Now undergoing trial running at the Siemens test centre in Wegberg-Wildenrath is the first of 15 dual-system Avanto low-floor light rail vehicles ordered by French National Railways in 2002. Harry Hondius reports

Destined to operate on the Aulnay - Bondy line through the eastern suburbs of Paris, which is currently being converted (MR 04 p15), the Avanto LRVs are the first tram-train vehicles to be equipped for operation at 25 kV 50Hz as well as 750V DC. The pre-series car is being extensively tested under both voltages at Wildenrath.

The car is the product of a subassembly philosophy, under which Siemens has developed the concept and subcontracted many major parts as complete modules. The vehicles are being assembled in France, by Lohr Industrie at Duppigheim. Siemens itself is contributing the electrical equipment and bogies. The lower part of the car ends, complete with energy absorption and a built-in retractable coupler, is being supplied by Scharfenberg, the articulations are coming from Hübner and the air-conditioning from Thermo King.

The 2650mm wide cars are 36·4m long, and powered by four 130 kW motors. The concept was described in MR 03 p58, and technical data was given in RG 9.04 (p587).

As well as being the first to be equipped for 25 kV, the SNCF Avanto is also the first genuinely low-floor tram-train, with a floor height of 381mm between the doors. It is also the first multi-articulated tram-train, effectively formed from two 'articulated cars', and it is the first with a crashworthy nose meeting DIN 5560 specifications.

The design has been developed by digital of München, with interior design from Schiefer at Siemens. The heating system is modern, with air blown downwards along the single-glazed windows.

I joined Siemens' engineers on a test run with the pre-series car at the end of April. This took place on the main T1 test ring at Wildenrath, operating anti-clockwise. Ambient temperature was 15íC, with light drizzle and no wind. However, the track is showing signs of wear and corrugation.

At 70 km/h the general noise level inside the car was 67·5dB(A), rising to a peak of 71dB(A) in the articulations. The noise levels were somewhat higher at 100 km/h, reaching 71dB(A) in the low-floor part. The figure reached 77·5dB(A) over the motor bogies, with a peak figure of 81dB(A) during acceleration. There was some external noise from the electronics modules, which could have been quieter.

Some gear vibration was noted at 80 km/h, but the riding qualities were excellent, with high stability along the longitudinal axis. In service the cars will not be expected to run at 100 km/h. For much of the route they will be operating at 50 km/h, with 70 km/h to be permitted for a short distance before each terminus.

Feedback from the tests on the pre-series car, together with ongoing discussions with SNCF, will be incorporated into the remaining 14 cars, where series production is expected to get underway in the second half of 2005. The line is scheduled to re-open in 2006.