REPAIRand cleaning of tunnel linings has been simplified by the development of a range of rail-mounted tunnel scraping machines by Italian mining equipment supplier Costruzione Macchine Marconi.

The FGF 75 and FGF 110 rail tunnel scraping machines are carried on a bogie well frame, with a power pack above one bogie and a small hopper above the other. The cutter heads are mounted on flexible booms which can be rotated or extended to follow the curvature of the tunnel lining. The arm is able to reach both sides of a double track tunnel during a single pass.

As well as scraping away limestone build-up or damaged brick from the tunnel linings and cross walls, the FGF machines can be used to cut transverse grooves for drainage pipes or reinforcing ribs. When substantial quanties of material are being removed, a series of conveyor belts can be fitted to transfer the spoil to a separate wagon.

The FGF 75 has a 75 kW power pack and 50 kW cutter heads, whilst the bigger FGF 110 has a 100 kW power pack and 75 kW heads. The FGF 75 is able to cut to a depth of 80 mm, and the FGF 110 can reach 180 mm.

The cutters rotate at between 63 and 100 rev/min, allowing the units to treat up to 30 and 60 m2/h when working in brick. These figures fall to 25 and 50 when the linings are concrete. However, Marconi warns that the output rates depend on the type of material being excavated.

Costruzione Macchine Marconi, Italy

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