DMT ensures the precise alignment of the tunnel route during the construction of the new metro line in Cairo using the world’s most accurate survey gyroscope

Essen/Cairo, 10 February 2026 – DMT, a company within the TÜV NORD GROUP, is undertaking the high-precision surveying of two metro tunnels in the Egyptian capital as part of the construction of the new Cairo Metro Line 4. The aim is to ensure the exact alignment of the tunnel tubes between Cairo city centre and the Grand Egyptian Museum on the west bank of the Nile – a key prerequisite for reliable and safe metro operations.

Cairo Metro Line 4 is one of the most important infrastructure projects for the future development of transport in the Cairo metropolitan area. The new line is intended to link heavily frequented urban areas, relieve pressure on private transport and significantly increase the capacity of the local public transport system. The direct connection to the Grand Egyptian Museum also provides one of the country’s most significant cultural projects with an efficient link to the urban transport network.

DMT is responsible for monitoring the geodetic alignment of the two tunnel tubes over a distance of almost 19 kilometres. The surveying work is carried out in parallel with the tunnelling operations and ensures that the planned route is adhered to with the utmost precision, even underground. Precise tunnel surveying forms the basis for safety, operational efficiency and the long-term availability of the infrastructure.

“The expansion of high-capacity transport infrastructure is a key prerequisite for meeting the rising demand for mobility in growing metropolitan regions. With the help of our experts and our high-precision on-site surveying technology, we are helping to lay the foundations for safe and permanently stable operation,” says Jens-Peter Lux, Managing Director of DMT and Head of the Infrastructure & Raw Materials division at the TÜV NORD GROUP’s Energy & Resources Business Unit.

For geodetic monitoring of tunnel excavation, DMT uses the Gyromat – the world’s most precise surveying gyroscope. The system continuously provides highly accurate direction and position data and enables ongoing monitoring of the tunnel’s alignment underground. Deviations from the planned alignment can thus be detected at an early stage and compensated for through structural engineering measures.

In addition, DMT provides support in establishing a higher-level geodetic reference network based on satellite-based GNSS measurements, precisely coordinated control points and geodetic traverse lines. Particular attention is paid to the combined processing of the various measurement data. This reference system forms the basis for all subsequent surveying work – from control surveys and centreline staking-out to the coordination between above-ground planning and underground tunnelling.

“As tunnel length increases, the demands on geodetic control rise considerably, as even the smallest measurement deviations can add up over the course of the tunnel,” explains Benedikt Wolters, Senior Surveying Engineer at DMT. “With the help of the Gyromat, we achieve maximum drilling accuracy. Our aim is to monitor the tunnelling process in such a way that deviations are detected at an early stage and the construction work is supported in a targeted manner.”

DMT brings to the project expertise gained from hundreds of international tunnel and metro construction projects. The combination of decades of experience, high-precision measurement technology and a clear focus on quality, safety and precision forms the basis for reliable project delivery, with the aim of creating a modern and sustainable transport infrastructure for the rapidly growing Cairo metropolitan area.