Dual-mode vehicles able to run on city-centre tram routes and main line tracks have been running successfully in Karlsruhe since 1992. Jean-Paul Masse investigates French National Railways' proposals to introduce the concept to its network

THE IDEA of running trams on suburban railway lines began to circulate in town halls across France about 10 years ago. At that time SNCF was niether technically nor philosophically disposed to accept such a radical concept. Indeed, traditional SNCF culture militated against ideas from outside its own offices.

Despite this, the idea gained ground as pressure grew from various cities keen to make progress with their own plans. A major advantage of through running from main line to city centre tracks is that passengers do not have to change when travelling between suburbs and their places of work or shops. Studies have shown that if there are more than two connections in a journey, customers prefer to use their cars. So dual-mode trams were rightly viewed as a way to attract commuters or shoppers onto public transport.

Technical issues that arise include the development of vehicles able to accept different power supplies, use of wheel profiles suitable for main line and tram tracks, as well as entrance doors able to handle different platform heights.

When Loãk Le Floch-Prigent became President of SNCF in December 1995, local authorities discovered that SNCF was more willing to study the feasibility of running trams on its own tracks. After all, trams would be easier and cheaper to operate than conventional trains on some local routes in the big cities. The concept became known in France as the 'tram-train.'

With Karlsruhe able to look back on several years of successful experience running trams on the then German Federal Railway's main line tracks (RG 11.94 p719), and the arrival of Saarbrücken trams at Sarreguemines station, the tram-train concept began to catch on in France.

Provincial cities are keen

It is hardly surprising that the earliest signs of interest in tram-trains came from a city close to Saarbrücken. Strasbourg was first off the mark with a project that is now being studied by SNCF and the city authorities. The project has three phases.

The first phase covers extension of the existing urban tram network, without any involvement on the part of SNCF.

This will be followed in the second phase by the introduction of tram-trains between Barr, on the line from Sélestat via Molsheim, and Esplanade, which would be reached over an urban tram route. From Esplanade an extension is planned to Kehl in Germany, and then south to Offenburg. This scheme will entail use of both SNCF and DB tracks to create a network totalling 40 km. One problem is the single track bridge over the River Rhine at Kehl, which is a 'temporary' military structure dating from 1945.

In the third stage conventional suburban trains would run from Strasbourg to Herrlisheim, on the line running north to Lauterbourg, and to Erstein, 20 km to the south on the main line to Colmar and Mulhouse.

The Strasbourg project will include a service to Entzheim Airport, and the total cost of infrastructure works is put at Fr1·14bn, with national government and the region paying Fr370m. Funding will also come from the city's Fr475m contract with the European Union that supports what is known as 'Strasbourg ville européenne'.

Strasbourg was soon followed by other cities. Local and regional authorities identified disused or under-utilised lines that could be used for tram corridors. Among cities that expressed interest were Mulhouse, Grenoble, Valenciennes, Saint-Etienne, Rouen, Lyon, Nantes, and Bayonne. Others may join the list in future, including Lille and Orléans.

In Mulhouse, the 56 km network project has a price tag of Fr2·4bn. The scheme provides for tram-trains to run on SNCF track from Kruth, then on-street through the town centre to reach the central station. About 12 vehicles will run under 25 kV and 750V DC catenary, and 16 others will run on the city-owned network only. Today, the Kruth line is used by just 350 passengers/day, but the city hopes that this will rise to 13000 a day once the project is complete.

Grenoble already has two light rail routes and is planning a third, but now it wants to launch a tram-train network by 2004. It plans to use 50 km of SNCF tracks from Voiron or Moirans on the line to Lyon, to reach Vif in the south on the main line to Veynes. A section of the Chambéry line may also be used.

Nantes already has an important SNCF suburban network, but this could be better utilised by creating links with the city's tram network.


In most cases SNCF will provide the tram drivers, but where routes change from SNCF to urban territory local operators will join the driving staff. In some cases these drivers will already work for companies owned by SNCF.

SNCF no longer wants to create a border between areas of driver responsibility, as exists between SNCF and RATP on the Paris RER network, requiring crews to change at Gare du Nord on Line B and Nanterre on Line A. Adopting a flexible approach, SNCF would like to see its drivers handling tram-trains on street-running sections, and in return would allow local operators to provide tram-train drivers who work over SNCF tracks.

SNCF shows the way

Under pressure from local authorities, SNCF wanted to keep the initiative in the tram-train schemes, no doubt to avoid the emergence of projects from would-be private operators. On the other hand, SNCF and the rail unions are always very reluctant to see newcomers sharing their house.

Some time ago, SNCF set up a department known as the Direction du Périurbain to study future projects involving trams running on RFF lines. These studies are now organised jointly by SNCF, Groupement des Autorités Organisatrices de Transport (GART), Union des Transports Publics (UTP), local authorities and interested operators.

In July 2000 SNCF called for expressions of interest for supply of 79 tram-trains, followed by a tender issued on January 24. The first 15 are to be placed as a firm order for delivery by 2004, with options on the remainder. Jean-Claude Degand, Head of the Direction du Périurbain said 'we wish to ease the arrival of these tram-trains and work on the projects with the local authorities; the versions of tram-trains may vary from one city to another'. In mid-February, SNCF received five bids, from Alstom, Bombardier, Matra Transport International, Siemens, Adtranz and Stadler.

It is already clear that the tram-trains will look like any other modern trams. Each vehicle will be able to carry between 200 and 250 passengers; width will vary between 2·40m and 2·65m and length will be 30 m to 40m. Axleload will be 11·5 tonnes to comply with the standards for street running.

Tram-trains running on SNCF tracks will have to be fitted with KVB automatic train protection, the 'crocodile' automatic warning system, as well as data recorders logging speeds and signal aspects. As SNCF's electrified network has areas with 25 kV 50Hz or 1·5 kV DC, the cars may need to accept both voltages, plus 750V DC for street running, and even 15 kV 162/3Hz for the Strasbourg cars running into Germany. Target cost has been set at Fr14m to Fr15m per tram; around 20% to 25% more than a 30m Citadis car as supplied to Montpellier or Lyon, which cost Fr12m.

Paris suburbs

SNCF's first tram-trains will run on the Bondy - Aulnay-sous-Bois suburban line to the east of Paris. SNCF calls this the BA line, but it is popularly known as the ligne des coquetiers (the eggcups line) after the name of one of its stations. Around 270000 people live in the line's catchment area.

The 11 km single-track branch electrified at 25 kV between Esbly and Crécy-la-Chapelle, alongside the Grand Morin valley 36 km east of Paris, is also on the list. Two more trams may be ordered for the Esbly - Crécy line, instead of the four-car stainless steel push-pull suburban set used at present. The trams will provide a more frequent service owing to faster turnaround times. In the longer term, an Esbly - Marne-la-Vallée-Chessy branch may be built, with the trams running in the centre of the road.

The BA line will form a good test route for the tram-train concept. Electrified at 25 kV 50Hz, the 8 km line links the northern and eastern suburban networks. It is double track over the 4 km from Bondy to Gargan and single from there to Aulnay-sous-Bois. The alignment runs mostly along the centre of streets, with fences separating trains from road traffic.

The distances between most stations are very short, less than 1 km in some cases. There are 11 level crossings, and traffic lights at road junctions are interlocked with crossing lights and barriers. Recently, SNCF has spent Fr7m to shorten the waiting time between the gate closure and the arrival of the train to stop impatient people trying to cross the line once the gates are closed - all too often the cause of an accident. There are also some basic pedestrian crossings, with hand-operated gates and no protective warning lights.

At the moment the line is worked by four stainless-steel push-pull trainsets making six intermediate stops. Departures are at quarter-hourly intervals from each terminus, and trains run seven days a week.

Under the tram-train project, two stops will be added, giving 10 stations on the line. Longer term, a branch may be added to reach Montfermeil, a growing and densely-populated town about 10 km east of Gargan, with a tram line built along the centre of a road.

One day, we may even see the trams running to Noisy-le-Sec, to meet RATP's existing Saint-Denis - Bobigny tram route, but it is not yet clear if SNCF trams from Aulnay and Bondy would run on the RATP tram route.

The cost of refurbishing and preparing the line for tram-trains is around Fr250m, with funding shared by the national government, Ile de France region, and SNCF. 'Although in terms of passenger capacity and cost it is less important than the orbital lines around Paris, the Bondy - Aulnay project is SNCF's pilot project for the 12-year plan' (which runs to 2007), says Patrice Leroy, Deputy Manager of SNCF's Direction du Périurbain.