ZAGRO Unimog U 423 road-rail work vehicle for Graz tram lines

Holding Graz Linien in Austria decided in favour of a ZAGRO road-rail Unimog U 423. The vehicle is used to maintain the tramway network in Graz. The basic Unimog U 423 vehicle had to go through several production stages before it was converted into a road-rail vehicle for work.

After factory production at Daimler, the Unimog U 423 with a wheelbase of 3600 mm was given an extension of the frame overhang from the centre of the rear axle to the end of the vehicle to approx. 2600 mm. The vehicle was then taken to ZAGRO Bahn- und Baumaschinen GmbH in Bad Rappenau-Grombach, Germany. Here, the Unimog was fitted with a type 407 rail guidance system, the so-called bogie-type rail guidance system. This type of rail guide is particularly suitable for use on tram lines, as it can be used to negotiate tight curve radii of up to 17 metres.

The vehicle was also fitted with railway-specific equipment by ZAGRO. In addition to the SIFA safety driving circuit, signalling light system in accordance with BOStrab, fire alarm and extinguishing system, shunting mirrors, cameras as a rerailing aid and lighting for the rail guide were installed. The road-rail vehicle can now run safely on tracks with a track gauge of 1435 mm. Without the coupling rod, the road-rail Unimog has a length of approx. 7.9 metres.

The road-rail Unimog then travelled to Denmark. There, VERSALIFT took care of the assembly of the VDT-170 F elevating platform, including a workshop case and workshop equipment. This elevating platform reaches a working height of 17 metres and a lateral outreach of up to 10 metres.

Of course, such a road-rail vehicle requires a stability test. The Unimog underwent this test at ZAGRO in Grombach.

The ZAGRO team would like to thank all those responsible for the project for their excellent co-operation. Now it remains to wish the team at Holding Graz Linien a good and safe journey on the railway.