Britain has completed the world’s first mainline trial of quantum inertial navigation technology, testing a system that determines train position without satellite signals. The Rail Quantum Inertial Navigation System was trialled on Govia Thameslink Railway services between central London and Welwyn Garden City, providing real-world performance data in a live operational environment. The technology uses ultra-sensitive sensors to detect motion and rotation changes, enabling precise positioning in tunnels and areas where GPS signals are unavailable or disrupted. Developed by a consortium including MoniRail Ltd, Imperial College London and QinetiQ, the system could replace costly trackside positioning infrastructure while enhancing network reliability and resilience.

Britain’s railway has taken a significant step forward in the development of quantum navigation technology, with a new system designed to measure train position with high precision now tested on the national network.

Quantum inertial navigation uses ultra sensitive sensors to detect small changes in motion and rotation, allowing trains to determine their position without relying on satellite signals. Unlike GPS, the system can operate in tunnels, dense infrastructure or areas affected by interference, offering a more resilient alternative to existing positioning methods.

First mainline trial of quantum positioning

The Rail Quantum Inertial Navigation System was recently tested on a mainline service operated by Govia Thameslink Railway between central London and Welwyn Garden City. The trial provided real world data on system performance within a live railway environment, marking the first time this technology has been tested on a mainline anywhere in the world.

The technology is being explored as a potential replacement for fixed trackside positioning infrastructure, which can be expensive to install and maintain and may be vulnerable to disruption or failure. A successful rollout could reduce costs while improving operational reliability and resilience.

The programme builds on earlier work by the Ministry of Defence and Transport for London, extending quantum sensing research into heavy rail applications.

Development is being led by a consortium including MoniRail Ltd, Imperial College London, University of Sussex, QinetiQ, PA Consulting and National Physical Laboratory, with support from Innovate UK and the Department for Science, Innovation and Technology.

The initiative is coordinated by GBRX to accelerate adoption of emerging technologies across the rail network.

Rail Minister Peter Hendy said the development continues the UK’s legacy of rail innovation and will help improve reliability and passenger experience.

Toufic Machnouk of GBRX added that quantum sensing could reshape railway operations by reducing reliance on trackside systems and enabling smarter, more efficient networks.

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