Pink engine?!

Besides the famous Duck, and Bittern, several other A4s had bird names:

4482 Golden Eagle
4483 Kingfisher
4484 Falcon
4485 Kestrel (renamed Miles Beevor)
4486 Merlin
4487 Sea Eagle (renamed Walter K. Whigham)
4488 Osprey (renamed Union of South Africa)
4489 Woodcock (renamed Dominion of Canada)
4493 Woodcock (name reallocated from 4489)
4494 Osprey (reallocated from 4488 but renamed Andrew K. McCosh)
4495 Great Snipe (renamed Golden Fleece)
4497 Golden Plover
4462 Great Snipe (reallocated from 4495 but renamed William Whitelaw)
4463 Sparrow Hawk
4464 Bittern
4465 Guillemot
4466 Herring Gull (renamed Sir Ralph Wedgwood)
4467 Wild Swan
4468 Mallard
4469 Gadwall (renamed Sir Ralph Wedgwood, destroyed in air raid at York and name transferred to 4466)
4499 Pochard (renamed Sir Murrough Wilson)
4500 Garganey (renamed Sir Ronald Matthews)
4900 Gannet
4901 Capercaillie (renamed Sir Charles Newton)
4902 Seagull
4903 Peregrine (renamed Lord Faringdon)

 

GNR(I) V class: https://en.wikipedia.org/wiki/GNRI_Class_V

No85 Merlin is the sole survivor and is actively used on the mainline:

Photo from www.steamtrainsireland.com

Keith

 

Stormin' engine, that 85.
Pat

 

Had a smashing run behind 85 last summer... until (apparently) water level trouble occurred and the fusible plug went. Fire thrown out and towed back by a diesel. But pelting over the Wicklow mountains behind was absolutely amazing and will stay with me a good while.

 

It looks quite like a school with no side plates. It looks like a nice engine and bet it was a good run it is a shame it didn’t go all the way. I have googled fusible plug for you and it means a high temperature is reached and it’s like a warning light of an explosion for the driver. So it’s actually very dangerous if you were on the train. I have been googling a lot and if it was a good run I bet they had a blower on to make it get more steam and it could have been too much and is why the water level trouble happened.

 

Please stop saying things like this. There was absolutely no danger to anyone on the train.

Keith

 

Have you ever driven, and not just a driver experience day, or even fired a steam engine? I suspect not; had you known what you were talking about you wouldn't have said all that.

I don't know the circumstances of the incident, but putting the blower on wouldn't do what you suggested. It's more likely there was an injector problem, but I don't know. but the crew did the right thing: stop, put the feed on if you can and throw the fire out whether or not. There was no danger to anyone in those circumstances described.

 

Having been on trains in these sort of circumstances, I can entirely support that there is no need to be apprehensive of dropping the plug.

A fusible lead plug is simple, reliable and safe - certainly so compared to what ensues with an overheated crown sheet, which was not unknown in WWII on American locos over here, ie "relative risk" - wether water or steam coming down the the first effect is to lower the temperature of the fire as the same time as losing the pressure in the boiler.

 

A fusible plug is certainly a safety device, but I am not sure that, if one fails, the leak of water / steam would have much noticeable cooling effect on the fire, nor reduce pressure. Indeed, there are several stories of crown sheet collapses on large locomotives where the fusible plugs must have failed many minutes before failure without the crew noticing.

If you consider the regulator ports on a large locomotive, they are several tens of square inches when fully open. A fusible plug is perhaps 1/2" or less in diameter: if it fails, that is a hole venting steam into the firebox a few tenths of a square inch in size. So the rate that steam can escape through a dropped plug will be minuscule relative to the rate that the fire is capable of generating steam to keep up with a wide-open radiator. Fortunately I have never experienced it for real, but for a loco that is working hard, the most noticeable thing I suspect would be an unusual sound and maybe a strange deflection in the white heat of the firebox; the damping effect would I think be negligble. Certainly the oft-stated point that a dropped plug "causes the fire to go out" is nonsense.

I was once on a loco (visiting ...) that suffered I believe a tube failure. The result was a considerable amount of water running down the tube plate, I suspect more than would leak from a dropped plug, but the impact on the fire was fairly negligible - and that was with a loco at rest and the fire with minimal draft on it. We hooked off the train we were due to haul and threw the fire out, even though we never had any difficulty maintaining an adequate water level.

Tom

 

I hope you're taking notes from this Tom!

 

A damper on a steam loco is not a way of dampening the fire.

Just like a damper on a domestic coal stove (sadly now uncommon) it is a means of regulating the air flow through the grate.

By regulating the airflow it is possible to control the way in which the fuel burns. One of the things which a fireman learns is how to balance the 'bottom air' through the damper(s) and the 'top air' through the firedoor(s) in order to achieve the most complete combustion, limit the amount of smoke, and control the temperature of the fire to match the changing demand for steam.

 

Every day a school day!
Pat

 

its just the same as when you are short of steam using the injector to give the fire man a shot of adrenaline so he shovels faster.

Colin

 

Any idea that a failed fusible plug will dampen the fire or reduce the pressure is the stuff of fantasy. Tom has given good reason why. All the engine mans manuals say that if a plug goes you should take immediate steps to dampen or throw out the fire. It takes a brave or foolish crew to do this if the crown is truly exposed as every second of overheating means the firebox is nearer to collapsing with its inevitable consequences.

 

The fusible plug would have dowsed the fire in the very early days on engines with very small fireboxes; it seems to happened with Sans Pareil at the Rainhill Trials in 1829. Fireboxes outgrew this situation, probably quite soon. The plugs became a warning devise only, telling the crew of the situation and that urgent remedial action was needed. The dampers would be involved: you'd close them to prevent air passing through the fire to liven it up.

 

Some of us here are very knowledgeable about the design and/or operation of steam locomotives. Some of us about other subjects. Some of us have a lot to learn. All that is fine, but "a little knowledge is a dangerous thing". I am feeling the need to Ignore one contributor again, even though it can be confusing to see responses to a posting that one can't see.

 

You say the fusible plug but I know on a Merchant Navy there are six of them so is that because the crew may not notice the effect of one plug failing in a 48sq ft firebox? I assume other large firebox engines are also fitted with multiple plugs.

 

I's assume - I don't know - that the objective of more fusible plugs was to make more noise so more likely to attract a crew's attention. The crowns of big, especially Belpaire, fireboxes tend to slope downwards towards the rear, so it's generally the front ones which will give way first.

It's also not unknown for a plug not to give way. This happened to some 8Fs in the Middle East. Mind you, investigation revealed that, instead of lead, they had been filled with cement . . .