin Heimann: Signals and signal boxes. In: Retrieved October 16, 2016 .
  14. Ril 301.0101 and 0104, 8th update. December 13, 2015.