BD Nuclear Steel Wire Sawing Success in Paris Metro Tunnel

29th June 2022

BD Nuclear were contacted by Herrenknecht, who manufacture and decommission tunnel boring machines around the world, regarding the boring unit they had supplied for the new metro line in central Paris.

In the process of decommissioning, they discovered that part of this particular machine could not be removed complete and needed to be reduced in size within the 3.5km metro tunnel.

Following a site visit in Paris and with his expertise in steel wire sawing, Managing Director, Dave Dougan was confident they could complete this unique task which had never before been attempted.


BD Nuclear were required to size reduce a main drive unit made from hardened steel, weighing in excess of 80 tonnes. To do this efficiently, six cuts were planned to divide the unit into sections. Each piece weighing approximately 13.5 tonnes and measuring 1.8m x 1.2m.

Four operatives, working 24 hours a day in split shifts, over 7 full days enabled the job to be carried out seamlessly.


Dave Dougan explained “We opted to use 2 Hilti WS 30’s with standard pulleys, Hilti steel wire and different set-up configurations as required.”

He continued “The wire saws ran for 20 hours a day, as each cut took this long to complete, with both saws and wire working perfectly. On completion of every cut, lifting points were welded onto each section for support and to enable gradual lowering and handling. The client then very skilfully removed each section from the tunnel.”

The job was a great success, completed three days ahead of schedule, resulting in a very happy client.

Great job BD Nuclear!