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Switch-on of the safety installations as a vehicle approaches a level crossing.
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A tram crossing at a secured level crossing.
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Visualisation of the safety installations for level crossings and different route elements such as points, signals, track circuits and barrier drive mechanisms in “Operate & Observe“

Signals for the Extension of Bielefeld‘s StadtBahn

Bielefeld‘s trams started operation over one hundred years ago on 20 December 1900. The line network has been continuously expanded since then. The city’s StadtBahn took off on 28 April 1991 with the opening of the tunnel underneath the downtown area. This year, the StadtBahn celebrates its 25th jubilee. HANNING & KAHL GmbH & Co. KG has now supplied modern signalling technology for maximum safety on the recently completed overground extension.

The network has been growing continuously since 1991, and now has four lines. The most recent extension took place at the end of 2015. The extension of Line 2 from Milse to Altenhagen in Bielefeld was ceremoniously opened on 6 December 2015. The 1.29 km two-track extension connects the Bielefeld suburb of Altenhagen to moBiel GmbH’s tram system. The extension starts at the previous terminal stop in Milse with a 90° bend and a 120-metre bridge across the Lutter stream in the direction of Altenhagen going on to cross the busy Milser Straße and then on via Buschbachtal station to Altenhagen. The crossings on Milser Straße and at Buschbachtal station are now secured by modern signalling technology made by HANNING & KAHL.

Concept
oday, a gated level crossing protects cars and cyclists at Milser Straße. Four semi-barriers, six red/amber signals and four approach/home signals for the tram driver secure the crossing. For further safety integrity, the level crossing is equipped with train protection which is activated from the HANNING & KAHL safety installations for HN-SA level crossings. When completed, the pedestrian crosswalk at Buschbachtal will consist of eight yellow flashing lights and four So10-signals for the driver. Vehicles are detected with HANNING & KAHL block or track circuits of type HSK or HFP. To ensure that only one vehicle crosses the level crossing per direction, blind segment protection was implemented with Drive / Stop signals. The entry signals into the segment are equipped with immobilisers. Both units have interfaces to hand barriers. Milse also has an interface to a traffic computer system. An independent expert certified both units for compliance with BOStrab§21.

 

Technology

 

Vital Processor System Type HN-P
Our vital processor system HN-P which is in successful operation all over the world is also deployed in Bielefeld. This modular system has been specially developed for rail-based public transport and fulfils all the requirements. It complies with safety integrity up to SIL 3; it has an integrated event recorder, signal current monitoring and communication channels for safe communication up to SIL 3.
The HN-P system is in safe and reliable operation on all five continents. Thanks to the widespread distribution of this system, customers everywhere profit from function extensions which may have originally been developed for one particular customer. An example of such a function in this project the interface to train control. A further advantage is that we develop and manufacture all components ourselves at HANNING & KAHL. This way we ensure the long-term availability of spare parts. Yet another plus: The HN-P system works with high and low temperatures without heating or air conditioning – thanks to careful component selection.

Event recorder
Both signalling installations have been equipped with an event recorder which is located on the interface component (IFC). The memory component can be read out via a serial interface or an external reader. All data relating to safety and maintenance is stored in the event recorder. This means that malfunctions (e.g. driver/driving errors, component defects, etc.) can be found swiftly and reliably. In additon, all sequences are protocolled and provide clarification in the event of an incident. The event recorder is synchronised with a radio clock transmitter, doing away with the need for manual setting of the clock upon change-over from and to daylight saving time. All clocks run synchronously in applications with several event recorders. Milse signalling installation also contains the modern diagnostic Event Viewer tool supplied by Verkehrsautomatisierung Berlin GmbH (VAB) which is integrated into the Operate & Observe module.

Operate & Observe
On account of the complexity of the equipment, the safety installations for Milse level crossings were equipped with an industrial PC with a TFT screen for diagnostic purposes. VAB’s VABtrack Operate & Observe module runs on the industrial PC. Operate & Observe means that the signalling technology always has a graphic image of equipment status. It can perform diagnostics quickly and safely in the event of an error and also use the software for maintenance purposes.

Track diagram stagemoBiel secures Buschbachtal crosswalk with a track diagram stage (GBS). The GBS generates the track diagram with the most important control information such as equipment status, occupation of train detection switches and signal status.

Vehicle detection
Best possible solutions can always be devised with HANNING & KAHL’s vehicle detection systems. The bespoke solution can consist of one uniform detection system or of a combination of different HANNING & KAHL systems. In Milse, we use a HFP track circuit system. Track circuit lengths of twelve to 200 metres can be implemented with this system with a wheel shunt detected via the axles smaller than 0.3 Ohm. In double track circuit version, a maximum length of 400 metres is possible. By contrast, Buschbachtal detection switches must be able to implement shorter lengths. So, here, we chose the HANNING & KAHL blocking circuit system HSK. The HSK system is a combination of track circuit and mass detection with which a wheel shunt smaller than 1 Ohm can be detected on lengths between three and twelve metres.

LED signals
Signalling is provided for the tram driver by HANNING & KAHL LED signal transmitters with BOStrab signal aspects. LED signal transmitters have a long service life and emit clear and unambiguous signal aspects, due to the fact that the individual aspects are generated by LED arrangement and not by signal masks. All signals with safety function are current-monitored and fulfil SIL 3. The red / yellow signals for road traffic are also LED signal transmitters of the type found in traffic light applications.

Train protection
For tunnel operation, all vehicles are equipped with ZUB100 (ZUB122) train protection. This system enables automatic train stop and also sends braking and acceleration profiles to the vehicle. Thus the maximum approach speed at Milse level crossing is fixed as is a minimum speed in the event of signal failure in order to guarantee safe operations. All Drive / Stop signals for blind segment protection of the Milse unit have immobilisers. Signal-dependent activation of the coupling coils of the ZUB system is usually direct via special interface components. Because on Milse level crossing, however, level crossing 0/1 signals are flashing signals, the interface components could not be used for this application as they are only designed for static signals. Therefore, the coupling coils are directly activated from HANNING & KAHL’s vital processor system HN-P in this case.

Interfaces
The headquarters of Bielefeld’s Fire and Rescue Station for the north of the city are near Milse. Apart from interfaces to three hand barriers to secure agricultural areas, Milse has a complex parallel interface to the traffic computer system of the city of Bielefeld to enable fire brigade exit at all times. In order not to hinder fire-fighting vehicles with closed barriers, the interface ensures that only those tram runs active at that particular time are processed. No further runs are accepted, and the vehicles are stopped at the signals at Buschbachtal and Milse stations.

Conclusion
With these two signalling solutions, HANNING & KAHL makes a major contribution to this albeit short, but very demanding extension of Bielefeld’s StadtBahn. The flexibility of the HANNING & KAHL team and the technology deployed ensure that in this project, too, all requirements could be met safely and reliably to the satisfaction of our customer moBiel.