TRACTION ENGINES

Hawke's Bay Tribune, Volume XXV, Issue 78, 15 March 1935, Page 12

TRACTION ENGINES

Do Not Damage Bitumen HASTINGS ENGINEER REPORTS Investigations into the probable effects of traction engines on bitumen roads in the borough of Hastings were i recently made by the borough engineer, Mr C. E. Evans, whose conclusions are contained in the following report submitted to the council at its meeting last evening.— “The foundations for our bitumen roads are constructed with the use of a 13-ton roller with a weight of rWe tons rn a 17-inch rear wheel This gives a weight of (>sBlbs. *»er inch width, and traffic using the road should not exceed this weight. Jn fact for sealed roads, unless the foundations are specially constructed and of heavy type, heavy speed trucks which have a tendency of breaking the seal should be well below this weight per inch of width of tyre. “Under the regulations solid rubber tyres of seven inches in width are permitted to carry 700 lbs per inch in width. Pneumatic tyres are not dealt with under the regulations, but the makers give the carrying capacity of a seven inch pneumatic lyre at tiOOlbs. per incfi of width. A traction engine weighing 71 tons has a weight of 2j tons on the rear wheel IS inches wide, or 312 lbs. per inch of width. “From the above remarks it will be seen that the weight transmitted to Ihe road bv the various classes of traffic already dealt with are decidedly in favour of the fraction engine, and provided tho surface of flic wheels of I hose machines is smooth they should not cause, any damage to our ‘hot mix’ bitumen surfaces, or even the lighter class as the strength of foundations is increased by the thickness of ‘hot mix.’ “With regard to the sealed roads, nrovided the surface was free of loose stones. wbicj) might be forced into the inface, thereby breaking the seal and ,-lowing water to penetrate to the foundations. d could be expected that hentv lorries moving at high speed would cause more damage than the Ini. -need traction engine with small weight per inch of wheel.’’