Executing A Massive Signalling Project – Successfully

Siemens is a global leader in the supply of signalling technology and associated rail infrastructure. In South Africa, Siemens Mobility has been contractually involved with the upgrade of the obsolete signalling for PRASA in Gauteng since 2011. Two contracts were awarded to Siemens Mobility to replace the signalling and train control systems in Johannesburg and Pretoria, which included the delivery of SICAS S7 electronic interlocking system, the Gauteng Nerve Centre, ACM 200 Axle Counting Systems and BSG9i Points Machines, among other items.

No one is blind to that fact that the signalling system in South Africa is obsolete and no longer meeting the commuter transport needs of the country. The Gauteng region, probably the most adversely affected, just based on its size and the number of passengers, often makes headlines. Manual authorisation, currently a standard method for train authorisations, in Gauteng anyway, is about to be a thing of the past. To the relief of passengers, PRASA and the Railway Safety Regulator.

At the time of the initial contract, it was noted that the new Railway Signalling System and construction of the Train Control Nerve Centre will enhance operational capacity and allow higher flexibility, improved safety, reduce train delays and remove human error factors.

PRASA set in motion the priority areas for the introduction of the new signalling system in high-volume priority corridors which are; Naledi in Soweto; Pretoria to Johannesburg; Mabopane to Pretoria; Mamelodi to Pretoria.

These type of projects are not only massive from an investment perspective, but they also take time to execute and South Africa has a somewhat complicated regulatory environment which can sometimes lead to delays in implementation.

But, let’s take a step back and appreciate the intricacies involved in this resignalling project, and how it has all come together – through local participation, local manufacturing, skills development, job creation and the expertise required to execute.

Siemens was commissioned to build the new command centre bringing together all the existing control rooms to one location. The Gauteng Nerve Centre (GNC) as it is known, is the core component of South Africa’s largest signalling project, and was built and delivered in just over two years.

Situated on 8,500m² near the Kaalfontein Station, the 3,400m² building serves as the “eye” that overlooks the entire PRASA network. The GNC provides a central location to manage and control the commuter train movement within Gauteng. And, integrates all essential auxiliary services required to efficiently manage train service.

The GNC will provide greater efficiencies in the not-too-distant, future rail operations and train safety while offering a more frequent service through higher line capacity.

The heart of the centre; the command room is equipped with a 52m long video wall used for the monitoring of train movements, the display of the traction electrical supply as well as weather and other operational information. Train movements are controlled from 30 multi-screen workstations each equipped with an integrated communication module consolidating telephone, trunk radio and GSMR communication.

The centre also incorporates; Passenger Information Systems, Overhead Track Equipment monitoring, CCTV monitoring of stations, training room and a crisis control room. Also included are technical room, workshop and maintenance areas, press room, storage of paper and electronic records. The facility is designed to operate 24 hours a day, seven days a week and is equipped with many redundant systems to ensure uninterrupted service.

Two separate electrical supplies, supported by 2 x 800 KVA diesel-powered Rotary uninterrupted power supplies, each able to provide power to the GNC for up to 48hrs. The communications fibre network is fed from a ring system with redundant hardware to minimize network interruption.

The project scope for Siemens Mobility is the design, supply, installation and commissioning of the new electronic interlocking system at 89 stations that will connect to the already built and operational command centre (the Gauteng Nerve Centre).

The project comprises of the modernisation of the signalling system to meet internationally recognised safety levels, and the development of train control software. Both indoor equipment as well as all the trackside signalling equipment will be upgraded to the latest technologies. The outdoor activities include over 500km of trenching and the replacement of cables. The new signals use LED light units which will reduce both maintenance and energy consumption as well as improve visibility of the signals for train drivers.

The completion of the rail signalling project will see the Gauteng railway network aligned to modern urban rail networks seen across the world. The new train protection system will not only increase capacity by the reduction of headways from 15 minutes to 2.5 minutes, but will also provide for bi-directional signalling by enabling trains to “overtake” or pass obstructions that may be blocking one of the lines, thereby ensuring the operator has greater control of the service with the freedom and flexibility needed to reduce train delays.

The system’s safety is also improved with the introduction of axle counters for track vacancy detection instead of the traditional track circuits. For this, the very modern ACM200 axle counting system is combined with the robust and reliable ZPD43 trackside equipment to provide track vacancy information to the interlocking.

The new interlocking makes provision for future upgrades to ETCS Level 2 which is a radio based system that displays signalling and movement authorities in the cab. This system brings two key benefits, firstly it increases safety through automatic train protection feature and, secondly, reduces the trackside equipment.

The heart of the centre; the command room is equipped with a 52m long video wall used for the monitoring of train movements, the display of the traction electrical supply as well as weather and other operational information. Train movements are controlled from 30 multi-screen workstations each equipped with an integrated communication module consolidating telephone, trunk radio and GSMR communication.

The centre also incorporates; Passenger Information Systems, Overhead Track Equipment monitoring, CCTV monitoring of stations, training room and a crisis control room. Also included are technical room, workshop and maintenance areas, press room, storage of paper and electronic records. The facility is designed to operate 24 hours a day, seven days a week and is equipped with many redundant systems to ensure uninterrupted service.

Two separate electrical supplies, supported by 2 x 800 KVA diesel-powered Rotary uninterrupted power supplies, each able to provide power to the GNC for up to 48hrs. The communications fibre network is fed from a ring system with redundant hardware to minimize network interruption.

Siemens Mobility sets out to design and engineer systems that enable safe reliable transport. Each system is designed to achieve a “zero tolerance” approach to incidents caused by the functionality of their systems. Globally, the Siemens teams work seamlessly to assure the safe application of their interlocking system – no, matter where in the world the site happens to be. For the Gauteng Signalling project, the SICAS S7 interlocking has been developed by Siemens within Germany and subjected to stringent EU verification and validation processes to achieve SIL4 certification.

Within South Africa, the local Siemens Mobility team undertakes equipment manufacturing, assembly and all station-specific interlocking design, testing and implementation. Each stage of development in the application of the SICAS S7 interlocking to each station is rigorously and independently checked and confirmed to comply with the relevant requirements.

SIL4 is the highest defined level of safety in the rail industry and has been developed and applied in Europe to run their passenger rail network signalling, including high-speed train operation.

The local engineering team, comprising of 65 employees, is responsible for the design work for all sub-systems in the project. The signalling engineers issue the book of circuits to the manufacturing facility, where every design is station-specific. Software engineers will programme the software required to run the electronic interlocking. Other engineers will design and engineer key sub-systems such as power, network, and the train control system. Finally, test engineers are responsible for ensuring all systems are tested to meet the pre-defined test conditions. All engineering process ensure what is delivered meets the stringent SIL4 requirements.

Manufacturing and assembly activities takes place at the Siemens Mobility factory in Northriding, Randburg. All the equipment required for the SICAS electronic interlocking system makes its way through this factory. Key local suppliers support the factory with materials and components, with some equipment being supplied from Germany due to safety-critical certification. They have been able to reach a 60% local content from a manufacturing perspective and taking labour into account then the total project reaches 70%.

From a productivity perspective, the factory plays an important role in ensuring that there are no bottlenecks on site – so production is always seven stations ahead, which means that if there is a change to site for whatever reason, there is the ability for the project to re-prioritise installation works.

Striving for zero defect, each step is checked and verified before it’s been handed over to the test team. The factory has a staff complement of 28 people, 17 in factory and 11 are part of the installation team.