INTRO: Harry Hondius reports on the first test trip of this experimental train

LIGHTWEIGHT Regional Express (Lirex) attracted intense interest at InnoTrans in Berlin in September 2000. Described in RG 11.00 p763, this experimental trainset is being developed by Alstom LHB in close collaboration with the Land of Sachsen-Anhalt and DB Regio AG.

The basic thinking behind Lirex was a car body as wide as possible at 3042mm within UIC 505-G2 rules, combined with a 790mm high floor throughout the train.

Steered single Kerf axles (eight for six bodies) were adopted to minimise weight as well as wear and tear, and a proportion of the braking energy could be recovered by flywheel storage. This meant that - for the first time in railcar design - the engines and generator groups had to be located on the roof.

During the first test run at 60 km/h on rather mediocre track, Lirex ran remarkably well. Vibration from the track and from the diesel-generator sets was not perceptible to a passenger, while the noise level, even at full power, was low.

After completing the experimental train, dynamic testing with DB in Minden has commenced. The manufacturer hopes that EBA approval will be secured by mid-2002, allowing the experimental Lirex to enter revenue service in November 2002.

However, significant design changes are being considered, and the series production version will differ in a number of important respects from the experimental unit. As the complete welded-steel train stood on the track, tare weight was much higher than expected. In fact, at 645 kg/m2 of floor area, Lirex fell in the same bracket as Bombardier’s dual-voltage Contessa EMU.

With a full passenger load, this resulted in axleloads of 21 tonnes, which is considered too high by many regional operators. So the thinking on series production indicates a simplified design, with Kerf axles at the ends and conventional articulation bogies between cars.

Three, four, five and six-car units are envisaged, resulting in overall lengths of 47·9, 63·2, 78·4 and 93·7m. By way of comparison, the experimental six-car Lirex is 68·5m long. Because the car body modules will be longer, the width is reduced to 3004mm. However, the specific weight of around 570 kg/m2, if achieved, would be some 13% lighter. Diesel engines would be rated at 480 kW, with one fewer than the number of modules in the unit. Four, six, or eight traction motors would drive the articulation bogies.

We must wait to see whether the present ’privatisation’ climate will allow such a train to be sufficiently developed to achieve success in the end. And there is another question. Will the price be competitive?

CAPTION: Below: The experimental Lirex with roof covers partially removed to show diesel-generator groups, air-conditioning and the Onix-inverters

Below right: Artist’s impression of a simplified six-car Lirex with a floor height of 890mm and seats for 280 passengers