1014 County of Glamorgan

The Super D has flangeless wheels on the third axle. LNWR design was the way forward.

 

There are those that like the S160 and those that don't. Unfortunately, it appears that the latter had the deciding vote. Me? I'd have a fleet of them, even though they are American!

 

My understanding was that the owning group intended to go 'mainline'. As 1014 still has it's Hall cylinders but 3" larger driving wheels it will be actually poorer than a Hall in tractive effort terms. The whole reason that the Counties were pressed to 280/250 psi was to raise the T.E. whilst keeping the same cylinder dia. Hence my point that it will be an inferior machine.
Ray.

 

I wasn't intending to revive the flangeless driver debate, merely reporting what I was told . I think that the statement that the NYMR has operated more 8-coupled engines than any other line is questionable - we've had the Q6 for many years and various GW types and 13809 at times, but I would think that the SVR (48773 and 2857 plus visitors) have run a lot more miles - and possibly the P & DSR and WSR as well.

 

How about 63395, 63460, 4277, 5224, 2253, 6046, 48431, 49395, 53809, & 2807 for eight coupled locos on the NYMR? Combined they have clocked up an awful lot of miles (182307 to the end of 2014) and I doubt anyone can beat this total. Add to this 3672, 90775, 92214 & 92220 for ten-coupled. In fact, I think that the only example of eight-coupled that we still haven't had is An Austerity 2-8-0. Oh, and a 72XX.

 

So is a Hall an Inferior machine to a 28xx because it has a lower tractive effort ? in practice that 3 inch wheel difference translates to a couple of minutes longer before using the reverser...
Probably more important is a bit of extra tinkering to ensure this mongrel boiler steams well...

 

The impression people seem to have is that 1014 will run at 225psi. I don't think anything definite has been forthcoming from the GWS yet. Obviously a full re-staying of the 8F firebox will be necessary, if it hasn't already been completed. Surely with modern technology and top quality materials, the boiler could be pressed to 250 psi? After all, isn't hydraulic boiler testing carried out at a pressure considerably higher than the normal working pressure - and in safety?

 

Surely the Margin of error is there to allow for the ongoing deterioration of the boiler from 'new' But in the abcence of sophisticated analysis one suspects that Locomotive boilers are a little over spec Even so The Firebox is what it is - you cant enhance the material thats already there and whether a denser staying within an existing stay pattern is possible seems a bit hopeful and whatever specc the rest of the boiler is made to - the weakest part of the whole assembly dictates whats allowable. Maybe they will get approval for 230psi.
Whatever the out come the Clan People will be interested as they would like higher than 225psi but dont want to deviate from the 'approved' design...

 

Maybe the County's cylinders could be bored out to achieve the same tractive effort as the 250psi specification?

 

Must admit, that's more than I remembered, (how could I forget 2253?) but 48773 has run over 100,000 miles on the SVR, I think, and 2857 has done quite a few as well. After that, though, its a question of how many miles visitors have clocked up. Same with the WSR - 53808 and 3850 have clocked up quite a lot, its a question of what the visitors have done.

 

Out of interest, and since it has been mentioned, what safety margin would normally be used in a hydraulic test? It is something I have often wondered about.

Dave

 

Usually working pressure plus 50%

 

Cylinders were routinely bored out. I tried to find out scrapping thickness for wheels and maximum bore for cylinders used by Swindon, and, if I found the correct numbers, with both at the limit the calculated tractive effort for any given class was roughly 10% greater than the book value. It seems to me people get needlessly excited by such numbers.

 

Depends which school of thought you apply. The Factories Act required a hydraulic test to 1.5 times working pressure although is no longer applicable. However, the railways applied a different and lower formula and this is recommended practice from the ORR/HRA. In my experience, Boiler Inspectors tend to continue with the 1.5 times for ex land based boilers, industrial locos and traction engines, etc because that is what they were originally tested to but use the lower standard when testing ex main line locos because that is what they were originally tested to.

 

Thanks for the replies. When working I was involved with pressure vessels, but not with the insurance tests themselves, so that's interesting.

Dave

 

From memory, in recent history, the Patriot has the option offered by the boiler insurers, to go to 225psi, without alteration of the stay pattern, maybe the stay material will have to change ? but the original boiler was designed and pressed to 200 psi working pressure. As for the County, I am aware that the increase from 225 to 250 psi would impose a greater stress ratio, but an increase say to 240 would appear possible, if not 250psi.

 

Haha Andalfi i was just about to say the same thing!

 

Thanks for that Chaps, very interesting....

 

I reckon that going to 240 psig plus 0.5in on the cylinder dia gives the equivalent of 250 psig. Whether this is possible or not I have no idea.

 

While there is some uncertainty as to why the Counties were designed at all, the choice of 280 psi (originally) was surely mainly for the sake of getting about the same TE as a Castle with the same cylinders as Halls etc rather than for the small improvement over 225 or 250 psi in thermal efficiency. Therefore it could be argued that the new build with probably only 225 psi, possibly slightly more, won't be a proper County.