What we do


Conventional lines, high speed lines, metros and tramways… TSO is able to deploy a wide range of skills, from design all the way through to commissioning

High Speed lines

High Speed Line Track Construction - SEA Railway Line

TSO has contributed to laying more than 2,500 km of high-speed rail lines in France and in the UK.

Conventional lines

Restoration of rail traffic between Oloron and Bedous

TSO has delivered many successful projects in France and abroad. Multi-gauge track, meter gauge track, heavy haul track, etc.

Urban lines

Crossrail Tunnel - Track Construction on urban line
Lightrail - Tramway in Luxembourg
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TSO tailors its service offer to meet the needs of all urban transit systems, from trolleybuses to tramways, subways and commuter trains. Permanent way, third rail, conventional overhead line and rigid catenary. TSO teams are currently delivering Crossrail rail systems package in London.


Renewal and upgrading of existing lines

Railway Renewal Worksite in France

Renewal works cover all the major maintenance operations for track, switches and crossings, and catenaries. These maintenance activities may be carried out in parallel with upgrading works, such as track realignment for operating speed increase, relocation of switches and crossings, longitudinal profile lowering for electrification.

Rail replacement

The “BOA” Train

Railway Renewal and Maintenance Plant

A patented methodology enables all the operations involved in supplying, replacing and releasing new rails at the sustained rate of 300 meters per hour to replace Long-Welded Rails using just two electric welds every 25 minutes. Used as standard for high speed lines, the BOA assembly-line train was brought into the Paris urban network lines for the first time to lay 20 km of track for Line E between Chelles and Noisy-le-Sec.

Replacement of switches and crossings

TSO is contracted to replace an average of 200 switches and crossings per year for SNCF Network over a 5-year period. The nature of the work involved requires the introduction of a special dedicated organizational structure called SMA: ‘Suite Mécanisée d’Appareils de voie’ (Mechanized Continuous S2C’s Replacement)

High output plain line renewal

Replacement by high output operations ‘High output sequences of operation’ makes it possible to replace every part of the old rail track without suspending operations on the line. It is effectively a mobile worksite through which a succession of work trains pass to replace an average of 1 km of track

Track rehabilitation in confined areas

This type of project involves renewing the ballast, rails and sleepers of ‘challenging’ sections of track (platforms, tunnels, cuttings, tight curves, obstacles, etc.). TSO uses PUMA 2 and DRL-C machines to carry out this type of work using a methodology unique in France. Upgrading of temporarily non operated lines This type of project involves replacing the track (ballast, rails and sleepers), carrying out civil engineering work (linear drains, ditches, platforms and engineered structures) and ensuring rail safety (road crossing operator, train operation, formation of track maintenance trains, etc.).


OLE Renewal Worksite - Railway Projects

TSO, an expert in the electrification of railway infrastructure, can provide you with appropriate answers to complex requirements. Our teams are focused on delivering turnkey projects and helping you with your electrification and remodelling projects.

We have a dedicated project team to ensure the proper delivery of our projects. TSO offers to all its customers a short decision-making process, appropriate answers and resource optimisation.

Our range of services include electrification of new lines (conventional and high speed), remodelling and maintenance, project planning, principle and basic design, detailed design etc. Our teams are committed to deliver projects with safety at the core of our priorities. Whether it’s overhead contact systems or rigid overhead conductors, TSO is ready to take on your challenge.


Railway worker working on survey on trackside

In addition to high level site surveys, TSO uses a 3D scanner & GPS to create a point cloud of the surveyed infrastructure. Following the survey the cloud point file is combined in the office to allow further analysis. This takes advantage of the limited access to railway and avoids the need to return to site in case any information is missing.

From these cloud points and with the use of pictures and historical records (when available) we are able to reproduce in detail OLE structures or create and surface model of the civil asset surrounding the OLE structure (overbridge, retaining wall etc.).

3D surveys also allow us to undertake a clearance and gauging exercise when records are missing or inaccurate.