73096

Just seen the sad state of 73096 following the MHR Spring gala. The photo looks to show that the LH cylinder "primed" as the front of the whole cylinder casing seems to have been pushed off forcefully.
Without prejudging what happened in this case I am interested in how superheated steam locos can prime since temperature and pressure in the superheater tubes and the position of the regulator valve in the dome would surely prevent any large quantity of water travelling from boiler to cylinder, so if any experienced footplate crew or engineer can explain the phenomenon I'd be grateful.
And as this is a forum perhaps also to speculate on the cause of the problem that this magnificent loco has befallen?

 

Why would someone read through an entire thread about the gala when they just want to talk about one loco? It's the 73096 discussion in the gala thread that is out of place, not the post here.

 

ok thanks Sidmouth - I have now read the gala thread and the consensus seems to be that it was not a priming incident but related to a core plug coming adrift and the piston stroke forcing it against the cylinder head and with nowhere to go, something had to give. and it did.
ok two questions for discussion.
Q1 Can this country still offer facilities to re-cast a loco cylinder or do we yet again have to look to China or Germany to find someone still able to do this?
Q2 I am still intrerested in how superheated engines can prime so catastrophically Because they did sometimes even if not in this case. I would have thought that boiler water entering the steam pipes would simply saturate the superheated steam without condensing? (bearing in mind it is probably at or above boiling point anyway)

 

Deleted.

 

With regard to having the cylindes cast, yes, there are plenty of companies ( well, several!) who could do it. They aren't huge castings.
As for priming and superheaters, when you pick up the water it is just that, water. It hasn't been turned into steam and to do so you need to put a lot more heat into it. The latent heat of vapourisation if you remember your physics. So, it is very unlikely to be boiled off whilst going through the superheater tubes. 60007 is fitted with a pyrometer and, when working hard on the NYMR, you can get the superheater steam temperature up to 330-340°C. If you pick up the water that temperature will drop like a stone to about 200°C which is the saturation temperature of the steam. In fact, often, the first sign you get that it is starting to pick up water is to see the temperature gauge start to drop.

 

at least no one was hurt during this incident ,for that we have to be thankfull, imagine if the plug had let go when entering a packed platform.
i would expect that this is a job that will have to be done getting a cyinder cast and then the machineing will be an expensive job but as the engine only has a short ish time left on its ticket 3 years? will it be worth it financially is there a spare standard cylinder that could be used and a new one cast at a later date during its next ten year overhaul there are two that are out of use at the moment, camalot and the five at the ELR could either of these give up one of their cylinder s for a short time till the five comes out of ticket or what other standards used the same casting

 

With regards fitting a new cylinder to her from a stored locomotive. seeing as no two locomotives are the same would that say that they may not fit as the machining tolerences would be different

 

This is the second time in preservation that this kind of accident has happened (the other being 6201), so my question is, how are the core plugs secured in position? Is there a case for improving the security of their retention?

 

Can't see either of these owners agreeing to give up a cylinder, especiallly as the ELR (actually GCR now) example is getting close to completion, anbd Camelot may be fast tracked by the Bluebell. 73096 is of course the subject of an agreement with its owner, and one would imagine that such damage would have to be rectified before it is returned to that owner. I would imagine that owner is the reason for the hypersensitivity that seems to be surrounding this incident!

 

I'd stop worrying about getting a new casting made and machined. It's the time and money it will cost to get a pattern for the casting made, if one doesn't exist. These are very complicated and time consuming things to make.

 

I believe mr. rileys locos have been modified!

 

Martin: Did the SVR volunteer pattern maker (Brian) make the pattern for casting the new cylinder for "Taw Valley" by any chance? ( see my link earlier down this topic for photos of said pattern, quite a substantial piece of kit)

Regards

46118

 

hire that man!

 

Darren:

One can appreciate your concern but enough is enough as it,s not the only loco in the world.

Please stop flogging a dead horse, pack it in will you for it does you no credit doing this.

As said ,I appreciate what you have said, another 5 is due out soon , transfer your allegance to that.

Regards
Chris

 

I think that a cylinder pattern & cores is probably a bit big for B'north pattern shop.

However I wonder if by any chance there are common features with an 82xxx tank cylinders..................................

 

I can think of at least one other. And I seem to remember there was a series of them at one time.