Kirklees boiler incident

[martin_wynne]

From the RAIB today:

 

http://www.raib.gov....03_kirklees.cfm

[PaulRhB]

I can only assume it was a partial melting of the fusible plug, they are pretty hard to miss when it let's go into the firebox! At least no-one got hurt.

[PhilH]

I can only assume it was a partial melting of the fusible plug, they are pretty hard to miss when it let's go into the firebox! At least no-one got hurt.

 

Quite right about the no one got hurt bit, but you can't have a partial melting of the fusible plug. They either go or they don't.

The bit I don't understand is the crew missing the fact that it did let go.

[Boris]

Looking at the way this is written there may be more to the story than the initial statement suggests, I've been involved in the preservation movement for quite some time and over the years I have seen a number of interesting "variations" on fusible plugs. You can have a partial melt of a fusible plug, usually from a result of slight overheating rather than firebox crown exposure as detailed here, it is however quite unusual. There may be more to this story than the initial report suggests, we'll have to wait and see what the report says in 12-18 months time.

[PhilH]

You can have a partial melt of a fusible plug, usually from a result of slight overheating rather than firebox crown exposure as detailed here, it is however quite unusual.

 

But isn't that how you get overheating, ie crown exposure even if it's momentary. You wont get it if the crown is covered with water.

[Edwin_m]

Similar incidents have happened before where the water gauge was defective or its valves were not properly used, and the crew didn't realise the problem despite the fusible plug:

 

http://www.railwaysarchive.co.uk/documents/MoT_Honeybourne1943.pdf

http://www.railwaysarchive.co.uk/documents/MoT_Thurston1944.pdf

http://www.railwaysarchive.co.uk/documents/MoT_Lamington1948.pdf

http://www.railwaysarchive.co.uk/documents/MoT_Wheatsheaf1952.pdf

[Boris]

But isn't that how you get overheating, ie crown exposure even if it's momentary. You wont get it if the crown is covered with water.

 

Sorry, engaged fingers before brain, yes I meant a shorter exposure rather than a prolonged one.

[Jenny Emily]

I've seen fusible plugs let go a couple of times over the years. They are there as a safety device, so if they go they are doing their job preventing a much worse accident. With traction engines the main reason they blow is forgetting which way the water slops when going downhill - on really steep hills I have reversed traction engines down before now to prevent trouble.

 

A fusible plug can partially melt. Over time they seem to slowly waste away anyway such that the one removed from my Father's Garrett after many seasons' use was on the verge of blowing despite having never actually been abused. What worries me is the engine owner at one rally who boasted that his fusible plug was in fact nothing more than a plain bolt and that it was in no risk of melting as a result. He seriously missed the point of why there is supposed to be one, and I made sure I never got too close to him on the subsequent road run.

[roythebus]

There was a case in the USA where a traction engine fusible plug was welded in place!! The boiler exploded with subsequent loss of life.

[PhilH]

Over time they seem to slowly waste away anyway such that the one removed from my Father's Garrett after many seasons' use was on the verge of blowing despite having never actually been abused.

 

Surely this would be due to the normal scouring action of boiler water (or rather the rubbish in the water) which, given time will eat through most things known to man, especially if either boiler treatment is not regularly added or water which hasn't been through reverse osmosis is used.