Daunting Year Ahead For Bay Bridge Retrofit

THE NSW Government is undertaking electronic monitoring of the $2.3 billion Epping to Chatswood rail line after cracks appeared in the tunnel and its builders conceded the infrastructure would not survive a mandated 100-year life span.

A 24-metre section of the tunnel is under surveillance for any movement while trains continue to use the line and plans are being drawn up to repair the tunnel. The cracks were discovered six to eight weeks ago.

The area is where pits were dug to drop in the tunnel-boring machines that carved the length of the 13-kilometre underground railway, near the corner of the M2 and Delhi Road.

Advertisement: Story continues below The cracks appeared in the arches that were built to support the roof of this section, which was replaced after the boring was completed.

The tunnel's builders, Thiess Hochtief, are worried that it will not last until 2109, a minimum life span dictated by the NSW Government contract.

The Government insists the tunnel is safe for passengers

Last year the Herald revealed serious defects had emerged in the project that threatened its long-term reliability, after being leaked a secret Government report which exposed thousands of flaws in the way the tracks were fixed to concrete slabs