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The Passenger Rail Agency of South Africa (PRASA) is the country’s largest passenger railway company with 2,300 kilometers of track. This railway network was urgently in need of upgrading and, since 2011 PRASA has earmarked a total of USD $15 billion to improve transport capacity and service quality. The plan involves 7,724 locomotive systems, signal systems in four regions, and wireless communications systems in three regions.
In this project, PRASA planned to construct digital wireless communications systems for railway lines connecting South Africa’s major cities, including Cape Town, Durban, Pretoria, and Johannesburg. The company also wanted to re-engineer signal systems and replace mobile communications systems. The existing mobile communications systems complied with the Ministry of Posts and Telegraph 1327 standard (a signaling protocol standard for analog radio). This system had been operating for nearly 20 years but could no longer deliver secure data communications for railway dispatch systems, other voice services, and new signal systems. PRASA planned to upgrade the communications systems for all of its railway lines over five years, thus building the most-advanced passenger railway system in Africa.
PRASA’s communications system had to cover a large area — 1,200 kilometers of railways with a total of 196 stations. Due to an uneven distribution of existing backbone transmission resources through different regions, the new system had to make economical use of optical fiber resources.
The existing network structures were complex because the networks were constructed in phases over many years. The new system had to interconnect seamlessly with signal systems provided by three different vendors and offer geographical redundancy to ensure reliable railway operations.
Additionally, the new system had to meet the European Train Control System Level 2 (ETCS L2) standard. Therefore, PRASA needed a GSM-R vendor with extensive ETCS L2 delivery experience as well as localized delivery and training capabilities.
Huawei’s communication solution provides softswitch core network products that dramatically improve data transmission efficiency, simplify network management, reduce operating costs, and support smooth evolution from the old system to the new. Distributed base station technology implements quick and flexible GSM-R network coverage in places such as tunnels and crossing lines. In addition, multiple Remote Radio Unit (RRU) co-cell technology was applied to expand cell coverage, reduce cell switchovers, and save a large amount of optical fiber resources.
The solution adopts patented hot-standby mechanisms for all Network Elements (NEs) of the GSM-R network and co-site dual-network technology, coupled with a Synchronous Digital Hierarchy (SDH) network. A Base Station Controller (BSC) was deployed for each of the three regions (occupied by Cape Town, Durban, and Johannesburg) to implement BSC remote disaster recovery. An end-to-end, network-wide redundancy design was implemented to enhance system security and reliability. The Base Transceiver Stations (BTSs) of the access network form a ring topology to protect against faults in transmission links. These measures enable ultra-long-distance network coverage across provinces, ensure reliable railway operations, and facilitate interworking between multi-vendor devices.
In this project, the GSM-R system needed to interconnect with devices from Siemens, Thales, and Bombardier. Fortunately, Huawei had already completed projects in which the company’s networking equipment worked perfectly with the devices of the three vendors.
Similarly, Huawei had successfully delivered ETCS L2-compliant GSM-R communications systems in the Guangzhou-Shenzhen-Hong Long XRL project and the Harbin-Dalian high-speed railway project in China. Huawei’s GSM-R solution has been certified by authoritative third-party organizations such as TÜV, Lloyd’s, and DB. The solution has also passed interoperability tests with multiple vendors of signal and communications systems.
Another advantage lay in Huawei’s local delivery and training capabilities based on the company’s local employees as well as cooperation with local suppliers in South Africa.
The PRASA project marks the first use of ETCS L2-compliant automatic train control systems in Africa. With Huawei’s end-to-end GSM-R system, PRASA can maintain secure and efficient operations and enhance rail transport efficiency. Transport capacity and efficiency from Southampton to Port of Durban has been greatly improved.
The GSM-R system was successfully interconnected with the signaling products of the three vendors. Single-frequency/double-coverage Distributed Base Stations (DBSs), BTS ring, and R4 softswitch core network technologies have helped improve regional railway transport efficiency.