1300

theoretically.... but an inch doesn't leave much margin, and that's assuming they're properly maintained!

 

Dont forget under motion the water will be toing and throwing in the barrel

 

I realise that the "perfect" situation will be best achieved stationary on level track but wonder how much leeway one inch gives. Not a lot by the sound of it.

 

And when you've got a huge fire to get a class 2 to move an 8 coach train uphill.

 

Just to put the other side of the coin, in my road steam experience it is possible/unavoidable to run for relatively long periods with no water showing in the glass but a quick flick of the reverser will surge the water in the boiler and keep the crown cool enough to avoid the plug going! We always reckon the time to worry is when the glass turns misty and stays like it, as this means the bottom port of the gauge in the boiler is completely exposed to steam! [-o<

However, I don't suggest that this is a correct method of operation [-X and it's bloody difficult to surge the water with 300+ tons of train behind! #-o

 

class 2? I'm sure you mean class 3

[ Post made via Mobile Device ]

 

Doesn't really matter how far the plug protrudes above the water side of the inner firebox crown. The heat to melt the core in the plug is from the fire and conduction from the firebox crown into which it is fitted. It is because the crown is normally 'cooled' by the water above and being a tight screwed fit the fusible is also kept below the melting temperature of the core, normally lead (melting point of lead about 327°C, water at 150psig boils at about 185°C and at 200psig at about 200°C)

 

Thanks for the info, my inspector insists on there being approx an inch of thread in the waterspace. The heat to melt the plug is not directly from the fire but from the firebox crown, having the plug protruding through the crown by an inch will cause the plug(s) to melt before the crown is completely uncovered which is to me is a safer and better option.

Stan

 

Please see BR Handbook for Enginemen P 53:

"... the lead melts & allows steam to escape into the firebox, which acts as a warning to the enginemen. Should this occour, both injectors should immediately be put on, and steps taken to remove or deaden the fire"

Didn't something like this happen on the Weardale a couple of years ago?

 

Yes with Peckett 2150, 'Maerdy Monster', re: my earlier post on this subject

 

Good find that document Steve, an interesting and informative read.

 

Didn't Tornado have a problem with fusible plugs at the NYMR recently though not dangerous as this incident.

 

Think you'll find that the A1 had a leaking plug. A defect. That's an altogether different situation to dropping one.

Do you still have to inform the RAIB about dropped plugs?

 

I believe that the HMRI,or whatever it is called these days, are the people to deal with this type of situation unless someone is injured. Then the RAIB would be involved.
However, I stand to be corrected.

 

An interesting document thanks.

On a traction engine boiler, it is more than possible to get a 'drippy' plug with water in the glass, and thus over the crown.

It is possible to work a traction engine so hard that the blast draws flames through the tubes, smokebox and for them to come out of the chimney. Doing this can and does erode the lead in the traditional traction engine type plug, and the result is a leak. The NABIC plugs are better in this respect.

Also as you state, a steel firebox is much more forgiving, you railway engine boys would sh1t yourself if you'd have seen some of the hills I've been down. Even resorted to backing down a few, and a dodge is to throw a dampened hessian sack on the fire.

The inch gives you a margin. Though I have thankfully never dropped one, I have seen numptys who have, and sadly there are certain drivers who have a reputation for it. On a traction engine it certainly puts the fire out, and very quickly.

You see advertisments in old magazines. ''Plug droppers need not apply''

 

Strnage question cause i assume you need some type of road tax and insurance for a traction engine , but what sort of driving licence do you need for one .....do you need a driving licence for one ( in the sence of , you can get specialy quilifid for just traction engines ) ?

 

I believe that the HMRI,or whatever it is called these days, are the people to deal with this type of situation unless someone is injured. Then the RAIB would be involved.
However, I stand to be corrected.[/quote:8y4ahvbl]
It comes under RIDDOR. Dangerous Occurrences and is reportable to HMRI.
Pressure Systems:
2 The failure of any closed vessel (including a boiler or boiler tube) or of any associated pipework, in which the internal pressure was above or below atmospheric pressure, where the failure has the potential to cause the death of any person.

You could argue that the fusible plug is only doing its job and therefore hasn't failed but HMRI don't see it that way! In any case, you're caught out by:
Escape of substances
21. The accidental release or escape of any substance in a quantity sufficient to cause the death, major injury or any other damage to the health of any person.

The problem with the plug on Tornado was, I believe, a manufacturing defect, there being no undercut at the end of the screw thread and thus preventing it sealing on the face as it should.

 

If the reported damage to the loco is accurate, I suggest we await their findings with interest. And if you were anywhere near that engine on the day in question, I would think it might be best to say nothing until you have spoken to them.