Alstom's latest design of tram-train vehicle builds on its successful modular tram family

LONG-STANDING plans to expand the use of tram-train vehicles in France moved a step further in May, when SNCF placed orders for 31 Citadis-Dualis cars to be used on two projects (RG 6.07 p330), with options for up to 169 more.

Speaking at the UITP congress in Helsinki, Alstom Transport President Philippe Mellier explained how the Citadis Dualis would fit into the company's growing range of modular urban trainsets. At the top end is the Coradia, with a top speed of 180 km/h, for routes with an average distance between stations of 8 km or more. Then come the 160 km/h X'Trapolis and 100 km/h Metropolis EMUs for suburban services stopping more frequently. The Citadis-Dualis is intended to run at up to 100 km/h, compared to 70 km/h for the Citadis tram, and will be suitable for stop spacings ranging from 500 m to 5 km.

Of the 31 vehicles ordered by SNCF, 24 are to be used for the revitalisation of regional railway routes in Rhône-Alpes, radiating from Lyon Saint-Paul station towards Brignais, Saint-Bel and Lozanne. These will be equipped for 1·5 kV and 750 V DC operation.

The other seven will be fitted for 25 kV 50 Hz and 750 V DC, and will run in the Pays-de-la-Loire region, restoring passenger services on the Nantes - Châteaubriand line. However, at present it seems unlikely that these cars will run through onto the city's tram network.

Dualis is a strictly modular partial low-floor car, with all doors in the low-floor sections. It is closely based on the composite modular construction of the existing Citadis family, for which Alstom has so far supplied or received firm orders for no less than 890 vehicles.

Whereas most Citadis cars to date have been built at Aytré, the Dualis concept has been developed by Alstom's Valenciennes plant, with input from Reichshoffen. Conceptual design comes from Avant-Première.

Citadis-Dualis includes some significant advances compared to the earlier design. The newly-developed bogies will have a proper primary suspension and continuous axles. And the cars will be powered by permanent magnet synchronous motors with new IGBT controls, which are lighter than the previous traction package.

The cars will be built to meet the EN15227 crashworthiness requirements for rail vehicle bodies, with a 600 kN buffing load. The cars are also being designed to be fitted with Ertms signalling equipment.

Three lengths are envisaged for the Dualis family: 33, 42 and 51·5 m. These would be carried on four, five and six bogies respectively, of which two, three and four would be driven. Widths of 2 400 and 2 650 mm are proposed. Three dual-system traction packages are envisaged all cars would be equipped for 750 V DC operation, paired with either 25 kV 50 Hz, 1·5 kV DC or a diesel-electric drive.

Each motor bogie would have two 150 kW motors, and the diesel version would be powered by two 375 kW roof-mounted generators.

The initial cars for SNCF will be 42 m long and 2 650 mm wide, with a floor height of 350 mm at the doors ramping up to 395 mm in the saloons and 515 mm above the bogies. The bogies will have 640 mm diameter wheels and a wheelbase of 1 850 mm.

The value of the SNCF contract is €100m, an average of €3·2 m per car, or 28 820 k/m². This is a very competitive price, compared to recent tram-train and LRV orders (MR07 p55). The regions had apparently expected a price of around €4·5 m by comparison the price of a 36·7 m long Avanto for the Mulhouse - Thann line worked out at 45 300 k/m² (MR06 p53). The price is likely to have been based on the full 200-car volume including options. At this price, Citadis-Dualis might clear the way for the revival of tram-train plans that were otherwise at risk of being priced out of the market.

Alstom's previous venture into the tram-train sector was the RegioCitadis car from Salzgitter, which was technically not a part of the Citadis family. Alstom LHB supplied 28 dual-system cars to Regionalbahn Kassel for operation on DB tracks and the city's tram network of these 18 were 600 V DC/15 kV 16 2/3 Hz and the others 600 V DC/diesel-electric. The welded all-steel cars are fitted with non-driven bogies using independent wheels, and received full EBA approval.

Another 54 RegioCitadis cars for 600/750 V DC operation have been delivered for RandstadRail in Den Haag but this is more light rail than tram-train. This German design is now effectively a one-off, although Rostock, Braunschweig, Chemnitz and some Swedish regional operators might still be interested in buying this type.

  • CAPTION: Artist's impression of a four-section Citadis-Dualis car and an interior view showing the powered end module
  • CAPTION: The crashworthy nose module is designed to meet EN15 227 standards
  • CAPTION: A typical 42 m long four-section car, showing the ramps over the bogies and the optional toilet in one end section