MAIN TRUNK RAILWAY

Wanganui Chronicle, Volume 89, Issue 214, 10 September 1945, Page 4

MAIN TRUNK RAILWAY

SUGGESTED DEVIATION NEAR MiNGAWEKA ALTERNATIVE SCHEME Construction of a three-mile tunnel through the hills north of Mangaweka is envisaged by a retired civil engineer and suggested by him as an alternative to the contemplated deviation of the Main Trunk Railway through the Kawhat.au district. He :s familiar with the country and has made a study of the enginering problems involved. It is claimed that though such a tunnel would be a costly project it would save much climbing between Mangaweka and Utiku and result in quicker transport with lower operating costs. The pos- ' sibilities of the other deviation, across the River and through comparatively level country, are al present being investigated. “From Wanganui comes the news that, a deviation of the Main Trunk Railway between Mangaweka and Utiku is contemplated, in order to eliminate (he unnecessary climbing as well as troublesome tunnels on the existing line," the engineer states in a letter to the “Chronicle.” “With this object dn view trials are being made on the eastern side of the Rangittkei River, where it is considered a practically level line can be obtained, though two miles in additional length. This increase in mileage largely discounts the saving that w'ould be affected by the elimination of (he present stiff climbing. An alternative is therefore suggested. “The big bump in the gradients in this locality is the only place on all the stretch from Wellington to Taumarunui where there is quite unnecessary climbing. This being so, steps should be taken to cut. out the bump, with the result that there would be practically an even rise from Ohingaiti to Turangarere. Such a move would secure quicker, safer and cheaper running. “In my opinion this could be achieved by diverging from the existing line somewhere between Pouwhakarua tunnel and Mangaweka station yards, then folowing up the Mangaweka Flat to the site of the Mangaweka Viaduct, and there boring a three-mile tunnel, emerging two and a-half miles south of Utiku.

“A tunnel of this length would naturally be costly, but it would cut out seven short tunnels, aggregating one and a-quarter miles in length, besides the Mangaweka Viaduct, on the present fine. The maintenance and running costs would be so substantially reduced as to warrant a careful investigation of this suggestion.” A longitudinal section plan accompanying the letter indicates how' the suggested deviation would start from Mangaweka on a grade of 1 in 250. The tunnel would begin about two and a-ha]f miles further on and cut right, through the present Mangaweka “bank” on a grade of 1 in 1320, emerging at a point two and a-half miles south of Utiku.

It is understood as yet no detailed survey has been made of the other scheme through the Kawhatau district. Associated with this proposal is another that would have the effect of diverting thp main highway between Bulls and Taihape along a similar route, the object being elimination of the present winding road between Mangaweka and Utiku. A third suggestion linked with this dual-purpose deviation is that the Rangiitikei River be dammed at a point, below Utiku for hydro-electric works.

From a railway operating point of view a deviation would be a distinct advantage. The present, distance by rail between Mangaweka and Utiku is only e : ght miles, but. the winding track over this section includes no fewer than six tunnels. One of these, appropriately called the “Black Tunnel,” contains a wide curve and is always damp. This tunnel has given trouble on occasions and it is understood that its elimination is desirable.

From Mar.gaweka, 1072 feet above sea level, the existing railroad climbs to a height of 1324 feet, before dripping down to 1162 feet two miles south of Utiku. It then begins a lone: gradual climb to Taihane. The tunnel suggested by the retired engineer would also eliminate all this climbinc and there would be a considerable reduction in the running times of trains. It appears likely that ultimately some change will be made in the route taken by the Main Trunk line in this area.