Publié le 23/02/2016 - Mis à jour le 17/03/2016
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The Grand Network Modernisation Plan: preparing for rising demand

The Grand Network Modernisation Plan (GPMR) is a priority project for SNCF Réseau, with an investment budget of more than EUR2.5 million per year. Limiting service disruptions by defining the best possible works organisation, as far in advance as possible, is no small challenge. Thanks to rigorous planning and digital technology, not to mention the efforts of thousands of people, that challenge is being met!

In the Midi-Pyrénées region, a regional passenger train streams through the countryside of southwest France  under the the winter sun. One of its passengers is Brigitte, 60-ish, with the sing-song accent typical of the area. She is on her way to Albi for some Christmas shopping. “I know exactly which shops I will be going to because I don’t want to miss the return train at 15.20 to pick up my granddaughter at school!” But the smiling retiree is not really worried: since automated signal systems were installed between Tessonnières and Albi, unscheduled stops in mid-track have become a fast-fading memory, and the trains rarely run late.

Planning for efficiency

“Building new computer-based interlockings and a remote control centre guarantees streamlined traffic management and is therefore the key to better regularity”, confirms Selim, a Functional  Manager at SNCF Réseau’s Information Systems Department. From his Parisian office, thie engineer explains the decisive role of information technology in the modern railroad sector. “It is an invaluable management-support tool”, he says. “Information technology gives us increasingly detailed knowledge of what’s going on in the network and enables us to intervene with maximum efficiency.”

Building new computer-based interlockings guarantee streamlined traffic management

A few hundred kilometres away, the Saint-Martin-d'Estréaux Tunnel carries the small regional line across the Forez Mountains. Sophie is in charge of heritage studies at SNCF Réseau. Armed with her electric torch and accompanied by a works manager from SNCF, she inspects the tunnel, which is scheduled for a complete renovation to improve the service between Lyon and Clermont-Ferrand. “This line does not handle an extremely high number of passengers, but the works are necessary for safety reasons,” the young woman explains. “You must remember that half of our civil engineering structures are more than a hundred years old, and that is especially true here in the birthplace of the French railroads!”

Digital technology for ever-better reliability

Back in Selim’s office, the engineer explains, “Every day, almost 15,000 trains run on the 30,000 kilometres of our network. Here in the Paris region, the frequency is especially high. Just think: the suburban commuter line RER A has three times as much traffic as the TGV high-speed system! For the suburban RER B line, the trains run every 3 minutes at peak hours! Under those conditions, it is impossible to predict incidents, but we can anticipate the conditions in which they occur. And we do everything in our power to do so.


Vue de RER à quai


Every day, almost 15,000 trains run on the 30,000 kilometres of our network

This is precisely the idea behind the deployment of GSM-Rail. Discussions about network reliability and renovation tend to bring “works” to mind. But management systems also play a critical part. Replacing an analogue technology with a digital technology will enhance reliability, and the dedicated frequencies used for transmissions between trains and railway regulation centres allow greater responsiveness when incidents do occur.”


GSM-Railis a new telecoms system tailored specifically to railways. The existing Ground-to-Train  analogue radio system is being phased out and replaced with GSM-R. When fully deployed, GSM-Rail will enable digital voice and data communications over the 15,000 km of the main line network. It is being developed by a public-private partnership and with interoperability at the European scale.

A colossal project with little impact on traffic

A few dozen kilometres farther north of Paris in the Oise  Valley, works are in progress. Every day, 28 passenger trains and 6 freight trains use the Tergnier-Laon line, the link between the Picardie and Champagne-Ardenne regions. Arnaud, a maintenance and operations technician for SNCF, is busy working a lag-bolter. Putting the rail clips back on the new ties is one of his tasks in connection with several weeks of renovation works on this 37-km section of track. “After completing the preliminary works, we are now in the process of replacing the rails, the ballast and the ties. The job will take a total of six months including the finishing works. There are about 400 of us assigned to this project, which involves placing more than 40,000 tonnes of ballast and 34,000 ties.”

Why renovate the track?

When it comes to a track renovation project, who’s who? Why is this such a necessary task? And how often does it take place? How are the works carried out? This video has the answers.


The project represents an overall investment of EUR37.1 million, which is being completely funded by SNCF Réseau. When it comes to passenger safety and comfort, no price is too high! The works become necessary due to the natural wear and tear of the materials, but they do not stop the trains from running. An appropriate transport timetable is implemented because passenger safety and comfort go hand in hand with punctuality.