West Somerset Railway General Discussion

The "standard" arrangement for a 51xx/45xx etc is a single row of superheaters, 6 in number. That is the condition of 4110, 9351 & all the now existing GWR No 2 boilers except for the ones currently associated with 5668 & 4160 which have the BR modified arrangements broadly doubling the amount of superheat (but at the expense of some small firetubes reducing the associated heating area).

The superheater arrangement in 4160 (and 5668) is double that of a standard 51xx provided with the later type of superheater elements used by BR which use the combined regulator and superheater header in one large casting.

As built the 51xx superheaters consisted of 6 tubes for each element but in the 1950's this was simplified to 4 larger tubes. As a result some confusing figures re heating surface arise depending upon which arrangement is being quoted.

Whilst 4160-4179 might have been built with boilers of a particular type, boiler changes were routine in the works as the GW/BR(W) ran a larger stock of boilers than the loco fleet. Boiler repairs were more time consuming than mechanical repairs and it is very unlikely that 4160-4179 retained the improved boilers throughout their lives.

A 61xx boiler is simply a GW std No 2 boiler run at a working pressure of 225 psi rather than the standard 200 psi, an improvement introduced for more rapid acceleration on suburban services in the London division.

 

Great to hear from you Mr Tiffer. I think you have solved the conundrum i.e. it received an uprated boiler during its service life. From memory, the boiler ran at either 215 or 225 psi on the WSR. I think it may have been the latter.

 

High Guys,

First post.

Regarding superheating arrangements on 4160.

The final batch of the 5101 class large prairies (4160 to 4179) were built with a modified standard number 2 boiler with a 2 row BR version of the original "MeLesCo" type super heater with combined regulator, in addition the boiler barrels were of nickel steel designed for a pressure of 225 psi and the boiler design records show that the entire boiler was stressed for this pressure. In BR service the boilers only ever ran at 200 psi. 4160 still retains one of this batch of boilers but it has run at 225 psi during its first period of operation in preservation.

Because of this enhanced superheating 4160 is certainly a more capable locomotive than other large prairies as confirmed by those writing here who have extensive WSR footplate experience, 5 of the 5101 class having worked on the WSR. In addition 4160 is always highest or close to highest for coal economy as confirmed by the Minehead coal consumption records at around 70 lbs/mile (note this figure covers lighting up coal and consumption through all causes including wash out steam tests).

the 61xx class were the only version of the standard large prairie to run at 225psi, being built for the London suburban services. they were also balanced differently to give a smoother ride.

Incidentally 4160 still holds the record for the highest mileage WSR loco at around 136,000 miles if memory serves me right, although 53808 may well pass this before 4160's overhaul is completed.

Hope this helps,

Andy.

 

Welcome to the Nat Pres madhouse Andy!

 

Welcome Mr Aberdare !

Thanks for confirming that 4160 has a two row superheater. Every day is a day at school I suppose. It appears that the truth is a mix of elements taken from a number of theories.

Do you know why there was a run of 20 "hot rod" versions ? How feasible would it be to restore 4110 as an improved version ? Would it require more than new tube plates ? What else could be done to create a "Super Prairie" ?

 

Why the uprated 20 were built I can only speculate on.

To modify 4110 to the same standard as 4160 would involve replacement of:-

• front tube plate - routine.
• firebox tube plate - not required and very expensive, extra 10's of thousands.
• additional 6 flue tubes - extra few thousand.
• additional 6 super heater elements - extra several thousand.
• pattern and casting for combined header/regulator casting - extra several thousand.

On the plus side 2 copper saturated steam pipes would not be required - saving minor.

Even if the consumption of coal and water was reduced by 10% the alteration will cost more than the coal saving over a 10 year period and may not break even over 20 years.

Andy.

 

A 2MT has smaller cylinders. bigger wheels and a larger superheater so, in theory at least, this is to be expected. It was a great pity that the "meeting" between " L150" and 41298 arranged for last summer did not come about because of shipping difficulties. No doubt though as to which type would be easier from the P&D point of view.

PH

 

The Carnot Cycle is the theoretical description of the hypothetical "perfectly efficient" heat engine, so is impossible to build in reality. In one sense the history of all engine-building is a series of attempts to get as close to M. Carnot's theoretical engine as possible.

 

Judging by some comments you might think we were talking Carnot cycle but its more like Fred Carnot's unicycle

 

Just to clarify things my earlier post could have been more specific. The reference to the 4160 limited site news was nothing to do with the discussion on loco efficiency. It is in fact yet another attack on the WSR in general and Robin White in particular with reference to the sale of 4160 shares by the old regime of the WSRA. Given the attitude adopted by the 4160 ltd majority shareholders towards the WSR PLC it seems to me very unlikely that there is any likelihood of it ever returning to the WSR. In fact given the history I wonder if any heritage railway would be willing to host it . So much for the old board's claim that the sale would protect the future of the loco.

 

Andy, thanks. As a semi educated anorak (and a chemical engineer to boot, what are all these mechanical engineering limitations !) perhaps I might be afforded the luxury of speculation.

The standard Swindon No.1 boiler was modified for the first of the Hawksworth Halls (No.6959 ex SN works 3/44). ie a three row superheater. The SH area was 14.5% of the total (SH plus tubes plus firebox) .

When the order for 4160-79 was placed in 1947 it can be postulated that somebody (whether top down from the Hawksworth design team or bottom up from the DO might be interesting to discover. Are there extant drawings with the approval signatures?) decided that a higher degree of superheat in a Swindon No.2 boiler was desirable. Hence the two row superheater (SH area 9.9% of total)

(Without Nationalisation would these have been the start of a new set of Swindon Boilers ?)

It is interesting perhaps to note that Riddles/Cox et al when utilising a Swindon No.2 for the BR 3 2-6-2 tank increased the SH area further (SH area 17.7% of total)

As a non member of the Swindon genuflecting society I suggest that it was not until the work of Cook/Ell in the 1950s that Swindon finally felt comfortable with high degree superheat. The days of Churchward and low SH (the cynics referred to them as steam dryers) at the beginning of the Century were for long an influence.

A thought. When better acceleration was required by the ' timetablers' for the London outer suburban services the 61xx 2-6-2s were designed with higher boiler pressure (225 psi) ie increase the steam outlet temperature by upping the saturation temperature. The 4160-79 improvements probably (I haven't any steam tables to hand) achieved at least the same whilst remaining at 200psi. 4160 during the period it ran on the WSR at 225psi probably represented the apogee of GWR large prairie tank performance, benefiting from both the 61xx and 4160-79 uplifts.

Michael Rowe

 

A warm welcome to Mr Aberdare. I'll leave you and Mr Maunsell907 to have an interesting conversation about the myriad theoretical possibilities which are all over my simple firemans head anyway. Look forward to seeing you both on the railway over the festive season.

 

It would appear that 4160 was indeed a cut about the average GWR large Prairie the Didcot 61XX excepted with its TWO rows of super-heater flue tubes (sorry all have lent out a large amount of my locomotive technical books and data) and thus a lost not only to the WSRA in terms of the WSRA shares but the WSRplc in coal consumption terms.

My hope would be that the new WSRA board pursue the recovery of the WSRA shares in 4160 ltd rather than the loss of value on the transaction.

It would save so many people a lot of expense and trouble.

The mood of the WSRA membership on this matter at the AGM on October was very clear.

I expect an update at the forthcoming? 4160 Ltd AGM will be interesting for the 4160 Ltd shareholders if the news section on the 4160 Ltd web site is anything to go by.

Back to superheating, the Ivatt Class 4 No 43106 that visited the WSR in 2012 had lots of super heater tube (3 or 4 - unsure) and was notable for the effectiveness of these when "hot" A notable saving in coal and water.

Jeff

 

I note the personal nastiness into which the 4160 Directors have descended.

WSRA members should have every confidence, as I do, that the present WSRA Trusttes will take the appropriate steps to deal with the wrongdoing which occurred in the past couple of years. They have my support and know they can call on my help when it is needed.

I look forward to seeing 4160 properly back in the WSR family stable.

That is all I have to say.

Robin White

 

If recovering the shares would mean that the two major shareholders could be out voted I would agree. Otherwise recovering the money would be preferable.

 

Another super-heater question

DO the 61xx's have a 1 row or 2 row super-heater boiler? - I understand they had a 225 psi boiler

Jeff

 

I don't understand why the directors of 4160Ltd don't just keep quiet rather than draw attention to what happened..................

 

Jeff,

61xx locomotives were built with a single row 6 flue super heater.

Andy.

 

Because either they in denial, or they are trying to muddy the water, they i suspected already decided that 4160 won't return and are going too say, " it's Robins fault" blame her, based on their friends losing power, they in effect backed the wrong horse, if they had any sense they would have taken a non confrontational stance , but they clearly saw their place on the losing side.
What WSR operations have to do is to base future requirements for motive power on the likelihood of not having either the 09, or 4160 based on the line.

 

Thanks Andy, trust you are keeping busy.

Sounds like 4160 is indeed a VSP with it 2 x 6 row super heater flues.

Lets hope that in time, subject to 4160 Ltd shareholder approval, it will return to the WSR to carry on the good work and paying for its overhaul.

Jeff Price