LYTTELTON TUNNEL.

Otago Daily Times, Issue 19906, 28 September 1926, Page 10

LYTTELTON TUNNEL.

WORK OF ELEOTEIFICA TION. A £200,000 JOB. (FeOM Odß OWS CORftESPONDENT.) WELLINGTON, September 27. The electrical branch of the Public Works Department has received instructions to put in hand the preliminary work in connection with the electrification of the Lyttelton tunnel, 'ihe cost of the work will ruti into about £200,000} and it will take adout two years to complete. Ihe specifications for material are not vet hnally settled, and until this is done tenders for material cannot be invited. The department states that it will be at least xViaroh next before the poles will be erected for the overhead equipment. Some time ago a committee of experts, consisting of Messrs F. T. M. Kissel {chief electrical engineer, Public Works Department), J. E. L. Dull (designing engineer, Public Works Department), A. S. Wansorough (designing engineer), and G. W. Wyles (assistant signal and electrical engineer, both of the Kailway Department) was set up tor the purpose of reporting on a scheme for the electrification of the tunnel, covering also a general scheme in respect to electrification and the method by which the work should be carried out. This committee considered the extending of electrification to Middleton, but, in view of a proposed method of working traffic outlined by the Railway Department, came to the conclusion that no additional advantage would be gained by so doing. The committee recommended that the limit of the electrification area be confined to certain sidings in Lyttelton, Christchurch, and intermediate stations, the main line between Lyttelton and Christchurch, and certain roads in the Christchurch yard. The following scheme was ieve...mended by the committee, and it has been adopted: The tractive voltage to be 1500 D.C., and to be supplied from a sub-station situated in the vicinity of Woolston. The power to be supplied to the Substation at 11,000 volte A.C. from the Public Works sub-station at Addington. The railway sub-station to be « m ■■ cally controlled and to be equipped with two units of about lucici m. .. .. switching arranged so that the second unit will come into operation automatically under peak conditions. The overhead to be of the single catentry type, with copper catenary throughout, in order to reduce feeder cables to a minimum. A very full investigation was made in regard to the method to be adopted in the tunnel. The problem was complicated, 'as a considerable portion of the tunnel is unlined, and has a very irregular section. The smoke conditions are bad. and with a normal time-table only five or six hours in the 24 are clear of irainc. The installation of a third rail was considered in preference to overhead, but this would complicate the locomotive design unless the whole scheme were made third rail, and that was not recommended. In view of the simplification of modern overhead construction, the conclusion was reached that the overhead should be continued through the tunnel. The approximate estimate of work is as follows; — Electric locomotives £01,200 Sub-station at Woolston ..... •• 30,000 Overhead equipment, 22 miles of single track 60,000 Alterations to engine shed at Lyttelton, telegraph and telephone requirements, etc. 10,000 Contingencies, etc., at 20 per cent. 32,240 Total .. £193,440 In accordance with the recommendations of the committee, the work will be carried out as follows:—The sub station arrangements for the supply of power will be carried out by the Public Works Department, which will supply the railway with power at 1500 volts from the sub-station. The complete cost of the sub-station will be a charge against the Railways Department, but the operation will be carried out by the Public Works Department. The design generally of the whole work will be earned out jointly by the Public Works and Railways Departments. The committee considered the question in regard to the letting of contracts, and was of the opinion that contracts should be let for the supply of fabricated material and plant. The tenders for the supply of material will be dealt with by the special committee mentioned above. Mr G. S. Lynde, chief mechanical engineer. Railways Department, will be associated with the committee to give advice in connection with the purchase of locomotives.