Bluebell Motive Power

Similar happened at Wheatsheaf Junction (the GWR case) - the crew heard escaping steam but, because they believed teh water level to be normal, did not suspect a fusible plug and instead thought it was a tube failure; they elected to go on and fail the locomotive at the next station where a replacement could be obtained:

4. The explanation for this shortage was found in the water gauge, of which there is only one, in accordance with the former G.W.R. practice. There was a clean break across the glass tube about an inch from the top. This had occurred inside the rubber packing washer, with the result that there was no leak or external indication of the fracture. The top portion of the broken glass had moved up slightly in the available space, allowing the rubber washer to squeeze into the fracture and spread itself across the bore of the glass tuhe until an aperture of barely 1/16 inch diameter remained, when it was examined after the accident. This reduction of the bore near the upper end would have the effect of reducing the pressure of steam on the top of the water in the glass allowing it to rise above the level of that in the boiler, thus giving a false reading.

The difference between the two levels could not be determined with certainty as it depended upon the extent of the restriction under boiler pressure. It must have been considerable, however, as when Brazier and Cook heard the first sound of escaping steam in the firebox, which was undoubtedly due to the fusing of the front plug on approaching United Collieries box, half a mile short of Wheatsheaf Junction, they noticed that the water was almost at the top of the gauge glass and this was immediately confirmed by opening and closing the drain cock. Consequently they did not suspect or even attempt to look at the fusible plugs, hut concluded that a tube had failed and, when passing United Colliery Signal Box, Brazier called to the signalman that another engine would be required at Wrexham.
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Source: https://www.railwaysarchive.co.uk/documents/MoT_Wheatsheaf1952.pdf

Tom

 

This is interesting and informative stuff - thank you for posting it.

Looking at the drawings at the beginning of the report I was surprised that the test cocks and the water gauge share the same feeds from the boiler meaning that a blockage at that point would affect the workings of both the test cocks and the gauge simultaneously, which is some that is avoided if you have two completely separate assemblies.

Steve B

 

I mentioned that in one of my earlier posts. The passageway is a single line component which should always be avoided with anything critical. Another inherent problem is that, as long as the gauge glass appears to be reading, the crew will not routinely check it with the try cocks. You will only use them for an initial test to see that they are working but never as a routine quite simply because they are a pain. The last thing you really want is high pressure steam and water being blown out of a fitting, however small the opening is.

 

I've been reading the recent posts with interest. I understand the concept of try cocks, but have never been on a footplate when one is used.

Is it as simple as open it up, if you get scolded by high pressure steam, the water is below that point... If you get scolded by hot water, water is above that level?

 

Kind of (though you try not to get scolded!)

The complication though is that the water in the boiler under pressure is at a temperature considerably above 100C. So if you open a cock and water emerges, it instantly flashes to steam anyway as the pressure is released - so in practice, you get either steam, or a kind of mix of wet steam and droplets, not especially easy to distinguish. At night I suspect the problems were even worse.

Also, as noted by @ruddingtonrsh56 you don’t get a reading of level, but instead just limits within which the level is.

They aren’t something I’d be keen on using on the move as the only source of water level.

Tom

 

Many years ago a friend on Mine was driving a traction engine with one glass, and one tri-cock (the only true reason for not using two glasses is saving money, whether justifiable or not). The glass broke and He had to bring the engine home on the single tri cock, His method was to push a piece of rag into the spout of the valve, which He then 'cracked' open, He then ran home working on the principle of 'Rag dripping, injector off, rag dry injector on'

 

Rodding through of waterways (or rather not rodding them) brings the Thetis disaster to mind. (this is not being critical of your comment)

 

Thanks for explaining. That sounds... Less than optimal... As your back up safety feature!

 

If you must have tri cocks on an engine, this is the sort that I would like to see - easy to operate and relatively safe


Picture taken on Harz Mallet 99.5902 before working a special up the Brocken. Clearly the use of a single gauge glass and tri cocks was not confined to the GW but for an engineman two glasses has to be preferable.

Peter

 

That is just not quite correct. I agree about the steam water mix when you open the valve full, but if you set a try cock so that it is just dripping and leave it at that all the time it is very easy to distinguish when the water has gone and it is just steam blowing...

 

Goulash Soup. Yes, please!
Also interesting to see the boiler test dates in situ. Stops all our arguments about '10 year tickets'.
Pat

 

As Tom says, trying to distinguish between the two is not aa easy as either water or steam. The trick I find is to just crack the valve so that you get either a wisp of steam or drips of water. If you open them too much it's very difficult to tell what you've got. Another thing to do is always open the bottom one first. If you open the top one first you end up with a jet of steam spraying onto the bottom cock right where you want to put your hand.

(Thought I'd posted this earlier before I went out.)

 

I will raise you a power reverse and two water gauges.

 

https://www.bluebell-railway.com/bluebell-times/

The Q has now had its boiler lifted and there is an update on 84030

 

From the latest Chairman’s update:

“Secondly, we have agreed with the Atlantic Group that when Beachy Head moves into the main works early next year they will take on the projects of Normandy and the Adams radial tank; this is very exciting (especially Normandy is such a versatile and powerful loco, ideal for shunting... and I am a shunter!).”
​

My understanding is that funding for Normandy will primarily be from the Bulleid Society (the owners) and the Radial Tank from Bluebell sources.

Tom

 

Great to hear about the Adam's Radial. Although I must say the operational Bluebell fleet over the next 5 years or so looks like it could quite large. 32424, 34059, 263, 928, 541, 96, 30583 and 92240 all are undergoing or about to have work undertaken on them and then 73082, 80151 and 72 all currently in service and, all being well, will hopefully be in steaming that timeframe.

 

Makes a change from having to hire in some copper-capped junk* to make up the numbers! Tho I suspect the Adams and the 9F at least will take a good 4-5 years.


*Yes, I am baiting!

 

Wow, fantastic news! Presume this means the Dukedog is further down the list now then?

Chris

 

30583? I'll forgive you - just once

Being serious, I suspect 488 and 92240 might take longer than 5 years. In 5 years time I think 80151 will either be out of traffic, or imminently out of traffic. There is also 27 under overhaul.

So potentially you have 928, 541, 263, 96?, 27? (early in ticket); 34059, 32424, 72 (mid ticket); 73082, 80151? (near end of ticket). It would be a much healthier fleet than now, but still short of medium (class 1 - 2) engines - hopefully 592, B473 or (most likely) 9017 would follow 263 into the works. My personal concern would be 92240, in that there is simply a lot of it, and big locos seem to take a long period to go through the works during which time they make it harder to progress other locos.

Tom

 

80151s ten years would be up in Spring 2029 so it's already near abouts the halfway point. 73082 would still have about two years left then. Obviously as long nothing major goes wrong with them