The gas pipeline diversion is needed to clear the way for the HS2 railway. The underground pipeline will run from south of the existing Chiltern Mainline to join the existing pipeline to the south-east of the Dogs Trust on Harvil Road.
The site team has already constructed two shafts using the diaphragm wall technique.
A 300m long, 1.8m diameter tunnel will now be constructed between the shafts using an Iseki tunnel boring machine, caled Elizabeth.
The project has recorded over 235,000 working hours with no lost time injuries.
Paul Gallagher, director from tunnelling subcontractor Joseph Gallagher, who is working on the tunnelling aspect of the project, said: “I speak on behalf of the entire Joseph Gallagher group when I say it is with great pride that months of collaborative endeavours, between all parties, has come together to facilitate the launch of ‘Elizabeth’.”
Work is ongoing and is due to be completed October 2019.