Orders in for Herrenknecht Tunnel Enlargement Systems

The two machines will refurbish the 160-year-old Fachinger and Cramberger tunnels. The 426m-long Fachinger Tunnel lies between Diez and Fachingen; the Cramberger Tunnel between Balduinstein and Laurenburg is 732m long.

Typically refurbishment restricts use of the tunnel, requiring rail operators to re-route trains or provide bus replacement services, or construction work is limited to night hours, all adding to the project’s time and cost.

The TES, however, incorporates all equipment required for the refurbishment or enlargement, including a protective canopy that separates the working area from rail traffic. This allows services to continue while work is carried out.

Herrenknecht project manager Volker Breuning said enlarging and relining a tunnel with the TES resulted in a cross-section and durability similar to a new tunnel.

The TES is around 40m long and the machinery required for the project, such as excavator boom with hydraulic breaker, remote controlled shotcrete nozzle and drill rigs.

“The TES uses drill and blast to enlarge the tunnel; the material falls to the side of the machine and is taken out by separate tunnel heading and loading machines,” said Breuning.

Herrenknecht supplied its first TES to a rail tunnel upgrade in Spain in 2017 and expects good demand for the technology. A recent webinar attracted a global audience.

Tunnels around the world are ageing and require refurbishing and upgrading, perhaps to meet current regulations, modernise emergency provisions, or renew the lining. In the case of rail, tunnels may need to be enlarged to accommodate wider gauges and faster trains or to electrify the line.

In Austria, Switzerland and Germany alone there are 201 tunnels built between 1850-1870, 395 tunnels built between 1871-1890 and 186 built in the following two decades.

“Tunnel refurbishment is mainly driven by rail operators but it could also work on road tunnels,” said Breuning.

At present there are two stages to the work – excavation and primary lining, followed by the permanent lining – and Breuning said it would be a good option if the two stages could be combined. “But this is an outlook for the future and to be developed,” he said.