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A Notable Transport Achievement
Page 80
Page 81
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An M.R.S. Outfit With 30 Wheels and Six Pivoting Points Successfully Carries a 981-ton Girder
AHERCULEAN transport feat wa.. carried out recently by M.R.S., Ltd., the well-known heavy-haulage concern. We referred briefly to this matter in our issue for last week, but we were not then in a position to give the full details.
The task conMsted of conveying a girder, 68 ft. long, 10 ft. wide and weighing 98i tons, from the London and North Eastern goods yard at Marylebone, to the new Cumberland Palace Hotel at Marble Arch, London, The outfit employed for the work consisted of the 100-ton Scammell 14-wheeled tractor-trailer and an Eagle 16-wheeled trailer.
Before attempting the task, the whole route had been planned' by the transport company's surveyor, and every turning and difficult point marked out, on a scale of 1 in. to the foot, on a flat surface. A model was then built up in Meccano to the same scale, which made it over 8 ft. long. This gave an idea of the exact clearances which could be permitted and the course to be followed.
The girder was carried by two turntables, one on the Scammell and the other on the trailer, and a new steering principle was discovered which greatly assisted in mancenvring. This principle was to couple side extensions from the load-carrying turntable on the trailer, to the front steering turntable of the trailer, adjustable links being employed. Theidea was to make the movement of the girder itself control the steering of
the trailer. There were actually six pivoting points on the outfit, these being the front wheels, semi-trailer fulcrum and hand-operated rear steering of the Scammell, the Eagle trailer front wheels and the turntables upon which rested the girder. In addition, the Scammell is so arranged that the front of the semitrailer can be 'lifted or lowered by hydraulic jacks.
It had been the intention to leave the goods yard at 7 a.m. the girder having been loaded during the night, but owing to a number of small difficulties the actual start was made about 11 a.m., the standard four-cylindered Scammell engine of the tractor-trailer experiencing not the slightest difficulty in hauling its
c30 colossal total load of something over 150 tons.
Mr. Marston directed operations from his vantage point on the girder. Enormous crowds impeded every movement and made matters difficult for the driver by hiding the kerbs, but steady progress was made at a speed of about 1i m.p.h., and a completely successful turn made from Limon Grove into the Marylebone Road. However, on straightening up
the outfit, it was discovered that the girder had slipped to the near side of the rear trailer to the extent of 13 ins., but it was found possible to bring this to its correct position by taking part of the weight off one ram at the front of the Seammell and putting more weight on the other, the girder then taking up its former position.
Early in the morning chalk marks had been made on the road to indicate to the driver the exact path he should follow, but, unfortunately, owing to the 'late start, these had been obliterated. It was possibly for this reason that a projection from the.turntable at the rear was in danger of fouling an electric main fuse box at the turning from Marylebone Road into -Edgware Road. It was a matter of only a few inches, but this one obstruction necessitated six reversals of the whole machine, the hand steering at the rear of the Scarnmell being utilized on each occasion.
'By the time this obstacle was passed the outfit had assumed a long Z shape, and when the turn was nearly completed there was a danger of the girder sweeping away a lamp post and an island post In the centre of the Edgware Road. To overcome this trouble, a powerful steam tractor was connected by a cable to the front of the Eagle trailer and this was pulled sideways while,,the Scammell pulled forwards. After several attempts, this further obstacle was passed, but another awkward complication then ensued. The end of the girder, this time, slipped to the off side of the trailer, partly owing to the camber of the road, but the tractor brought the end back into a more central position and the girder proceeded towards Marble Arch.
The trailer never quite regained its correct position in relation to the girder and Scamrnell, and was running somewhat crabwise and out of track to the off side, although the front steering prevented it from running outwards. As a matter of fact the actual slip;,of the girder was more apparent than real, being caused by the trailer running slightly out of line. However, very fair progress was maintained and the wide sweep from the off side of Edgware Road to the off side of Oxford Street in front of the Marble Arch allowed a perfect turn into Cumberland Place—the destination of the load.
The difficult turn into Edgware Road and the trouble experienced after it • occupied nearly three hours, but the corn wing at the Marble Arch took only a few minutes and showed that the unique method of pivoting and steering, although specially devised for this particular job, possesses great potentialities.
Everywhere along the route manhole covers, gullies, etc., which were crossed by the wheels were first covered by stout steel plates, but, of course, the distribution of the load over 30 wheels meant that each wheel carried a comparatively sniall weight—not much exceeding that of a bus.