Replacing ageing relay-based signalling equipment with modern electronic interlocking technology on the North Corridor Electronic Interlocking Signalling Renewal project will restore reliable signalling functionality while introducing a distributed control architecture that significantly reduces reliance on extensive copper cabling and centralised equipment.

Launched on August 27, 2026, the new system for the project – owned by State-owned freight operator Transnet – will improve operational reliability, simplify maintenance and enhance resilience amid infrastructure-related disruptions while providing a modern signalling platform capable of supporting the North Corridor’s operational requirements well into the future, says Transnet Rail Infrastructure Manager (TRIM).

The affected section of the corridor has been subjected to repeated cable theft and vandalism, which compromised signalling infrastructure.

“By restoring a modern and reliable train control system, the project improves operational consistency, reduces operational risk and enables more efficient management of train movements,” TRIM explains.

Once Phase 1A and B are complete, the project is expected to restore seven train slots, thereby significantly improving corridor capacity and operational efficiency.

Procurement, detailed design and most of the regulatory approval processes have been completed, with construction and implementation being executed in carefully planned phases to reduce disruption to real-time railway operations.

“As with most brownfield railway projects, maintaining operational continuity while integrating new systems with existing infrastructure remains a key challenge,” says TRIM.

Consequently, the associated risks are being carefully managed through detailed planning, staged implementation and rigorous commissioning processes.

Transnet says with the final testing and commissioning of Phase 1A completed on August 24, 2026, the North Corridor is scheduled for instalment for January 2027.

Dependable Communication

Reliable communication is fundamental to modern railway operations, particularly within a distributed signalling environment.

Therefore, the project will also be equipped with a new fibre-optic communications network that provides reliable and redundant transmission of signalling control data between field equipment and station control systems.

“This modern network largely replaces vulnerable legacy copper communication cables, improving reliability while reducing exposure to cable theft,” TRIM highlights.

The upgraded signalling system also leverages Transnet’s existing fibre-optic backbone, allowing for remote station operation through the centralised traffic control centre while improving operational flexibility across the corridor.

Moreover, the project forms part of the ongoing modernisation of critical rail infrastructure, which supports the Transnet Reinvent for Growth strategy and South Africa’s export competitiveness.

“By replacing obsolete signalling technology with modern systems, the project improves infrastructure availability, operational reliability and network resilience.”

Further, the lessons learned throughout implementation will provide valuable insight for future signalling renewal programmes across the rail network, subject to operational priorities and business requirements, TRIM adds.

The new electronic interlocking system integrates seamlessly with Transnet’s existing operational and maintenance management systems, enabling the organisation to retain established business processes while benefiting from advanced digital capabilities.

The project will also incorporate several complementary technologies, including advanced electronic access-control systems, remote equipment condition monitoring, intelligent power-system supervision and modern fire-detection and -suppression systems.

“Together, these technologies will improve asset visibility, enable faster fault identification and support a more proactive maintenance approach.”

TRIM adds that the technology will not only enhance current operational performance but will also establish a foundation for future digital integration among infrastructure, operational control systems and rolling stock.

As rail technologies continue to evolve, Transnet stresses that this platform will support ongoing innovation, consequently improving efficiency, asset utilisation, operational visibility and the long-term competitiveness of rail transport.

The project represents a major investment in the modernisation, resilience and sustainability of South Africa’s freight rail network, TRIM avers.

“By restoring reliable signalling, introducing modern digital technologies, strengthening communications infrastructure, and enhancing protection against theft and vandalism, the project improves operational performance while supporting increased freight capacity and export competitiveness,” it concludes.

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