THE TUNNEL

Evening Post, Volume CVIII, Issue 152, 24 December 1929, Page 10

THE TUNNEL

IMPORTANT DECISION

TO BE DEEPENED 2FT

FOE DOUBLE-DECKEBS

An important decision w ;( .s reached at yesterday afternoon's special meeting of tho City Council, that the Mount Victoria tunnel should bo mado two feet greater between floor and upper air duct to give space for tho running of double-decker tramcars or for specially high vehicles or loads. The additional cost is estimated at £5400.

In place of lifting the tunnel arch, the procedure to be followed is to drop the floor a couple of feet, and a satisfactory arrangement has been coino to between tho contractors, Messrs. Hansford and Mills, whereby this additional excavation will bo carried out. The concrete arching will not be affected in design other than tho dropping of two feet on either side in accordance with the lowering of the floor—the arch foundations go clown some- feet below the finished floor level.

NO TEAMS AT PRESENT.

For the present there is no intention of laying tram lines through the tunnel, for though it was quite well understood in 1920, when the tunnel loan was authorised, that it was to be a combined tramway and traffic tunnel, the tramway side of the work lias been dropped for the time being, for the sufficient reason that, the finances —1920 loan authorisation, plus unemployment relief loan, plus again Tramway Department contributions—are inadequate to cover the whole jol> of a tramway and general traffic tunnel. Moreover, double-decker tramears have not been particularly thought of for the run through Mount Victoria, but it was considered by the council that it would be very short-sighted not to make provision for that probable development in the future.

Already Wellington has had one sad experience of failing to look ahead in tunnel matters, for when the present tramway tunnel was being commenced in 1904 at an estimated cost of about £16,000, the contractors actually held up the work for some little time pend-. ing a decision of the council as to whether it should be made a two-track tunnel, at an estimated additional cost of a merc_£4774. The council turned down the idea, and later councils have never ceased to regret it.

A PARALLEL CASE.

The case of the Kiugsway subway, London, has a .particular bearing upon the decision reached by the council yesterday. This subway gives tramway connection between the northern and southern London tramway systems, and as such is of prime importance to the transport system of the whole city. It was constructed for ordinary tram traffic in 1908 at a cost of about £■145,000, and it is now being deepened to take double-deckers at a cost estimate^ at £250,000, i.e., almost double the original cost, due in large measure to the .tremendous expense involved in altering under-surfaco-services. The work, moreover, will take a year and must result in great inconvenience to traffic. This tunnel is 1100 feet long, 19 feet wide, and the floor is to be lowered from three to five feet, giving a clearance of 16ft Gin. The Mount Victoria tunnel will be 2045 feet long and 29 feet wide and will have a clearance when the lowering is made of ISf t 6in. Thus this tunnel is just about twice as long as the Kingsway subway, and much wider, and the lowering, though not so great, will involve the removal of a, good deal more spoil, so that £5400, up against £250,100, is not so bad after all.

Possibly had it been realised when the tunnel discussion was at its height, over likely tender prices, that so satisfactory a price as that given in by Messrs. Hansford and Mills would be quoted the plans would have provided for a clearance of 18ft Cm instead of 16ft 6in, but at that time the aim was to keep the cost down to enable the work to be squeezed through on limited finance. The additional cost, it is understood, will be met by the Tramways Department.