SUBSIDENCE OF A RAILWAY.

Clutha Leader, Volume IV, Issue 197, 19 April 1878, Page 7

SUBSIDENCE OF A RAILWAY.

— qp It will be remembered that,considerable difficulty was experienced by the contractor for the Olutha. line through the subsidence of th« swamp near Stirling, Similar difficulties annear to be met with elsewhere, as will be seen hy the following from the Waikato Times : — -The Ohaupo extension of the railway was not opened i'or traffic yesterday. The springy spot a few miles from Ohaupo gave way on Friday, and lefb a large gaping hole in the centre of the line. Un Saturday fully a hundred tons of ballast were filled in, but the pit absorbs it almost as fast as it is laid down. By yesterday morning the contractor did succeed in getting it filled in a foot or two above the lev«l of the railway, and a rake of ballast waggons brought, something like a hundred tons of gravel, and deposited them on either side the line to fill in the hole as the gravel in it subsided. But during the course of yesterday not only had the main hole sucked down all that was put into it, but a hole, as large as would swallow a man was seen to form in the heap of ballast on one side the liae and the. gravel commenced to settle down into the vortex like sanri in an hour glass. We understand that it has been proposed to divert the line at this point, and it is undoubtedly the best course the Government can sanction. To in- j sist on filling up the vacuum would lead to enormous expense, and never make a safe work of it. At this spot the swamp has been bored, and a depth of between thirty and forty feet reached without finding bottom. ]Mor does it : mean : simply filling up a hole, of certain dimensions, for -as -the- gravel is absorbed, its weight forces it oiilwards in all .directions; under the crust of the swamp, and it is impossible to say but that a mountain of ballast would be fe^ quired to .fill up a hole; tinder such £qh- , ( ditibn's; ..-*" ;•'