A different train of thought .

[Chuffer]

As many of you will know , I am a bit of steam locomotive enthusiast with a long history of firing , driving and restoring / repairing them .Some members that have a passing interest or just curious about the mechanical ins and outs of different types of engineering have suggested I start a thread on the locomotive overhauls I am involved with . So to that end , here we go ! The main object of our teams attentions at present is the heavy general overhaul of `King Arthur ` Class locomotive number 30777 ` Sir Lamiel` which is the only surviving example of its class as all the others were cut up for scrap many years ago . They were all named after characters from Arthurian legend and were designed for hauling express passenger trains on the then London & South Western Railway ( LSWR) . The first 10 members of the class were introduced to a design by R.W. Urie who was Chief Mechanical Engineer ( CME) of the LSWR in 1918 . A further 24 , `Sir Lamiel` included were built to a modified design in 1925 by the then CME of the LSWR , R.E.L. Maunsell . They had 3 pairs of 6ft 7 ins diameter driving wheels , a total weight of 138 tons 3 hundredweight and a Tractive Effort of 25,320 lbs / feet and a working boiler pressure of 200psi and powered by 2 outside mounted cylinders of 28 inch stroke x 20.5 inch bore with long travel piston valves . The large 8 wheeled tender carried 5000 gallons of water and 5 tons of coal .
Fortunately when 304777 was withdrawn from service by British Railways in October 1961 it was saved from he cutters torch and earmarked for preservation for the national collection and now belongs to the National Railway Museum (NRM) based in the UK York . The gallent knight has seen much use in the intervening years both on various Heritage Steam Railways and hauling charter trains on the national rail system all over the UK but has now been out of action for 2 years since it`s 10 year boiler insurance certificate expired . As a member of the 5305 Locomotive Association , the group has negotiated a custodianship agreement with the NRM to carry out the major overhaul and return the locomotive to active service on the Great Central heritage railway in Leicestershire and be certified for use once more on the national rail system in time to celebrate its 100th birthday in 2025 . A big ask but attainable provided we have no more Covid lockdowns and no really expensive nasties are found when the boiler goes of for a rebuild .
Here he is in all his glory when last in service . The nitty gritty technical stuff will follow in my next post .

 

[plastic orange]

I think it's great that enthusiasts are keeping Steam alive for future generations. I stayed adjacent to the railway at Balloch in my early childhood and recall the local service run by fairbairn tank engines and in the summer the large mainline express engines taking tourists to sail on Loch Lomond. We used to play (and get chased) on the turntable at times. In 1960 I remember the introduction of the Blue Trains (electrics) being introduced, then quickly withdrawn after a transformer malfunction. Steam was re introduced overnight and lasted for about a year until the problem was sorted. There was a huge variety of steam motive power used in this period, and great to see from our house.
We moved in 1964 to Errol, again in a house adjacent to the railway (Perth to Dundee) and it was great seeing the final days of steam, with A2's A4's V2's, WD's Black 5's etc. I went to secondary school in Perth by Rail in 1966 - diesel multiple units on way to school and usually North British diesel type 22's on the way home. These diesels were very unreliable and I was late home very often, sometimes they were even rescued by Black 5's. One day I even saw Blue Peter wafting through Perth Station light engine.
I'll certainly be looking with interest your progress with Steam.

Cheers,

Pete

 

[Chuffer]

With the boiler now lifted off the frames ( chassis in automotive parlance ) it is easier to see the general construction and interior details . The first photo is of what is call the `back head` with all the control fittings removed and clearly shows the fire hole door . Next is a view looking into the firebox showing the many of steel and copper `stays ` that attach the inner copper firebox to the external steel firebox . What is known as the foundation ring supports the bottom of the inner firebox and crown stays support the top and palm stays hold the firebox tube plate to the boiler barrel . In addition the firebox and outer wrapper plates , back plate and throat plate are stayed together at approx 4 inch pitch and there over a 1,000 of these stays in every boiler . There strength and integrity is essential to the safety of the boiler and preventing leaks as the void between the inner and outer firebox is full of water together with the whole length of the boiler barrel and is the major steam generating area due to its direct proximity to the fire .
The firebox tube plate can be easily seen with all the boiler tubes now removed . The fire bars forming the grate in the firebox along with the brick arch ( more about that later ) have also been removed giving a much more open and empty view than is the case when all are in place .
The next view is from inside the smoke box ( chimney end) showing the smokebox tubeplate . Each small hole represents were at flue tube connects to the firebox tube plate and carries the hot gases from the firebox along the length of the boiler heating the water in the boiler as it is drawn towards the smokebox . There are 167 of these 2 inch diameter tubes . The 24 larger holes carry the 5.25 inch diameter large tubes that have trombone shaped superheater elements inside that convert saturated steam into superheated steam which I will explain more about later . The total superheater element is 337 sq. ft. and the area of the grate in the firebox is 30 sq. ft . In total there is a heated surface area of 162 sq.ft. in the firebox , 1,252 sq.ft. of small tubes area and 464 sq.ft. of large tubes area giving a total heated surface area of 1,878 sq. ft. Basically , the greater the heated surface area , the greater the steam producing capability of the boiler .
The boiler is attached to the frames by bolts and rivets at the front end only and the firebox end just sits on heavy steel plates inside the frames . This allows for expansion as the boiler will `grow` in length by as much as an inch from cold to full working temperature ! With the boiler swinging in the air it is easier to see the smoke mounting end with the firebox protruding low at the far end .

 

[Chuffer]

I think it's great that enthusiasts are keeping Steam alive for future generations. I stayed adjacent to the railway at Balloch in my early childhood and recall the local service run by fairbairn tank engines and in the summer the large mainline express engines taking tourists to sail on Loch Lomond. We used to play (and get chased) on the turntable at times. In 1960 I remember the introduction of the Blue Trains (electrics) being introduced, then quickly withdrawn after a transformer malfunction. Steam was re introduced overnight and lasted for about a year until the problem was sorted. There was a huge variety of steam motive power used in this period, and great to see from our house.
We moved in 1964 to Errol, again in a house adjacent to the railway (Perth to Dundee) and it was great seeing the final days of steam, with A2's A4's V2's, WD's Black 5's etc. I went to secondary school in Perth by Rail in 1966 - diesel multiple units on way to school and usually North British diesel type 22's on the way home. These diesels were very unreliable and I was late home very often, sometimes they were even rescued by Black 5's. One day I even saw Blue Peter wafting through Perth Station light engine.
I'll certainly be looking with interest your progress with Steam.

Cheers,

Pete

Hi Pete ,
What a magic place and era to grow up in ! What amazing locos you saw in action too . As you say , many diesel and electric locos were intitially un reliable due to the rediculous haste by the government of the day to push through the `Modernisation Plan` before new designs were properly developed and apprasised . ( sounds familiar !) .
The Type 22`s were notorious for failures as were the Clayton Type 1`s foisted on Scotland that had a propensity to catch fire !! I don`t many people are aware of how many times steam had to come to the rescue ! I love the good old Black 5`s and was on 45110 double headed with 45127 up to Glasgow and Stranraer from Crewe in May 2000 . Hell of run over Shap . Here we are climbing hard at Greenholme on the outbound journey . Also was on 60009 Union of South Africa from Kidderminster to Carlisle and back via the Settle & Carlisle line . We broke the power output record at the time for a steam loco over Ais Gill Summit !

 

[plastic orange]

Great pictures there. I'm very envious of your steam experiences. I had a great conversation with a friend of my neighbours when at her daughter's wedding some time ago. He was a driver on the 3 hour expresses, driving in the main - Kingfisher, although he preferred the ride on the occasional Coronations that were sometimes used on that route (Buchanan Street Glasgow via Perth and Forfar to Aberdeen). Sadly that route closed in the early 80's, what a waste. Talking about Claytons, 1 of them rescued our stranded class 22 on the way home from Perth one evening - the blind leading the blind lol.

Pete

 

[Chris Sale]

Love the detail - keep going!

Chris Sale

 

[Chuffer]

Hi Pete , I bet your friend had interesting tales to tell from his driver days on the 3 hour expresses . They were the last hoorah of the final few A4`s left in service and their exploits were legendary amonst railway enthusiasts . Kingfisher always had a reputation of being `a good `un ` as was Union of South Africa which being allocated to Ferryhill depot at the time , often worked the tightly timed 3 hour expresses over that very demanding route . I have nothing but respect and admiration for the steam era railwaymen who worked long and unsociable hours in all weathers doing a very physical job . As they used to say , " you never saw a fat fireman " ! There was a decidication to the job and a comradery that just does not exist any more unfortunately . You mentioned the Duchesses that sometimes appeared up there , being born and raised in LMS country in Northampton they are my all time favourite locos and the most powerful steam locos ever built in Britain . My earliest recollections as a wee boy were seeing them in their fabulous maroon livery hammering along the West Coast main line with expresses from London . Under controlled test conditions even two firemen firing in synchronicity could not shovel coal quickly enough to keep up with insatiable demands of the boiler to keep producing steam and hence more power when the loco was being worked hard ! A bit like a Bugatti Veyron running out of fuel before the performance maxed out .
All my boyhood dreams came true when as a fireman , I was on 6233 `Duchess of Sutherland` , the only opertaional preserved example . Even though we were restricted to the 25mph maximum permitted spead on heritage lines , we were hauling 9 coaches with a gross tonnage of about 260 tons and the sense of power was awesome . A few years later and promotion to driver saw me actually driving her too .

 

[Chuffer]

Love the detail - keep going!

Chris Sale

You will regret saying that Chris , they could be another 2 years of it !

 

[Chuffer]

To better explain my initial post on boiler design and construction I have attached a generic boiler diagramme showing the layout of firebox , boiler tubes , superheater elements and their relationship to each other along with the water spaces and the flow of heat around the firebox and into the flue tubes . Heat is drawn by the venturi effect of exhaust steam from the cylinders being discharged up the chimney via the blast pipe . This forms a partial vacuum in the smokebox and draws the heat and smoke through the tubes in the boiler . So the harder a loco is worked , the more powerful the blast up the chimney , drawing more heat more quickly through the boiler and hence producing more steam . Saturated steam is collected via the regulator valve in the dome above water level and is passed through the superheater header in the smokebox into rows of superheater elements where the saturated steam is subjected to more heat to remove excess moisture . The advantage of superheated steam being that any entrained water contained in the saturated steam is converted to additional stem , prevents cylinder condensation and it volume increased by approx 30% over that of saturated steam at a working pressure of 225 psi . In consequence the demand on the boiler to produce steam to the cylinders is considerably reduced resulting in a saving in water and coal .
I will go into more detail about the properties of coal and its efficient combustion in another post .

 

[phild]

What a great thread. I too have a great interest in steam. I live near the Bluebell Line and enjoy the occasional dining experience on board. I'm also a devotee of the Welshpool & Llanfair light railway which was part of my childhood having lived, almost, on its doorstep.

Looking forward to more of this.

 

[plastic orange]

I attended a Class 47 loco on fire at Broughty Ferry Station back in the late 70's and while we were waiting for a spare loco to pull it to the loco sheds at Dundee I got chatting to the driver. Very interesting, he said he was a fireman on the P2 Cock O' The North back in the day, and his head was down for the entire trip Aberdeen to Dundee shovelling coal to keep it fired.

Pete

 

[CaptainK]

Excellent writing thanks Chuffer. I very much enjoy reading it and understanding how steam locos works. Thankyou.

I live near the West Somerset Railway and have been on it a few times, attend the shop at Bishops Lydeard end a lot for my model railway, and before COIVD I was hoping to do all of their driving training courses. But that got cancelled for a while, and I'm unfortunately a bit busy at the mo. Maybe next year or the year after.

Look forward to the next read thanks Chuffer.

 

[Chuffer]

What a great thread. I too have a great interest in steam. I live near the Bluebell Line and enjoy the occasional dining experience on board. I'm also a devotee of the Welshpool & Llanfair light railway which was part of my childhood having lived, almost, on its doorstep.

Looking forward to more of this.

Thanks phild

 

[Chuffer]

I attended a Class 47 loco on fire at Broughty Ferry Station back in the late 70's and while we were waiting for a spare loco to pull it to the loco sheds at Dundee I got chatting to the driver. Very interesting, he said he was a fireman on the P2 Cock O' The North back in the day, and his head was down for the entire trip Aberdeen to Dundee shovelling coal to keep it fired.

Pete

I can well imagine that guy shovelling his heart out on the P2 , what an exprience ! It was really quite an advanced design when built in 1934 . The A1 Locomotive Trust that completed the modern replica of A1 Pacific `Tornado` in 2009 is now building a replica of the P2 . That will sort the men from the boys when it goes out on the national rail system , provided we can still get the coal ! Tornado is a real beast itself with lots of power and very smooth running on roller bearing axles . The cab is a cross between the flightdeck of a 747 and the bridge of the QE2 with so much old and new tech crammed in . It has dual braking systems , one for old fashioned combined steam / vacuum brake sustems and one one for modern air brake train systems . There are controls panels for modern automatated train protection and warning systems , steam generated electricity for running lights , cab lighting , inspection lighting under the loco for oiling up and preparing the loco in the dark and even a mobile phone charging point and 2 way radio for communications with Network Rail Area Control Centres !! I lucky enough to drive it when it was `fresh out the box` . A big moment for me . Here I am waiting toback onto the train at Kidderminster and then on the 1 in 100 climb up Eardington Bank .

 

[Chuffer]

Taking my earlier post and diagramme of how a loco boiler functions at its optimum level , we need to understand a bit more about coal and its combustion . It`s not just a case of chucking it in and setting fire to it ! Reference was made to the removal of Sir Lamiels brick arch and grate and these components together with their relationship to the firehole door and baffle plate are vital for maximum combustion .
Coal consists of approximately 75% Carbon , 10% Ash , 8% Oxygen , 5% Hydrogen , 1.5 % Nitrogen and 0.5 % Sulpher . Coal must be heated to just above 800 deg Farenheit to commence burning but a much higher temp. to burn efficiently . Carbon and Hydrogen each require a definite quantity of oxygen to burn it completely so as to obtain maximum heat value . It is necessary for carbon to combine with sufficient oxygen to form a colourless gas carbon dioxide ( CO2 ) and for hydrogen to combine with oxygen to form water vapour . The sulpher content of coal is small and of little consequence as a heat producer . It is found in coal , especially poor quality coal as a compound of iron known as iron pyrites and can cause the ash to weld together forming clinker . This sets like concrete across the grate preventing air flow for effective combustion and can really play havoc with the steaming rate of the boiler causing a big drop in boiler pressure and is every firemans nightmare ! Breaking it up and digging it out through the small firehole door is bloody hard work and very time consuming . I once spent nearly three hours digging out a badly clinkered firebox with chunks of it the size of paving slabs coming up off the firebars . Not fun !
If oxygen supply is insufficient then incomplete combustion of the gases results in carbon monoxide ( CO) . If only burnt to produce CO then only 30% heat is generated compared to burning to produce CO2 . 1lb weight of coal burnt to CO2 produces 14,550 BTU . If only burnt to CO that 1lb of coal only produces 4,350 BTU resulting in a huge waste of coal . At around 2,500 deg F in the firebox the hydro carbons are split into carbon and hydrogen and are burned to form CO2 and water vapour . If not burnt off this results in black smoke coming off the chimney . That might look impressive to a casual observer as a steam loco powers past but is grosely inefficient . Good quality steam coal contains about 33% by weight of volatile matter and contains practically all the hydrogen present in the fuel . The weight for weight heat value is approx 4 times greater than that of carbon and 1lb weight of hydrogen completely burned to water vapour gives off an amazing 62,100 BTU`s of heat . For those of you not familiar with old fashioned Imperial units of measurement , 1BTU = the heat required to raise 1lb of water 1 deg F . Every loco fireman had to learn all this theory so as to fire the loco efficiently by maximising heat production to produce steam and hence be economical with coal and water consumption .
The purpose if the brick arch referred to is to deflect heat back down from the bed of the fire to burn off all these gases as they are produced before being drawn along the boiler tubes and exhausted up the chimney . What is termed `primary air` is drawn up through the gaps between fire bars in the grate and is hence the primary source of oxygen . The rate of air flow is regulated by dampers at the base of the ash pan operated via a linkage system from the cab .
Secondary air is that which is drawn in through the firehole door and deflected by the baffle plate at a slight angle to pass under the brick arch rather than straight through the boiler tubes and thus having a chilling effect . Utilizing secondary airflow reduces the amount of black smoke given off at the chimney when the driver has shut the off the regulator ( ie : shut power off to the cylinders ) which reduces the draft of primary air drawn through the fire .
Next episode coming soon .

 

[CaptainK]

That was a good read thanks Chuffer. I'm understanding that nicely

 

[Chuffer]

That was a good read thanks Chuffer. I'm understanding that nicely

That`s a relief Cap`n , I thought it might either bore or confound folks . I always said that firing a steam loco is an art form that is rewarding to master and continuously perfect once you understand the science and the physics . Driving is easy by comparison but much more responsibilty !

 

[plastic orange]

I know that back in steam days, certain types of coal were better than others, and performance was dependent on type used. What is the situation now? Also, depending on location, water also has different qualities - soft and hard.

Cheers,

Pete

 

[Chuffer]

I know that back in steam days, certain types of coal were better than others, and performance was dependent on type used. What is the situation now? Also, depending on location, water also has different qualities - soft and hard.

Cheers,

Pete

Decent quality coal , or lack of it has been an issue for quite a while . Russian is used on some heritage railways at present and my experiences of it years ago as a fireman was that it burnt like a wet sack and made so much ash it built up like a snow drift in the firebox ! The Great Central Railway are currently using Scottish and the tender full that they had when I went out on the footplate for trip with the crew a couple of weeks ago looked ok but was very small lumps . That`s easier to shovel but burns away very quickly being small . Back in the early 80`s when I was starting my firemans training on the Severn Valley we could still get good Welsh Steam coal . It was very soft and needed plenty of `cooking ` to get it really hot but that was what the old Great Western Railway thrived on . Then we had Daw Mill coal from near Coventry which was very hard and often came the size of tombstones which had to broken up . Be very hard coal it cracked and spat in the firebox like a fried breakfast but had a high calorific value . The indifferent nature of coal available today often causes problems with clinkering up on main line running steam charter trains these days due to the hundreds of miles covered at high speed with a very hot fire . Not like pottering about for a few miles at 25 mph on a heritage railway .
Water quality is a big issue as you say . Hard water causes lots of scale to build up in the boiler and reduces efficiency and requires more frequent boiler wash -outs . Other chemical issues with water can cause premature boiler failures and we had real problems back in 0`ties on the Severn Valley Railway with so many locos failing in quick succession . This was all down to Severn & Trent Water Authority changing their supply sources . An n automated water treatment plant was installed in the supply to all the water tanks at the loco sheds and yards to ensure an even quality throughout the railway . Previously we used to just tip a jug ofmy experience tannin in the loco tender tanks at fill up time .
Cheers ,
Mike

 

[Chuffer]

Latest Update . The job of cleaning years of thick oil , coal dust , and general build up of grime has commenced to get down to the original painted surfaces . All done by hand with scrapers and copious amounts of brush applied old deisel oil . Loose paint and rust is being removed with scrapers and chipping hammers . The worst affected and more complex areas such as the wheel bearing Horn Block castings will be needle gunned . The idea being to retain as much sound paint as possible so that patch priming can be applied to bare metal areas and the remainder flatted off , undercoated and two top coats later in the rebuild .
Many long and complex lengths of copper lubrication pipework that gravity feeds the axle boxes and the horn block faces have been removed to give clearer access . These piped will be annealed and re -used and brazed repairs to any damaged sections . Photo 1 is the view of the frames from the smokebox end looking towards the cab . Photo 2 is the view from the cab end showing the partly cleaned surfaces inside the frames where the firebox sat and also the trailing driving wheels axle in the forground and the middle driving wheels axle in centre of picture . These still had the lubrication pipework in place at the time and Photo 3 is a close up of the middle driving wheels axle boxes and Photo 4 a general view looking forward .
The axle box has an inverted U shaped white metal bearing face that sits astride the axle journal bearing . Each axle box contains a large felt pad on a spring loaded cradle at the bottom and the box is filled with approximately one gallon of lubricating oil so the jounal effectively runs in a constant bath of oil . The removable bottom cover plate of the axle box is fixed to the leaf string by a large shackle to provide the suspension to each set of wheels as the axle box slides up and down inside the horns which are faced with phosphor bronze . The whole assembly is riveted to the frames .