New tunnel for main trunk line

Press, Volume CXVI, Issue 34085, 24 February 1976, Page 5

New tunnel for main trunk line

A railway tunnel on the North Island main! trunk line that was built in the 18510 s will be re-j placed. The work is part of the] : Railways Department’s gen-] feral improvement programme for its main rail 1 : fink. The existing tunnel, ! which is at Porootarao, about 50 ,km south of Te ■ Kuiti, is relatively 7 small in diameter, and subject to speed restrictions that make I it a bottleneck for trains travelling betw-een Auckland and Wellington. Investigations had shown that it w 7 as more practicable to build the new 1359 metre tunnel, than to repair the old one, said the chief civil

.engineer for the Ministry of! i Works and Development (Mr! ; A. G. Stirrat). i “Upgrading would mean ! closing the rail link for an ! indefinite period, while enlarging and relining was done.”, Two features in the construction of the new tunnel, which will take several years to complete, will be the use of a drilling machine, and the spraying of concrete on the newly excavated surfaces to hold them temporarily until the finished lining , is constructed. Work on the approaches to the southern portal would take as long as the construction of the tunnel itself because of sloping unstable land there, Mr Stirrat said.