Unrebuilding a Merchant Navy

[Siqulme]

Good evening,
Over the last few months a team have been setting up a society to backdate 35011 General Steam Navigation. I thought it might be worth posting the latest update from the project to this fourm as I thought it would be of some interest as unrebuilding a MN has something that has been talked about since Barry.

http://35011gsn.weebly.com/news/january-update

Would be interested to hear what you guys think about the project.

 

[4-COR 3142]

Sounds an interesting project but I would imagine fairly (read VERY) expensive?

From a cost and reliability point of view are you also considering - if its actually possible - to just fit the original pattern of streamlining back onto the rebuilt loco?

 

[CarltonA]

If it's just a matter of fitting "air smoothed casing" (not streamlining) it would not be so expensive to do. Going for a full "unrebuild" including oil baths and chain drive would of course be very costly. Why do this to an improved design though, especially when there are several "spam can" versions of the light pacific in existence? You would end up with an unimproved loco surely. The originals had quite a few flaws which are well documented.

 

[TheEdge]

I can see both sides to this one. The Southern Pacifics were rebuilt for a good reason but then there are no remaining "original" Merchant Navy examples.

Although like CarltonA says the cost, and I imagine technical work, to reinstate the chain driven gear would be enourmous. It would seem fairly pointless to only reinstate the streamline casing as, unlike the Duchess, the de-streamlining was a fairly significant rebuilt.

That being said, good luck to them. I'll be happy just to see one less ex-Barry condition loco...

 

[E&W Lucas]

Good evening,
Over the last few months a team have been setting up a society to backdate 35011 General Steam Navigation. I thought it might be worth posting the latest update from the project to this fourm as I thought it would be of some interest as unrebuilding a MN has something that has been talked about since Barry.

http://35011gsn.weebly.com/news/january-update

Would be interested to hear what you guys think about the project.

Can you tell us some more about who is behind this, experience etc please?
It's very easy to float an idea online, much harder to make things happen on the ground, or rails at least.

I principle I'm very interested in this. Very familiar with the smaller Bulleids, both modified and otherwise, and understand the technical detail of what is required to "unmodify" one.

Not a loco that's going to be much use on a preserved line. Simply too big and heavy. It would be interesting to see if mainline approval could be gained for a re - specified crank axle, which would be at the core of a unrebuild project.

 

[MarkyT]

The chain drive for the miniature valve gear was troublesome I understand, but that was a compromise by Bullied who wanted a higher precision geartrain or shaft mechanism but couldn't justify the cost and resources for casting and machining of these in wartime conditions. A more radical rebuild could replace the chain with a completely redesigned modern linkage aimed at reliability whilst fully recreating the appearance of the original, ie with no external valve gear visible. No doubt a lot of work would be involved in developing and getting such new features approved, but perhaps little more than having to recreate the original design from scratch and certainly no more than the P2 project is attempting with their modified Lentz valve gear proposal.

 

[E&W Lucas]

The chain drive for the miniature valve gear was troublesome I understand, but that was a compromise by Bullied who wanted a higher precision geartrain or shaft mechanism but couldn't justify the cost and resources for casting and machining of these in wartime conditions.

The MNs were rebuilt as a result of the Crewekerne incident, when a crank axle failed. IIRC, the materials were found to be suspect.

The chain drive suffered from poor quality wartime materials. The chains stretched, throwing the valve events out of sync. The system works fine with modern materials.

 

[Siqulme]

If it's just a matter of fitting "air smoothed casing" (not streamlining) it would not be so expensive to do. Going for a full "unrebuild" including oil baths and chain drive would of course be very costly. Why do this to an improved design though, especially when there are several "spam can" versions of the light pacific in existence? You would end up with an unimproved loco surely. The originals had quite a few flaws which are well documented.

With Port Line, Canadian Pacific, Clan Line, P&O and potentially British India Line the amount of rebuilt Merchant Navys out weighs the demend so it makes sense that to restore GSN to her as built condition will givea much needed unique selling point to get the money and support.

(Not long till 06 is in steam bet your excited)

Can you tell us some more about who is behind this, experience etc please?

There Nat Pres thread mentioned that members of the team were involved in the restoration/overhaul of 35005, 35027 and 34007. They have a fairly active social media platform so its worth checking that out.

 

[341o2]

The MNs were rebuilt as a result of the Crewekerne incident, when a crank axle failed. IIRC, the materials were found to be suspect.

The chain drive suffered from poor quality wartime materials. The chains stretched, throwing the valve events out of sync. The system works fine with modern materials.

I understand that the Crewkerne incident was not the major force behind rebuilding.

firstly, there was the 1948 locomotive exchanges. The Southern crews put up a magnificent display, but at the price of being at the bottom of the tables regarding coal and water consumption.

Between 1952 and 1954 no 35022 was sent to the London midland region for testing, in part at Rugby, where the problems were really felt. The locomotive produced inconsistent and sometimes theoretically impossible outputs. Oil from the bath contaminated the rollers, leading to a reluctance to test the locomotive to its limits for fear of damage to both the loco and the test plant.

The steam reversing gear - another detail altered in the rebulids to a LMS style screw reverser - tended to creep, not enough to matter enough in everyday service, but hampered accurate testing. Eventuaslly clamps were fabricated to hold it in place.

The overall conclusion was that the class were "most efficient and capable,but one that is relitively uneconomical"

Meanwhile, on the SR there was a new order of locomotive bosses. In particular, C S Cocks, a Bulleid man was replaced by R J Jarvis, an Ivatt man, with emphasis on simplicity. Bulleid defended his design, but the diesel revolution had now starrted, the demise of steam in sight, and there was no need to design an advanced steam locomotive of the future.

the rebuilding programme, with Jarvis designing the work was halted in June 1961 due to the short life expectancy for steam.

 

[MarkyT]

The steam reversing gear - another detail altered in the rebulids to a LMS style screw reverser - tended to creep, not enough to matter enough in everyday service, but hampered accurate testing.

As something that presumably wouldn't affect the outward appearance of the locomotive, the reverser mechanism need not be converted back to steam actuation in an unrebuilding although would need redesigning as part of a replacement valve gear, which being a miniature version of the Walschaerts mechanism, should be fairly lightweight and easy to adjust by manual force and mechanical linkage.

The overall conclusion was that the class were "most efficient and capable,but one that is relitively uneconomical"

Note the interesting historic use of the word 'efficient' there. How could a loco be both efficient and uneconomical (with respect to coal and water presumably)? In that old usage efficient really just meant capable and reliable, being able to do the job etc, whilst today a measure of efficiency requires a detailed understanding of all inputs and outputs.

Bulleid defended his design, but the diesel revolution had now starrted, the demise of steam in sight, and there was no need to design an advanced steam locomotive of the future.

Once his turf burner project had been abandoned, Bullied oversaw the very successful and rapid dieselisation programme in the Republic of Ireland.

 

[E&W Lucas]

I understand that the Crewkerne incident was not the major force behind rebuilding.

firstly, there was the 1948 locomotive exchanges. The Southern crews put up a magnificent display, but at the price of being at the bottom of the tables regarding coal and water consumption.

Between 1952 and 1954 no 35022 was sent to the London midland region for testing, in part at Rugby, where the problems were really felt. The locomotive produced inconsistent and sometimes theoretically impossible outputs. Oil from the bath contaminated the rollers, leading to a reluctance to test the locomotive to its limits for fear of damage to both the loco and the test plant.

The steam reversing gear - another detail altered in the rebulids to a LMS style screw reverser - tended to creep, not enough to matter enough in everyday service, but hampered accurate testing. Eventuaslly clamps were fabricated to hold it in place.

The overall conclusion was that the class were "most efficient and capable,but one that is relitively uneconomical"

Meanwhile, on the SR there was a new order of locomotive bosses. In particular, C S Cocks, a Bulleid man was replaced by R J Jarvis, an Ivatt man, with emphasis on simplicity. Bulleid defended his design, but the diesel revolution had now starrted, the demise of steam in sight, and there was no need to design an advanced steam locomotive of the future.

the rebuilding programme, with Jarvis designing the work was halted in June 1961 due to the short life expectancy for steam.

Have you read all that somewhere?
The whole class was withdrawn as a result of Crewekerne. Other locos were found to be on the way to suffering the same failure, which it was incredibly lucky not to have caused a mass casualty derailment.

Steam reverser creep is not confined to Bulleid locos. It's usually caused by oil leaking in the hydraulic lock . They are incredibly simple and proven mechanisms. Something is leaking - austerity materials. They are no more troublesome than any other steam reverser in my experience.
The locos weren't built to be economical - they were built to be able to burn any dross that was fed into them; something they do admirably. The rebuilding did not affect the boiler in any way. If anything, they became slightly less efficient, as the loss between regulator and steam chest is higher on the modified locos.

Politics no doubt played a part, but something had to be done with the class after the accident.
--- old post above --- --- new post below ---

As something that presumably wouldn't affect the outward appearance of the locomotive, the reverser mechanism need not be converted back to steam actuation in an unrebuilding .

If you're going to do something, do it properly.
--- old post above --- --- new post below ---

which being a miniature version of the Walschaerts mechanism, should be fairly lightweight and easy to adjust by manual force and mechanical linkage.

That's got more to do with the valves themselves, than the valve gear.

 

[colchesterken]

I would have thought the way to go forward is like the tornado project, rebuild it as they would have done if they were building the next in series
I read someware that the oil bath could be redesigned not to leak. Improve the boiler to modern standards, any improvements to steaming ( as was done with the Duke ), then we will see what could have been done if development had continued
So often we ( UK PLC ) fail to see things through, Tilting trains, we invented them then gave up..Jet engine invented by us perfected by Americans

 

[MarkyT]

I would have thought the way to go forward is like the tornado project, rebuild it as they would have done if they were building the next in series
I read someware that the oil bath could be redesigned not to leak. Improve the boiler to modern standards, any improvements to steaming ( as was done with the Duke ), then we will see what could have been done if development had continued
So often we ( UK PLC ) fail to see things through, Tilting trains, we invented them then gave up..Jet engine invented by us perfected by Americans

That was what I was trying to suggest before really. With a replacement gear train drive to the valve gear (fully enclosed in itself with built in lubrication) perhaps the oil bath could be dispensed with entirely. All bearings replaced by rollers, double Kylchap exhaust in place of the big Lemaitre (would be practically invisible behind the spam can casing anyway except from above, and some subtle changes to the casing at the front to improve smoke lifting (which always seems particularly poor on Tangmere when I've seen it at speed and was noted as detrimental to the driver's forward visibility in the Wootton Bassett incident report).

Apologies to the Southern purists !

 

[Spamcan81]

Have you read all that somewhere?
The whole class was withdrawn as a result of Crewekerne. Other locos were found to be on the way to suffering the same failure, which it was incredibly lucky not to have caused a mass casualty derailment.

Steam reverser creep is not confined to Bulleid locos. It's usually caused by oil leaking in the hydraulic lock . They are incredibly simple and proven mechanisms. Something is leaking - austerity materials. They are no more troublesome than any other steam reverser in my experience.
The locos weren't built to be economical - they were built to be able to burn any dross that was fed into them; something they do admirably. The rebuilding did not affect the boiler in any way. If anything, they became slightly less efficient, as the loss between regulator and steam chest is higher on the modified locos.

Politics no doubt played a part, but something had to be done with the class after the accident.
--- old post above --- --- new post below ---


If you're going to do something, do it properly.
--- old post above --- --- new post below ---


That's got more to do with the valves themselves, than the valve gear.

The whole class may have been withdrawn after Crewkerne but not to be rebuilt, the accident was not the driving force behind the rebuilding programme.
--- old post above --- --- new post below ---

Good evening,
Over the last few months a team have been setting up a society to backdate 35011 General Steam Navigation. I thought it might be worth posting the latest update from the project to this fourm as I thought it would be of some interest as unrebuilding a MN has something that has been talked about since Barry.

http://35011gsn.weebly.com/news/january-update

Would be interested to hear what you guys think about the project.

Go for it. It has to be done. An original Merchant would help fill a gap in the Bulleid story and is the holy grail for many Bulleid admirers. You can't have too many Flat Tops.

 

[341o2]

I've misquoted the official report following the tests carried out on 35022. "efficient" should read "effective"

a new build would be most interesting, particularly if it would be as originally designed - a 2-8-2

smoke problems, which were referred to in the trial following the Lewisham disaster could have been solved by fitting Giesl ejectors. No 34064 was indeed thus fitted in BR days, and reckoned to be one of the best pacifics. A scheme to equip some 20 locos was put forward in 1963, but BR bosses said no more expenditure on steam.

34092 City of Wells is thus equipped

The Irish situation immediately post war was reminiscent of a heritage line today, apart from the 800 class, the vast majority of the stock was ancient, some to be so run down as to be unuseable.

 

[MarkyT]

I've misquoted the official report following the tests carried out on 35022. "efficient" should read "effective"

OK thanks!

a new build would be most interesting, particularly if it would be as originally designed - a 2-8-2

http://www.bulleidboard.pwp.blueyonder.co.uk/images/dcp/MN_alt_drwg2_w8.jpg

Rather like a second generation P2 then! The Helmholz bogie arrangement proposed for the front driving axle was a great idea for negotiating tight curves, A shame the civil engineer persuaded the company against the idea at the time.

smoke problems, which were referred to in the trial following the Lewisham disaster could have been solved by fitting Giesel ejectors. No 34064 was indeed thus fitted in BR days, and reckoned to be one of the best pacifics. A scheme to equip some 20 locos was put forward in 1963, but BR bosses said no more expenditure on steam.

My dad recalled BR HQ management were somewhat prejudiced against 'foreign' solutions and very reluctant to pay for patent licenses. The Giesl was a post war invention and widely adopted in Austria (home of the inventor) and East Germany. Unlike the Kylchap design it was still subject to patent fees during the last years of steam.

34092 City of Wells is thus equipped

Didn't know that thanks.

I found this picture which illustrates it well:
http://railwells.com/wp-content/uploads/2016/01/IMG_3179-1000-x-750.jpg

Perhaps the long narrow chimney encourages faster smoother airflow around it and with the concealed sloping top of the smokebox that might create sufficient uplift to avoid the smoke's downward drift when coupled with the sharp, more concentrated blasts from the series of small nozzles. Whilst a number of small nozzles certainly creates more surface area in the exhaust jets to entrain more flue gases and draw the fire better than a single conventional blastpipe of equivalent cross-sectional area, like my dad I suspect the Giesl didn't increase that overall cross sectional area, so may not have reduced engine backpressure to the degree a double Kylchap would. That said it would be great to see Wells running fast on the mainline to observe how well the Giesl arrangement performs.

 

[E&W Lucas]

(which always seems particularly poor on Tangmere when I've seen it at speed and was noted as detrimental to the driver's forward visibility in the Wootton Bassett incident report).

Are you sure that wasn't someone trying to generate a smokescreen to try and save their sorry a***?

A competent mainline driver will be in a position to stop at a red, long before he can see it.

Remember, we are used to driving in restricted visibility - fog, etc. It's why route knowledge is necessary.

 

[MarkyT]

Are you sure that wasn't someone trying to generate a smokescreen to try and save their sorry a***?

A competent mainline driver will be in a position to stop at a red, long before he can see it.

Indeed, mainly by responding correctly to previous cautions and warnings received on approach! Mind you I'm still in favour of improving forward visibility as much as reasonably practicable, and I'm sure HSE would agree.

 

[Deepgreen]

Good evening,
Over the last few months a team have been setting up a society to backdate 35011 General Steam Navigation. I thought it might be worth posting the latest update from the project to this fourm as I thought it would be of some interest as unrebuilding a MN has something that has been talked about since Barry.

http://35011gsn.weebly.com/news/january-update

Would be interested to hear what you guys think about the project.

It would be fascinating, at the very least. If the original design were adopted, it would at least look significantly different to the existing light Pacifics with air-smoothing, as the first MN design had a somewhat different front end shape. I believe they also had a tractive effort that was a few thousand pounds higher than the rebuilds, I think owing to the greater weight over the driving wheels and a higher operating boiler pressure. Without a leaking oil bath possibly occasionally contaminating the rail head they might be quite "sure-footed".

 

[E&W Lucas]

It would be fascinating, at the very least. If the original design were adopted, it would at least look significantly different to the existing light Pacifics with air-smoothing, as the first MN design had a somewhat different front end shape. I believe they also had a tractive effort that was a few thousand pounds higher than the rebuilds, I think owing to the greater weight over the driving wheels and a higher operating boiler pressure. Without a leaking oil bath possibly occasionally contaminating the rail head they might be quite "sure-footed".

I don't think anyone will go back to the 280 psi boiler. Even the unmodified light pacifics were downrated to 250. TE isn't particularly significant in its own right with a steam loco. The ability to generate sufficient steam to maintain that power is far more important, and that is where Bulleid's designs excel.

Far, far too much is made of leaking oil baths by those who've never been near one of these locos. There is a definite technique to starting a West Country, and I'm sure the MN's will be similar. They do not appreciate heavy handed driving, and that I'm sure is the cause of the bulk of the slipping that is seen/ reported.

 

[Siqulme]

The February Update went live

http://www.35011gsn.co.uk/news/february-update

Lots of news

 

[markindurham]

Actually, the oil bath shouldn't be an issue with modern sealing techniques - and it wasn't just oil getting on to the rails that was a problem - there were a few fires caused by oil soaking into boiler/steam pipe lagging & being ignited by stray sparks. I do wish the group well; this is another missing part of railway history.

 

[Siqulme]

The oil issue was sorted on the smaller BB/WC class and with modern techniques the team can address many of the problems the MNs had. Should be an interesting project and hopefully one day we would be able line up 4 Bulleid Pacific in the differing conditions

 

[Siqulme]

Latest Update: March

The latest update from the 35011 project featuring the launch of the Whistle fund, our next gala stand, new mugs, working weekend and the latest on the Membership Society.

http://www.35011gsn.co.uk/news
--- old post above --- --- new post below ---
Good evening,

Tonight we need you to help us buy our first part for 35011 by contributing to our whistle fund. The Mid Hants Railway 'Watercress Line' have recently got a new whistle cast for their West Country class locomotive 34105 Swanage and have kindly offered us the chance to cast us a new whistle for 35011 using the same patterns. The whistle will be a two piece cast and cost will be £250. You can contribute as much as you'd like to the whistle fund and you can donate via PayPal on our website and cheque or bank transfer if you get in touch. If every member of this page donated £1 we could buy it 5 times over. We have already raised a significant amount and would love to get the whistle fully funded by the weekend.

http://www.35011gsn.co.uk/sponsoring-35011.html

Thanks for your support

 

[matacaster]

The chain drive for the miniature valve gear was troublesome I understand, but that was a compromise by Bullied who wanted a higher precision geartrain or shaft mechanism but couldn't justify the cost and resources for casting and machining of these in wartime conditions. A more radical rebuild could replace the chain with a completely redesigned modern linkage aimed at reliability whilst fully recreating the appearance of the original, ie with no external valve gear visible. No doubt a lot of work would be involved in developing and getting such new features approved, but perhaps little more than having to recreate the original design from scratch and certainly no more than the P2 project is attempting with their modified Lentz valve gear proposal.

*******************************

I would really like to see a steam locomotive equipped with an innovative state of the art computer-controlled valve gear. New sensors would need to be fitted to the steam locomotive to monitor the various parameters required to maximise the optimum cut-off for any given situation. No conventional directly driven link motion would be fitted. This bullied project could provide a test bed for a superior steam locomotive.

 

[Spamcan81]

It would be fascinating, at the very least. If the original design were adopted, it would at least look significantly different to the existing light Pacifics with air-smoothing, as the first MN design had a somewhat different front end shape. I believe they also had a tractive effort that was a few thousand pounds higher than the rebuilds, I think owing to the greater weight over the driving wheels and a higher operating boiler pressure. Without a leaking oil bath possibly occasionally contaminating the rail head they might be quite "sure-footed".

IIRC 21C11 (35011) did not have the same front end appearance as 21C1 (35001) when built.
Weight on driving wheels is not a factor in calculating tractive effort. That is a function of boiler pressure, cylinder volume and wheel diameter. It does however play a part in determining the adhesion factor.

 

[MarkyT]

*******************************

I would really like to see a steam locomotive equipped with an innovative state of the art computer-controlled valve gear. New sensors would need to be fitted to the steam locomotive to monitor the various parameters required to maximise the optimum cut-off for any given situation. No conventional directly driven link motion would be fitted. This bullied project could provide a test bed for a superior steam locomotive.

A fascinating idea. I have also mused on such things occasionally! A problem is many enthusiasts would be lukewarm about adapting historic designs to incorporate such a novel feature, even if the outward appearance would remain unchanged to a layman. With the P2, the original loco of the series, "Cock of the North", was built with a Lentz valve gear, so that project can at least claim a degree of faithfulness to the original design in that respect. They are going to have to redesign the mechanism to an extent however, as the original proved unsuccessful, and the remainder of the class was built with Gresleys's more conventional (for the LNER) two to one conjugated gear, with "Cock of the North" also being modified.

 

[matacaster]

A fascinating idea. I have also mused on such things occasionally! A problem is many enthusiasts would be lukewarm about adapting historic designs to incorporate such a novel feature, even if the outward appearance would remain unchanged to a layman. With the P2, the original loco of the series, "Cock of the North", was built with a Lentz valve gear, so that project can at least claim a degree of faithfulness to the original design in that respect. They are going to have to redesign the mechanism to an extent however, as the original proved unsuccessful, and the remainder of the class was built with Gresleys's more conventional (for the LNER) two to one conjugated gear, with "Cock of the North" also being modified.

From a sensible h&s aspect, i think main line steam locos should be fitted with a pair of front and rear facing cameras including video recording. These could be so located as to be virtually invisible and are cheap nowadays. The reason is the relatively poor forward vision from a steam loco cab the video recording assisting should an incident occur.

Off topic
Any road vehicle where vision is restricted like hgvs, some vans, buses etc should also be so fitted."If you can't see my mirrors I can't see you" is NO defence. A competent lawyer ought to be able to get serious compensationshould an accident occur, particularly while reversing.

 

[MarkyT]

From a sensible h&s aspect, i think main line steam locos should be fitted with a pair of front and rear facing cameras including video recording. These could be so located as to be virtually invisible and are cheap nowadays. The reason is the relatively poor forward vision from a steam loco cab the video recording assisting should an incident occur.

Cameras could be concealed in something that looks like an old school metal lamp casing. A Gresley corridor tender could hide a camera discreetly behind the porthole window at rear. Running backwards with large full height tenders is the biggest concern in my view as crews have to lean right out to see anything at all especially on straight track. I noticed this with Tornado running tender first on the WSR. Approaching me was this massive slab of green metal. Apart from it not being particulaly photogenic from that angle I realised I couldn't actually see the crew at all, so I assumed they probably couldn't see me or equally get a good long view of approaching signals (thus needing exceptionally good route knowledge to judge exactly where to look out to catch a fleeting glimpse of them!). And especially not other unexpected obstructions like livestock suddenly appearing on the track. I know on most heritage lines speed is limited to 25MPH but it did strike me as a particular risk.

 

[matacaster]

Cameras could be concealed in something that looks like an old school metal lamp casing. A Gresley corridor tender could hide a camera discreetly behind the porthole window at rear. Running backwards with large full height tenders is the biggest concern in my view as crews have to lean right out to see anything at all especially on straight track. I noticed this with Tornado running tender first on the WSR. Approaching me was this massive slab of green metal. Apart from it not being particulaly photogenic from that angle I realised I couldn't actually see the crew at all, so I assumed they probably couldn't see me or equally get a good long view of approaching signals (thus needing exceptionally good route knowledge to judge exactly where to look out to catch a fleeting glimpse of them!). And especially not other unexpected obstructions like livestock suddenly appearing on the track. I know on most heritage lines speed is limited to 25MPH but it did strike me as a particular risk.

Agree absolutely!