Returning a Bulleid Merchant Navy to as built condition

I think City of Wells and Tangmere have long since well and truely laid all the old ghosts to rest on the mainline. In fact, I'd suggest that the design is better suited to the mainline now than almost any other, with its lack of oiling points etc.

 

firstly, look at when the orginals were introduced, in war time when the fitting staff were already stretched to breaking point, over the years the concept has been prooved to be sound, i think that someone was to launch an appeal to re build an MN into its original air smoothed form it would have to be done keeping what can be saved, for instance,could the middle cylinder and valve gear could be altered with out replacing componants that are in good condition , things such the oil bath and chain gear could be copied from a light pacific and modern seals and pins etc would would remove the problems associated with the valve gear

 

Stewie griffin, sticking a tender behind an austerty and calling it a black motor is currently happening at the MHR to no10 douglas.

 

Stewie: There are somewhere printed some engine "out of service" figures for the unrebuilt engines, I cannot find them, but I dont have particularly much literature on "Southern". I dont have the Winkworth book, but I do possess a copy of "Bulleid Power- the Merchant Navy Class" by A J Fry, and in that book the author provides a platform for railwaymen of that era to recount their experiences with the unrebuilt MNs. Two gents featured are Peter Christmas and Russ Coffin. There is also a chapter in the book entitled "A Fitter's Nightmare?". In fairness it is not all bad!
I suspect many of the teething problems stemmed from the fact that these were innovative engines, coming into service in wartime. Hardly the best time to be intoducing locomotives with many new features.
Russ Coffin comments about the rebuilt engines: "...certainly more conventional to look at, but never seemed to run as freely as the original members of the class. The riding was not so good, but the foreward visibility was vastly improved. The conventional reverser was not universally liked..etc....the disposal of the engine was eased by the installation of a rocking and tip-up grate..."

Found them! Here are the Southern's figures produced in support of rebuilding : An average of 62 days out of service for running repairs and examinations in 1952, compared with 49 days for a Lord Nelson. Comparable costs of repairs per engine mile were 14 pence for the MNs, 11 pence for the Lord Nelson class, and 7 pence for the LNER A1 class. With the rebuilding the savings in coal and water were 10% and 8% , along with reduced costs for maintenance. Coal and water figures are surprising given that it was the same boiler/firebox, but hey thats statisitics for you.

 

I know, don't get me started on that one...!

I think that is one of the key issues; the MN's were very much a product of the environment they were produced in, with potentially substandard materials used and an almost complete lack of anything other than the most essential maintenance. I do wonder to what extent were running sheds still playing 'catch up' on the maintenance issues on what was still a more advanced loco than most of those available post-war, which may have artificially skewed the statistics?

I suspect that a lot of the discrepancy with the coal and water figures may be explainable by the vagaries of the steam reverser. As has previously been said they had the potential to be temperamental in the extreme, whereas the screw reverser could be adjusted finely and so allow for much more economical working than a steam reverser that is creeping all over the place. However, given modern seals and a concerted effort on ensuring the proper lubrication preservation has shown that these reversers can be made almost as reliable as the alternative.

 

MN's had larger cylinders too. I am 100% certain that the valve gear was the same for both MN and WC/BB classes. I have seen an number of drawings and they have been annotated simply as Bulleid chain driven gear with no other qualification as to MN or BB/WC.

 

Keep on like this and you'll get on my Christmas card list.

 

I've only ever driven an unrebuilt Light Pacific once so I can't comment specifically on them but I've plenty of experience of using steam reversers. The UK ones are all much of a muchness and the main drawback is that you cannot finesse them. I've never really experienced any problem with creep but I guess that this depends on the condition of the cataract valve. With a steam reverse, you tend to put it somewhere near where you want it and leave it there because any attempt at fine adjustment is futile and the nearer you get to mid gear, the greater the chance of putting it into reverse in making an adjustment. This will almost certainly account for the poor fuel and water economy record.
In another post, Bulleid Pacific has suggested that a Morse chain won't stretch. Well, I've never yet come across a chain of any sort that didn't stretch due to wear, even when they are running in perfect conditions. If a Morse chain didn't stretch, then it would have superseded a lot of other chains in a multitude of applications.
I can see the sense in un-rebuilding a Merchant Navy to provide a representation of a lost locomotive, just like I can see the sense in building an A1, a County, G5 or whatever. However, it really ought to be a warts and all project and not one that compromises, except perhaps in terms of seals and materials specs where the original is no longer available. It is only by doing this that we can learn more of the reality. After all, it is over fifty years since one last ran and anyone who had anything to do with them must be well into his seventies. Time colours everyone's memories and what was a curse then can be looked on with great affection, now.

 

Doesn't Tangmere have a Steam Reverser?

 

Don't all the unrebuilts?

 

If an owner and their friends want to put a MN back to production Original spec. Let them.
You are entitiled to your opinion.

 

steve - yes she does , as do all un rebuilts, but they differ between engines, for instance on 34105, it was a bit on the slow side, and could be controled fairly easily by the driver , when we had 257 squadron visit, my driver almost got caught out by it, it was a lot faster in operating than what he was used to i havnt been on either of the other un rebuilds so i cant say if this was just a one off difference between 2 engines or if the later builds had a different steam reverser

 

Fair enough. Its hard to believe that the actual links in the chain can stretch that much, I'd have said it would be the securing pins that are most vulnerable to distortion. However, I'm willing to be turned into the correct direction.

 

Motorcycle drive chains need regular adjustment to take up the slack. They are subjected to all that dust and debris from the road, mixed with lube creates the perfect abrasive paste, they wear and stretch.

I think that the number of links is the problem, if each link stretches just 0.001" then 100 links will have increased the length of the chain by 0.1" or about 2.5mm, an automatic tensioner would help.

 

It's nothing to do with stretch of links or distortion of pins; it is simply down to wear in the pins and links. You don't need too much wear to put a chain out of pitch.

 

twr12: Sorry, I should have made it clear that I do not have an opinion on this issue. As you rightly say, if an individual or group can put up the cash, then they can do as they wish.

The remarks I quoted there were from "British Pacific Locomotives" by Cecil J Allen, and I should have made that clear. Apologies.

Regards

46118

 

IF this does come to fruition (and sadly I doubt it will) then wouldn't it be great to turn it out with the original style of cladding? Yes I know about the exhaust drift problem, but a real head-turner, in a similar way to LNER 10000. Of course you could always fit a different draughting arrangement, like the Geisel fitted on City of Wells

 

I think you mean Giesl, Sheff. Geisel is German for "hostage" and is pronounced as in "guys"

 

Ok - I can't spell deasel ether

 

Naiss wan Sheff