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 Post subject: Travel gearing
PostPosted: 20 Jan 2012, 23:43 
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Joined: 07 Jan 2011, 17:55
Posts: 25
Bet you full size boys wish you could get at yours this easy!!!


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travel gearing3.jpg
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travel gearing4.jpg
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 Post subject: Re: Travel gearing
PostPosted: 17 Feb 2012, 11:02 
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Joined: 23 Dec 2010, 00:07
Posts: 384
Location: Poole, Dorset
John,

It has long been established that we can get at it, quite easily; it is just that putting it the right way up again afterwards isn't so easy!

(DS1196 was cut up after the incident below, but GWR 2 as we know survived both these mishaps).

Roger


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DS1196 Brighton Oct 1964.jpg
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GWR 2 Con Yard Swindon Sep 1962.jpg
GWR 2 Con Yard Swindon Sep 1962.jpg [ 13.73 KiB | Viewed 32937 times ]
GWR 2 St Budeaux April 1934.jpg
GWR 2 St Budeaux April 1934.jpg [ 32 KiB | Viewed 32937 times ]
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 Post subject: Re: Travel gearing
PostPosted: 15 Oct 2012, 00:16 
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Rather an extreme way to get to a couple of grease pots!! Seriously, how do you manage to turn one over? Is it because the load is lifted too high , then slewed or derricked out beyond the point of no return, it can't be a straight lift because you would feel it tipping and be able to stop the hoist. John


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 Post subject: Re: Travel gearing
PostPosted: 15 Oct 2012, 10:29 
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Joined: 23 Dec 2010, 00:07
Posts: 384
Location: Poole, Dorset
John,

The most common causes for a crane toppling under load historically are underestimating the load then slewing, or a failure of the ground or propping system. Occasionally there have been other factors such as an uncontrolled slew caused by external factors.

The three photos in my post all fit into these categories. The top photo (BR(S) DS1196 at Lovers Walk Sidings, Brighton) fell because the man in charge failed to appreciate that a motor bogie was far heavier than a normal (non-motor) bogie, and the crane fell as it was slewed to the side.

The second photo (GWR 2 in the "Con Yard" at Swindon in the 1960s) was the same cause - the crane was lifting a fragment of scrapped loco which was heavier than had been estimated, and fell when slewed. Fortunately the scrap line cushioned its fall and saved the crane from damage - there can be little doubt that it would have been scrapped had any significant damage been sustained at this late year.

The circumstances of the St Budeaux accident in the third photo (again GWR No 2) are more unusual. In this case the two cranes were travelling with the recently-removed bowstring girder suspended between them, taking it from the work site to a nearby siding where it was to be loaded onto "Pollen" wagons for removal. Reports state that a sudden gust of wind caught the girder and caused the crane to fall. Working free on rails with a load of that magnitude it would only take minimal slew or lateral load to topple the crane, so although the exact failure mechanism is not known it is entirely feasible.

There have been many examples over the years of failures of the support system causing falls. This may be the ground giving way due to thawing (as in the case of Hixon, 1968), packing being set up on ground that is softer than thought, and in the very early days there was at least one incident when the propping girders buckled and failed. I have no doubt that there have also been accidents caused by the permanent way failing (for example the gauge spreading) under the crane.

It is hard to imagine in this day and age, but it is important to remember that in the steam breakdown crane era there were no safe load indicators and no load-on-hook measuring systems, and only very rudimentary radius indicators. The safety of the whole operation depended upon someone having the experience to estimate the load correctly, with the sole backup of someone watching the back side wheels of the crane for signs of unloading.

A cardinal rule of lifting with a crane such as this is to keep the load as near the ground as possible, so that if the crane does start to go over the load will land and come off the crane before the crane has reached the point of no return.

Roger


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 Post subject: Re: Travel gearing
PostPosted: 15 Oct 2012, 17:12 
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Joined: 26 Dec 2010, 19:06
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An example I have seen, though not of a rail crane was at BREL York in about 1988.
The resident Rail crane was out for servicing and as was usual a road crane was hired in to cover the placing of scrap skips.
The crane was overturned when lifting an EMPTY Skip.
The operator neglected to put out his stabilisers.

It also still happens today as illustrated by the Kirow incident a few years ago when lifting a short concrete track panel.
download/file.php?id=193&mode=view

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Bryan

http://www.nymr-pway.co.uk/


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 Post subject: Re: Travel gearing
PostPosted: 16 Oct 2012, 09:06 
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Joined: 16 Feb 2012, 17:58
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Location: Near Redruth, Cornwall
Roger

I think you have covered most things regarding a crane toppling over, one point you has left out that has happened in the past and almost happened when I was in the Brighton Gang was the jib being raised too high.
I recall an incident with ADRC 96701 Ex Stratford 75 tonne in Hove yard.
When we were learning to operate the crane, we raised the jib for the first time and gang members on the ground pointed out that the jib radius indicator was being exceeded, the crane was stopped and the jib lowered. We realised that the radius indicator in the cab was faulty, it was lucky that the jib did not go backwards over the cab, or if we had been slewed around to one side the crane may have even toppled backwards.

Mick


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 Post subject: Re: Travel gearing
PostPosted: 16 Oct 2012, 10:36 
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Joined: 23 Dec 2010, 00:07
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Location: Poole, Dorset
Aha, yes of course, thank you Mick!

Most of the later cranes (i.e. from the 1939 45-tonners onwards into the diesel era) were tail-heavy and would fall over backwards if slewed through 90 degrees with the jib at too small a radius. In addition some cranes which were not tail heavy will become unstable if slewed (either at maximum or minimum radius) on canted track. The 75 tonners were notoriously tail heavy and most I think fell over backwards at some stage.

The other cause for a crane falling over backwards is if the load comes off unexpectedly, for example if the chains fail. The dynamics of the sudden unloading of the crane will cause it to rebound and this can in extreme cases cause the crane to fall backwards. I came across a video clip somewhere (I will try to remember where) which showed the whiplash effect rather well, though fortunately the crane didn't go over.


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 Post subject: Re: Travel gearing
PostPosted: 29 Jan 2013, 11:35 
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Joined: 28 Jan 2013, 21:13
Posts: 5
Hi John

Model looks exceptional, and is just the detail that can help others in the construction of models.

May I please ask on what crane has this been modelled? as I am gathering info. on the R&R 36ton ADRR95201 in preparation of making a start

Thanks for your trouble

Ian


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 Post subject: Re: Travel gearing
PostPosted: 03 Feb 2013, 21:12 
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Joined: 07 Jan 2011, 17:55
Posts: 25
Hi Ian, you have set yourself a very enjoyable project. "My" crane is the Craven 25T last seen parked outside the NRM. I managed to photograph and measure it before "elfandsafety" ruined all our fun!! A small hint; when you get access to your chosen love, take a piece of wood, marked off in inches, and place on strategic points and take 100's of photo's. you will be suprised how the insignificant ones will come in handy to see the half hidden bits.

Best of luck and keep us informed of your progress.
John


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