Skip to content


Optimal mounting.

Bidirectional Unimog U500 with eight-spindle screw machine (ASM) 30.75.
Bidirectional Unimog U400 with eight-spindle screw machine (ASM) 30.75.

Both of these precision screw machines at PORR allow perfect results when loosening and tightening the rail mounting. The 8-spindle precision screw unit with a bidirectional unimog as a carrier vehicle enables fully automatic, synchronous loosening and tightening of rail fastenings.

Both the quality (through computer-supported recording of the torques achieved) and the performance is above-average compared with conventional screws.

Technical data.

  Typ Unimog U400 Typ Unimog U500
Manufacturer (Carrier vehicle) Mercedes U400, two-way system Mercedes U500, two-way system
8-spindle precision screwdriver unit  Robel Bahnbaumaschinen GmbH Robel Bahnbaumaschinen GmbH
Additional equipment, Loading crane HIAB-Kran XS 144E-3 Palfinger PK 9501
Motor capacity 175 kW / Mercedes Benz 170 kW / Daimler Benz
Total mass, max. 18 t 21 t
Driving speed (road), max. 90 km/h 80 km/h
Driving speed (track), max. 20 km/h 50 km/h
Length over buffers 8.100 mm 6.800 mm
Number of axles 3 2

Performance parameters.

                                         Typ Unimog U400.           Typ Unimog U500           
Performance, Screwing up to 600 m/h up to 600 m/h
Min. working radius ≥ 60 m ≥ 40 m
Min. driving radius ≥ 60 m ≥ 40 m
Towing capacity, max. 400 t -
Train control system No No
Safety gear change     Yes No

Learn more about railway construction.

Perfectly positioned.
Learn more
Modern treatment.
Learn more
Laying tracks
The best-laid tracks.
Learn more
Conveying – storing – unloading
Completely mechanised.
Learn more
Track surveying
Measurement and quality control.
Learn more
Vegetation control
Flexible control.
Learn more
Track-bound railway vehicles
For people and materials.
Learn more