Tornado

Possibly. Even probably, but only if there was a hydraulicing situation. Priming doesn't always result in this. If it did there would be many more broken cylinders.

 

They may well have operated but if the priming is severe the relief valves alone will not be sufficient. Opening the drain cocks and shutting the regulator are the first action to be taken.

 

It’s really tempting to answer this from a technical perspective and feed running hare now it’s out of the trap. But I’m going to pass.

I did my fair share of mechanical analysis last time around on broken combo levers. Which incidentally happend to be broadly correct, not that I delighted in that of course.

Poor tornado is having an annus horribilis isn’t she?

I have every confidence that all will be put right by the trust and all will settle down.

Let’s not forget. These are steam engines. They have their moments. Much like all of us.

 

Ok thanks for that but surely steam can be compressed but water can’t?

 

If you can close the regulator. Doesn’t it become very difficult to move?

 

Yes, but if I understand @Steve ‘s point correctly, it is that to damage the combination lever, you would have to transmit a shock back from the valve spindle, and water in the valve chest won’t do that for the reasons he outlines, i.e. water in the inlet side doesn’t get compressed because the volume between the valve heads doesn’t change; and water in the exhaust side has a free path to exit via the blast pipe. It’s why, incidentally, you have drain cocks on the cylinder but not on the valve.

Where priming can cause physical damage is if it gets into the cylinders, but in the worst case that causes damage to cylinder covers and the piston rod, not directly to the combination lever.

Tom

 

Ok thanks Tom

 

I had decided that that is what Steve was saying, but to develop the point, the swing of the combination lever is a lot greater through the drive from the crosshead. Is your point that for there to be some sort of shock through that linkage, it would only be in circumstances which cause the cylinder cover or some other major component failure? Having a quick trawl through such copies of LNER record cards that I have, the only explicit reference to combination lever damage is for 60507 which appears to have been due to a seized middle valve. The A1s seem very prone to cylinders cracking and it may be that collateral damage arising was not recorded.

 

I still get the feeling that the Trust are not being entirely honest with their supporters. They did not make an instant diagnosis of the April problem but said there would be a full investigation. This has taken place but the full results are still not known. For the latest incident they have come to an instant conclusion that it was down to priming.
My own view is that certain senior officials in the Trust have got a bit complacent bordering on arrogance

 

Damaged combination levers is usually down to seized valves.

 

I do tend to agree with you and my feelings goes further back to all those initial problems with the boiler never mind the more recent motion troubles, but at the end of the day it's their locomotive and their supporters and its up to them to manage those as they see fit, although as an outsider looking in 'can do better' springs to my mind.


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Does this mean a new combination lever will have to be cast?

 

I am a supporter, if I wasn’t I don’t think it would be my place to criticise

 

I think it’s a forging rather than a casting. They were talking of being able to straighten it

 

If my memory serves me correctly, forgings can be straightened, because the steel is malleable, whereas castings tend to crack unless treated extremely carefully.

 

Either that or a seized pin within the combination lever. I'm at a loss to think of any other failure mechanism (other than a flaw.)

 

No replacement combination lever was required as I understand it.

 

Catching up on the thread after the statement from the A1 Trust, I'm now pleased to see others and not just the two I've quoted above, also seem to think that the statement from them doesn't quite match up.

What I'm struggling to understand is that if the combination lever was damaged from the priming incident, then why wasn't there any other significant or serious damage to any of the other parts of the motion. In my mind, the combination lever is down on the list of parts of the motion to be damaged from such an incident.

 

Probably because they can't admit their own fallibility...... smacks of arrogance & believe me they are.

Stems from when the thing sat down on the mainline - they blamed hitting something in the 4'....... yes they did - chunks of the middle cylinder - if it'd been anything else, the whole train would've been on its side - took em a long time to admit the loco was broke!!

 

Aren't we all? Well, some of us. We'll probably never know, though.