Commissioning tests with a deadlock scenario on the Zwickau Stadthalle side - photo: Dr. Steffen Schranil
RegioShuttle 650 072 as RB 2 Bad Brambach north of Zwickau Stadthalle within the signalling installation, point signal A2 and Planitzer Straße secured level crossing in the background - photo: Dr. Steffen Schranil

Rapid Transport to the Centre of Zwickau: Signalling Installation with Tram Control

tramnews: Dr. Schranil, what is behind the ‘Zwickau model’?

Dr. Schranil: The Zwickau model enables direct connections between the centre of Zwickau and the surrounding area. Technically speaking, this means connecting train and tram as a tram-train system using a dual-gauge track since the Zwickau tram has a narrower gauge of 1,000 millimetres. Special to Zwickau, trains run on the tram infrastructure.

tram.news: For us, you personally stand for the ambitious technical modernisation of the Zwickau model. What projects did you have to handle for this?

Dr. Schranil: Since the commissioning of the standard gauge on 28/05/1999 and the metre gauge on 01/10/1999 the daily traffic left clear traces on the infrastructure. After more than twenty years of use, three specific modernisation works were then on the horizon from the end of 2019 to enable long-term stable tram-train operation:

  • Modernisation of the control system in the dual-gauge track (start of operation 13/06/2021)
  • Basic repair of the special points in Zwickau Zentrum (start of operation of the metre gauge 29/10/2022, standard gauge 11/12/2022) and Zwickau Stadthalle (start of operation 07/2023)
  • Construction of a signalling installation with tram control (preliminary operation from 08/10/2022 / start of operation 11/12/2022).

We reported on the control system project and the new technical network access in TRAM News
No. 98 (09/2021).

tram.news: Can you briefly explain the current signalling installation with tram control project?

Dr. Schranil: The single track section 9705 between Zwickau (Sachs) main station and Zwickau Stadthalle was previously protected by a train protection system with block system. The associated safety technology was in acute danger of obsolescence. Therefore, a short-term solution had to be found, integrated into the adjacent control and safety systems of DB Netz and already be future-compatible with the Zwickau electronic interlocking from the end of the decade.

Most recently, the rail vehicles in the section in question were running at 30 km/h for operational reasons although the infrastructure was dimensioned for significantly higher speeds. According to the analysis of what is operationally desirable and technically feasible the new maximum speed is
60 km/h. This still allows for running at sight and the use of a signalling installation. A train control system was added to trigger emergency braking in the event of a vehicle unexpectedly approaching the signalling installation or the crossing of an F0 signal.

The preferred variant developed by the SVZ separates the functionalities of securing the single track as a signalling installation according to the German Federal Regulations on the Construction and Operation of Light Rail Transit Systems BO Strab from that of the entry and exit to Zwickau (Sachs) main station as a train route according to the Railway Construction and Operating Regulations (EBO). The Planitzer Straße level crossing operates largely autonomously within the signalling installation. When a rail vehicle approaches the signalling installation the safe activation checks that the axle counting circuits are free, the position of the A2 points and its setting are correct and the level crossing has been triggered. Since the level crossing is switched off via separate axle counters immediately after it has been crossed this results in very short closing times.

The costs of the formal municipal project were about €0.80 million and it was co-financed by tax funds based on the budget passed by the members of the Saxon State Parliament (75%) as well as the city of Zwickau's own funds.

tram.news: How did you find H&K as a partner and how was the cooperation?

Dr. Schranil: After the planning phase we published a call for tender for the delivery and installation in accordance with the contracting rules for award of public works (VOB) throughout Germany on 10/12/2021. H&K applied for it with Frauscher Sensor Technology as well as Scheidt & Bachmann for the level crossing control. The contract was awarded on 21/03/2022 with an initial target of six weeks of implementation by 26/08/2022. This schedule was discarded in consideration of the project planning and delivery deadlines.

The dismantling of the existing system started on 29/08/2022 together with the first construction phase of the special points, which was postponed for this purpose. At the same time the new signals were installed, the control system for the Planitzer Straße level crossing was renewed, and deconstruction work was carried out by DB Netz. On 08/10/2022, the provisional operation from Zwickau (Sachs) main station initially to Zwickau Stadthalle was started, which only included activating the level crossing via auxiliary switch-on buttons. On 22/11/2022, the factory acceptance of the signalling installation took place at H&K. Commissioning was performed on 09/12/2022, so that from 11/12/2022 all trains again reached the centre of Zwickau according to the new timetable.

It must be stated that despite the short implementation period H&K found a customised solution which enables safety and availability of vehicle operations in the non-standardised interface of BO Strab and Railway Construction and Operating Regulations (EBO).

tram.news: That sounds like close coordination with DB Netz and the Technical Supervisory Authority (TAB). What was your experience in this regard and since then?

Dr. Schranil: For the transition from the EBO to the BO Strab mode of operation, DB Netz successfully went through a company-internal approval process (UIG). This implies e.g. that in terms of safety the EBO starts within the BO Strab route to prevent conflicting vehicle movements in the direction of Zwickau (Sachs) main station.

A regular approval procedure in accordance with the BO Strab was required. For commissioning approval, the SVZ was responsible for the technical management vis-à-vis the TAB, including the test program to be created and executed. The railway supervisory authority came to Zwickau for on-site  inspections after the start of preliminary operation and after the start of regular operation. On 27/03/2023, the commissioning approval according to Section 62(6) BO Strab was granted without conditions.

After about half a year with the new technology and the associated new operating modes the experience to date has been very positive. While the first runs to the centre of Zwickau were still personally accompanied by the operations manager, today the positive feedback of the drivers and dispatchers prevails. The processes have become established and availability remains stable at a very high level.

The interview was conducted by Jörg Grote, Account Management, Infrastructure Division

Short CV

Dr. Steffen Schranil, 38, is a traffic engineer for electric railways (TU Dresden) with a doctorate in railway operations research (ETH Zurich). Initially, he worked as a sub-program manager at SBB Energie, fleet manager at SBB Cargo International and head of ATO at Stadler. In Saxony, he has been employed as head of the technology department of Städtische Verkehrsbetriebe Zwickau (SVZ) since 11/2019, and was appointed as BO Strab operations manager in 05/2022.