Alstom accelerates tram track works thanks to flash butt welding

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The CLEO* project used electric welding on grooved rails for the first time in the construction of a tramway line. Used in conjunction with Appitrack automated track installation technology, Alstom thus offers its customers a practical new solution to accelerate track works and minimise the disruption of city life. 

Alstom owns a new so-called “flash butt” electric welding apparatus specifically designed for grooved rails⁽¹⁾. It was used for the installation of track for the new “East-West” tramway line in the city of Orléans. The mobile welding head – specifically designed to fit the profile of this complex, asymmetric type of rail – is implemented by means of a rail and road machine designed by Alstom.

Applicable to 80% of tramway rail installation situations, this new apparatus designed by Alstom and authorised by the French authorities enables to ultimately produce over seven welds per worker and per day versus 2.5 for the conventional thermite welding process.

Rail welding operations constitute a delicate stage of infrastructure projects because they often require a great deal of time and depend on hard-to-find, highly skilled labour.

So-called “flash butt” welding, previously used only on Vignoles rails⁽²⁾, consists in creating an electric arc between the ends of the rails so that they are welded together without the addition of any exterior material.

(1): Grooved rail is used for the construction of track embedded into a roadway, which is the case for certain segments of urban tramway lines. Its profile is asymmetrical and complex. 

(2): Vignoles rail is used for conventional non-embedded track. Its profile is symmetrical. 

* CLEO: “Construire la ligne Est-Ouest” (Build East-West Line) This new line in Orléans will serve 59,000 inhabitants via 25 stations. A total of 21 Citadis trainsets will circulate over 11.8 km of track, crossing five municipal districts. The CLEO line construction project is the first railway project to combine Appitrack technology and flash butt welding.   

Alstom has experience in building all forms of rail infrastructure