7027 Thornbury Castle

Name me one Black Five in preservation fitted with an 8F boiler. Name one.

 

You don't know your boilers. The front barrel on an 8F boiler is about a foot shorter than the front barrel on a Class 5. 8F boilers are made from bog standard boiler plate, whereas Class 5 boilers are made from thinner alloy steel.

 

Can't name an 8f with a Black 5 boiler either, point missed.

 

No, not missed. You've made a comment about how you'd place an 8F boiler onto a Black 5 or vice versa, despite this never having been done in service or preservation to date.

 

If no Black 5's existed, or you only had a chassis and you wanted to recreate/ restore one you would need a new boiler £ 0.5 Million...
- Cost of changing the front barrel and restoring the boiler of an 8f ? £ 0.2 million? ... oh and it might be a little heavier than a true original...

Clearly the pragmatic is less important than the pedantic...

 

The scenario is Hypothetical and the premise is there are no Black 5's
Because there are dozens of both extant in 'real life' there has never been the ' need '
Another Hypothetical you might find a bit easier to Imagine ; there are a dozen A3 Pacifics including one or two that have only had so much as wirebrush and dettol since they were rescued from Doncaster , and someone decides that a V2 (cause hypothetically they all got scrapped)
would be a good thing to recreate an example of ; New Build Boiler ? Shorten an A3 one.? ..
It could be done ( even if there is an argument that it shouldnt be)

 

And therein lies the challenge for preservation ethics. Is such a scheme truly a preservation scheme, or is it some kind of engineering butcher's shop?

The arguments about 7027 and 4709 have been done to death, and few will change their position now. But its far from clear to me that the recreation of an extinct class using mix 'n match components that sort of look like the real thing is actually preservation, or that it really helps us understand what was previously there. Given the way that Churchward's designs relied on common parts, I'm far from clear what this type of recreation of a 47xx adds to our real understanding of GJC, GWR or heavy freight locomotives - the evolutionary niche of the 47xxs is simply too small given the other classes that do survive and allow us to understand how steam evolved. And, thinking of the test case, I'd also say the same about the Black 5 - we have representation of Stanier's designs (Jubilees, Mogul and 8Fs), other grouping era mixed traffic 4-6-0s, and the Riddles 5MT evolutions of the Black 5, so have enough to represent and understand what was happening at this time, even if not the specific representative.

But I'd struggle to take the same view of a similar engineering approach to a broad gauge replica, or something from the pre-Churchward GWR. That's not about the donor, but about the recipient of the donation.

 

Hasn't the overhaul of 1363 already started ages back and was then stopped as more work was required than envisaged, I assume its now restarting instead of the King which makes perfect sense. As for the delays in 1466 it is my understanding there are reasons its taking so long (and why the overhaul has been rather nomadic) go beyond its condition, but as I have only heard from a single source I will not repeat here.

Speaking of GWS overhauls what the heck has happened with 7202, must be in the running for one of the longest running restorations ever undertaken, I recall that when I used to visit in the 80's the Heavy Freight Group (Mob) were really active, has than changed now?

But one which is entirely feasible for what is a size of locomotive which perfectly fits the need/aspiration to have a tender engine on site at Didcot.

Indeed, but as the 47xx group have nothing to do with the GWS, obviously not relevant

 

Indeed, perhaps to appeal to their strange model railwayesque bodging vision of 'preservation' someone should try and get it into their head to convert 7027 to Manorbier Castle.....

 

I have no desire to get into what should or not happen to this specific loco other than to ask where is all the money going to come from for many of these ideas mooted (so lets stick with 7027).
I have a good (I suspect many would say very good) RPI linked company pension. We both receive full state pension and my wife has a small private pension. Maybe in times past I may have thought of supporting a project like this. But in the 10 years since I retired I have never really worried about money and Covid of course boosted our savings when there was nothing to spend money on. However now seeing that last month outgoings were only £200 less than incomings where would I morally find the money to support any railway project currently. Remember this is during the summer with no heating use, on a fixed rate that until December avoids two Ofgem increases.
It may be a fine project to restore 7027, if it was even for sale, but where is the money coming from?
This of course not only applies to this project but all locos and HR in general.

 

John Minchin passed away some time ago and there doesn't seem to be much left of the HFM.

Replacing the backhead is no small job and once examined the boiler may need a lot more major work.

That's clearly not true. Just examine their website.

 

I used to work with someone whom I think was involved with 7202 years ago - late 80s/early 90s?

 

Like A3 and A4 boilers on LNER Pacifics?

I think preservation is one of those words people use the way they choose. Arguably there's not much in the heritage railway game (much more accurate description) that fits very well with a dictionary definition of preservation. Certainly not main line running, nor building of extra facilities, or even restoration of locomotives, buildings or stock to earlier condition than when they came out of use.

 

So, how significant is the 47xx and were we to build a replica what might we learn?

 

A higher pressure design would mean a new boiler! There's also another big difference between a no 7 and no 8 boiler. 7027's no 8 has flues for 21 superheater elements, whereas the no. 7 had either 4 or 6 superheater elements (according to Wikipedia). What will they do with 4709? Will 4709 have 21 elements or just 4 or 6? The latter would reduce the heating surface from standard.

 

It's a Belpaire firebox and eventual cracking of these is pretty much par for the course. There wouldn't be many locos running today if every one suffering from this was set aside in the 'too hard to do/too expensive' box.

 

Yes, it would, and to a modfied design.
Trying to put the right no of flues/ tubes for a No 7 in a no 8 makes no sense - if an existing boiler configuration steams well ' it aint broke'.
A compromise in the name of ... whatever... would be to go back to the original 14 element array, even thenas tube plates waste away and flues/tubes need replacing anyway then its not a big deal is it.

 

I think reducing the number of superheater flues increases the heating surface (because the space saved is used for extra smoke tubes).

Basically, increasing the amount of superheater elements decreases the steaming rate (because the heating surface goes down) but enhances the steam temperature which for an engine working at sustained high output more than compensates. For a loco trundling up and down a demonstration line, a superheater is far more trouble than it is worth.

Tom

 

And if there were a Spare No 8 boiler discovered at the back of a shed, rather than from an active resotration, this would be a more reasonable proposition. However..... and perhaps the selection of an 8F boiler is also unfortunate in this conversation, too...