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Going Loco

BLOG - A closer look at our collection of historic locomotives

With a collection of locomotives dating from Victorian times to the 1960s, there's plenty to discover.



Award Nomination for Saint

We were delighted to hear a couple of days ago that our “Saint” project has been shortlisted in the Restoration/Conservation Project category of the annual Museums & Heritage Awards coming just as they prepare to re-open following lockdown.

The prestigious nomination recognises the hard work and dedication of volunteers at the Centre who toiled for almost 24-years to raise funds and then physically deliver the £825,000 project to build 2999 ‘Lady of Legend’.

The team are in great company in the national awards: other shortlisted projects in this category come from the Palace of Westminster, Chatham Historic Dockyard, The Box at Plymouth and Aberdeen Art Gallery

Appropriately, then, this week’s blog provides a little more detail on this colossal project . . .

No 2999 “Lady of Legend” is a recreated Saint Class locomotive of the type introduced by the Great Western Railway in 1902.

The innovative, outside cylinder design was the work of George Churchward, the GWR’s newly-appointed Locomotive Superintendent and incorporated features such as long-travel valves which greatly increased efficiency.

The Saint class performed extremely well, and the design formed the basis for the period of standardisation on the GWR that lasted nearly 50 years until the railways were nationalised in 1948. This unprecedented half century of design continuity, built on the foundation of the Saints, is depicted through the unparalleled collection of locomotives assembled by the Great Western Society at Didcot which includes examples of most GWR types from this era.

Until 2019, the most significant exception was the Saint Class itself as the last original examples were withdrawn and scrapped in 1953, long-before the railway preservation movement was established.

This gap was identified early in the Society’s history and the Centre has long held an ambition to create a working Saint to help demonstrate the GWR story to its visitors.

That ambition came to fruition in 2019 with the completion of a project, 45 years in the making, to build locomotive 2999 using parts from 4942 “Maindy Hall” (one of the classes developed from the Saint design).

Lady of Legend entered service in April at a special ceremony performed by celebrity chef Pru Leith.

The widely held passion for the elegant and efficient 'Saints' meant that many dreamt of creating a new member of the class to showcase Churchward’s pioneering design.

For decades, it was considered to be beyond the capability of preservationists and prohibitively expensive. However, restoration of No. 6023 “King Edward II”, which among other things involved construction of a new driving wheel set, proved that the Society could successfully undertake major reconstruction and refurbishment projects, and the Saint Project was born. 

The scheme centred on rebuilding No 4942 “Maindy Hall” from scrapyard condition and reverse engineering the locomotive to create a Saint. This mirrored the process the GWR had used in 1925 when the prototype Hall Class was produced by the conversion of “Saint Martin”.

No. 4942 had been purchased in the early 1970s with the specific purpose to recreate a Saint but early attempts floundered and the prospect of success remained a dream until 1995 when the project started in earnest.

Major new components that have been manufactured include three new driving wheel sets, as the Halls had 6ft drivers while the high stepping Saints sported driving wheels of 6ft 8½in diameter.  Two bogie wheel sets were cast to the correct 3ft 2in size and two identical 'half' cylinder blocks were cast to recreate the inside cylinders fed by a straight steam pipe that was integral to the Saint design. The lever reverse was also made from scratch while the frames from No. 4942 were extensively modified and strengthened.

Many other components, including the boiler, were refurbished, while still more came from surviving parts from other GWR locomotives – further testament to the far-sighted Swindon practice of standardisation.  Parts include a connecting rod from 2906 “Lady of Lynn” and the whistle from 2910 “Lady of Shalott” and the chimney from a 68XX Class.

The new machine has been numbered 2999, taking the next number in the sequence allocated to the Saints – the previous one, 2998 “Ernest Cunard”, having been outshopped in 1913!  The winning entry in the competition to name the locomotive was “Lady of Legend” as it evokes the GWR practice of naming early members of the class after mythological or historical ladies.

The recreated Saint has been built with straight frames so that it can also run as an Atlantic 4-4-2, as Churchward did in the 1900s. Rear extension frames have been constructed, trial fitted and placed into store.

The £825,000 project, funded entirely by donations and bequests, means that over a century since the previous member of the class was built, an example of Churchward's iconic 20th Century design, which influenced almost all subsequent British steam development, is back on the rails to delight, inform and entertain 21st Century visitors.

The engineering excellence that went to create 2999 was recognised by the Heritage Railway Association in February when the project won the first-ever Chairman’s special prize at the organisation’s annual awards.

We believe the foresight, tenacity, craftmanship and above all determination of the GWS and the volunteer team make this project worthy of an award – we’ll be biting our nails until the winners are announced on 22 September!

2999 will take pride of place in front of the Centre’s iconic Engine Shed as visitors return to the site for a series of Open-Air Discovery Days this month. Visitor numbers are strictly limited and tickets must be booked in advance.  


Social distancing will be vital as the Centre re-opens!



As prepartions continue for re-opening on 4 July, this week's images area again of engines that will be on public view this summer.

Is Everyone Still All Whyte?

Let’s finish off our look at the Whyte System. As a reminder, the first number is the carrying, unpowered wheels at the front, the next number is the powered, coupled wheels in the middle and the last number is the carrying, unpowered wheels at the back. The notations sometimes have names and last time we looked at such things as Branchliners, Bourbonnais and Olomanas. These notations can be quite small. For example, Stephenson’s Rocket can be described as an 0-2-2. No carrying wheels at the front, 2 driving wheels and then 2 carrying wheels at the back. They can get quite long too. The LNER built a single example of the U1 class which was of the Garrett type. This revelled in the wheel arrangement of 2-8-0 + 0-8-2. The Garrett type being an engine that has a single large boiler mounted on what amounts to two separate locomotive chassis with their own wheels, cylinders and motion.

For extra fun, there have been engines with wheel arrangements as bizarre as 2-8-8-8-4 (three sets of coupled wheels - the only one being the Virginian Railroad XA Class No. 700 of 1916). Any engine with 3 sets of driving wheels can be known as a Triplex. There are also the amazing Johnston 16 wheeler geared locomotives from New Zealand logging railways. These can be regarded as either 2-2-2-2-2-2-2-2s or 2-2+2-2+2-2+2-2s. With that, back to the GWS collection.

2-6-2 (Nos. 5572, 4144, 6106): All of Didcot’s 2-6-2s are actually 2-6-2Ts (side tank type engines). This is fairly typical of the wheel arrangement in Europe but those in America were usually tender locomotives (pulling a separate vehicle to hold the coal and water). The first American tender 2-6-2s were built in 1900 by the Brooks Locomotive Works for the wonderfully named Chicago, Burlington and Quincey Railroad. These engines were mostly used on services in the Great Midwestern Prairies which lead to the name Prairie for this wheel arrangement. This is one of the American names in common use in the UK.

2-6-0 (No. 5322): This is another of the wheel arrangement names that sees common use in the U.K. The Mogul name used is of uncertain origin. Some people will tell you that it comes from an engine called Mogul that was built for the Central Railroad of New Jersey by the Taunton Locomotive Manufacturing Company in 1886. There is however a counter claim from the UK for a Great Eastern Railway locomotive also called Mogul built by Neilson & Co of 1879. Whatever the truth of where the name originated, the first tank engine 2-6-0 was built in about 1870 for the Garstang and Knott-End Railway. Now that IS a name!

4-4-2 (technically No. 2999): No. 2999 Lady of Legend has been constructed in such a way as to be able to be converted into a 4-4-2 Type. This is because the GWR did the same with some of the originals as part of a testing program in the early 20th Century. The type was first employed over the 4-4-0 types to enable the fitting of larger, wider fireboxes although this wasn’t the case with the Saints. This type is most commonly known as an Atlantic after the Atlantic City Line 4-4-2 locomotives of the Philadelphia and Reading Railroad. They are also known as Milwaukees after the fast 4-4-2 machines used on the Milwaukee Railroad.

4-6-0 (Nos. 2999, 4079, 5051, 5900, 6023, 6998, 7808): This is one of the GWR’s favourites! There were Saints, Halls, Granges, Manors, Modified Halls, Counties, Stars, Castles and Kings and they were all 4-6-0s. Other railways also had a go at a few apparently... Although the name isn’t used in the U.K., the Americans use the name Ten Wheeler to describe the 4-6-0. This is because there are ten wheels. Did I have to point that out? Probably not...

2-8-0 (Nos. 3822, 4709, 5227): The 2-8-0 is usually for freight. Nos. 3822 and 4709 are both tender locomotives but the No. 5227 is a 2-8-0T or tank engine. The GWR 28XX Class that No. 3822 is a development of was the first UK version of a 2-8-0 and set the standard for heavy freight locos in the U.K. until the end of steam (The B.R. Class 9F 2-10-0 being the main exception). The American name for this type is the Consolidation. The name coming from the 2-8-0 Lehigh & Mahanoy Railroad’s machine of 1866 which was called Consolidation. This was the first 2-8-0 to have a separate pony truck for the front two wheels rather than the leading unpowered wheels mounted rigidly to the frames.

2-8-2 (No. 7202): The 2-8-2 design was relatively uncommon in the U.K. A 2-8-2T or tank engine like No. 7202 was even rarer. They were however, quite common elsewhere in the world. The 72XX Class came about rather by luck than judgement but proved very successful. The first locomotive to have a 2-8-2 wheel arrangement was built in 1884 and called Calumet but this name didn’t stick. The name that eventually came to describe 2-8-2 locomotives- Mikado - was coined after the Class 9700 locos built for the Nippon Railway of Japan by the Baldwin Locomotive Works in 1897. The name comes from the popular Gilbert and Sullivan opera of the same name that was first performed in 1885. During the Second World War, the anti Japanese feeling in America lead to the wheel arrangement being renamed MacArthur after the famous General (despite the fact that the opera was British) but the old name returned post war and is still in use today.

Which leaves us with Railmotor No.93. Well, it’s either an 0-4-0 if you just include the power bogie as a separate locomotive or an 0-4-4 if you include the coach. Or possibly an 0-4-0+4. Is the coach a tender? It does carry the coal and water for the engine after all. Does the fact that the coach wheels does not carry the weight of the locomotive mean that we ignore them? If you include the coach then should it have the WT suffix? The tank is under the floor of the coach after all. The ‘locomotive’ is an integral part of the coach too. We will leave that one to you...



As we prepare to re-open on 4 July, this week we unlock the mysteries of describing the wheel arrangement of locomotives and illustrate it with engines that will be on public view this summer.


Is Everyone All Whyte?

Quite often the loco department, like anything that has been around for a while uses jargon and acronyms. Anyone who has ever watched or read anything regarding space will know what we mean. There was once a proposed device that revelled in the name OWL Telescope (OverWhelmingly Large) which was sadly scrapped in favour of the smaller ELT (Extremely Large Telescope) design. We are not making this up! Engineers are really good at adding in this sort of buzz word stuff and the most common for us at Didcot has to be the Whyte Notation System.

Frederick Methven Whyte (they don’t make names like they used to do they?) was a Dutch / American engineer born in 1865. His idea came into common use following a December 1900 editorial in American Engineer and Railroad Journal. While describing an engine as a 4-6-2 might sound complicated to the uninitiated, it really isn’t. A 4-6-2 locomotive would have 4 unpowered weight carrying wheels at the front of the engine. It would then have 6 powered or coupled or driving wheels in the middle, followed up by two more unpowered weight carrying wheels at the back. What is important to realise is that you only include wheels on the locomotive, not on the tender (the vehicle out the back with the coal and water in) if it has one. This is treated by the Whyte System as a separate vehicle and is ignored. There are lists of suffixes that get added to denote various things, some of which we will look at. There is also a whole host of names that get used to describe the wheel arrangements (a 4-6-2 is known as a Pacific), not all of these are in common in use in all parts of the world. It’s mainly an American thing but some of these names have leaked into British usage. Let’s have a look at Didcot’s collection.

2-2-2 (Firefly): The first 2-2-2 was an expanded version of Stephenson’s earlier 0-2-2 and 2-2-0 designs. The idea being that it gave you the chance to fit a larger firebox. Any loco with just one driven axle can be known as a single but the 2-2-2 design was also named the Patentee after the engine built by Stephenson in 1834 and later it was called a Jenny Lind Jenny Lind was a popular opera singer who got a 2-2-2 engine named after her in 1847. She was also known as the ‘Swedish Nightingale’ which we think should be a name for an engine if it isn’t already.

4-2-2 (Iron Duke): Another Single. Also known as, wait for it, the Iron Duke Type because of the GWR Iron Duke Class locomotives. Like our Iron Duke. Sometimes this wheel arrangement is known as a Bicycle too. You have to love that...

0-4-0 (Nos. 1, 5, 1338, 1340): When there are just driving wheels under an engine, the wheel arrangement is sometimes just referred to as a [something] coupled type, so an 0-4-0 is a 4 Coupled but this is not exclusively recognised. Sometimes locomotives with different wheel arrangements with the same number of coupled wheels are also known as 4, 6, 8, 10, 12 or (one Soviet example - it couldn’t go round corners!) 14 coupled. It’s a phrase that is used lots of different ways. The first ever steam railway locomotives - Richard Trevithick’s machines of the very early 19th Century - were 0-4-0s. This is where we start to get into the suffixes. No. 5 Shannon is an 0-4-0WT. Tank engines carry their supply of coal and water on the locomotive chassis and do not use a separate tender. Where they carry their water is what makes the difference. WT stands for Well Tank and Shannon’s water tank is between her frames, below her boiler. Arguably a well of water! Nos. 1 Bonnie Prince Charlie, 1338 and 1340 Trojan are all 0-4-0ST engines. ST standing for Saddle Tank and one look at the large round saddle-shaped water tank atop their boilers will tell you why...

0-4-2 (No. 1466): No. 1466 is an 0-4-2T. The T suffix means any locomotive that has water tanks that don’t hang off the boiler, but are mounted either side of it. These can be in a variety of shapes and may have an additional water tank under the coal bunker at the back. They are sometimes called side tanks but to avoid confusion with saddle tanks, they just get a ‘T’. The exotic name sometimes used for an 0-4-2 is an Olomana. This name refers to a little narrow gauge engine built in 1883 in America by the Baldwin Locomotive Works of the same name. It was shipped out to Hawaii and was only the third self-propelled machine to operate on the island. Its working Life was spent at the Waimanalo Sugar Company and it is preserved as part of the Smithsonian Collection, being owned and operated at one point by Walt Disney animator Ward Kimble. Walt Disney himself was a frequent driver of the machine!

0-6-0 (Nos. 1363, 2409, 3650, 3738): As with the 0-4-0, the 0-6-0 gets referred to as a 6 Coupled sometimes. The French have also been known to call them Bourbonnais which was an early locomotive to operate in their country and is named after the region of France. With Nos. 3650 and 3738, we get the last of Didcot’s different suffixes here with the most famous being 0-6-0PT. This means Pannier Tank, the 2 water tanks hanging off the sides of the boiler which in smaller locomotives, offers better access to the Woking parts between the frames although there are additional reasons why the GWR adopted it too (see our blog post entitled The Big 13 - Lucky For Some). Nos 1363 and 2409 are both 0-6-0ST or saddle tanks.

0-6-0 Diesels: Vehicles like Railcar No.22 and Gas Turbine Prototype No. 18000 aren’t usually described using the Whyte system as they run on separate powered bogies driven by means other than steam. The Whyte System does apply to some of our other diesel locomotives. Typically, small shunting locomotives that look more than a little like their equivalent steam locomotives. The D stands for Diesel (the type of energy consumed by the drive motor) and the next letter denotes the type of transmission. Therefore:

Class 08 No. 08604 Phantom is an 0-6-0DE (Diesel Electric)

No. DL 26 ‘The Rat’ is an 0-6-0DM (Diesel Mechanical)

Class 14 No. D9516 is an 0-6-0DH (Diesel Hydraulic)

0-6-2 (No. 6697): This is a typically Welsh design - well suited to storming up and down the valley lines they inhabited. There are 2 names associated with them. Branchliner refers to a series of American locomotives that were originally 2-6-0 tender types that had larger fireboxes fitted, necessitating the carrying wheels being moved from the front to the back. They were mainly used for branch line work, hence the name. The other name used, Webb, is in reference to the British locomotive designer Francis William Webb and his famous ‘Coal Tank’ class of 0-6-2s.

We will leave the rest of the Collection for another time as this is getting quite long enough now, so this is the first of an epic 2 - part blog! A passing thought to end on. How do we classify our Wickham Trolley No. B42W? It has a petrol powered engine, driving a mechanical transmission so the suffix is PM. Sometimes small diesel locomotives just have their number of wheels quoted so it might be that No. B42W is a 4w PM. But, you could also describe it as a 2-2-0PM as only the rear two wheels are driven. Is it a locomotive? It can pull small trailers so it can form a train. We will leave you all to figure that one out.

Part two next week...



1363 - Survivor Extraordinaire!

We chatted a little while back about the historic significance of the ‘Big Thirteen’ (see Going Loco Archive) but what is equally fascinating is how this engine became preserved in the first place and it involves lots of people over whom No. 1363 seemed to have cast her own spell. When she was withdrawn, she had only done 18,000 miles since her last overhaul. Her last official shed was Plymouth Laira and the staff there were enamoured somewhat with this little tank engine. She had had a dent in her bunker where she had had a ‘disagreement’ with a Hall Class locomotive a few years back but to them it must have just added character! At the time there were just two surviving GWR Swindon-built saddle tank locos. No. 1363 and her sister, No. 1365 which had been shedded in Bristol but unfortunately did not have long left. This fact had not gone unnoticed. No. 1363 had been stored out of use for quite a while. She was previously used as regular loco for the Plymouth Millbay Harbour area but now sat cold with an uncertain future.

The BR staff at Laira were ordered to clear the depot of any remaining steam locos by sending them for scrapping. These were mainly ‘County’ class engines (getting one of those too would have made our current job a bit easier!), which were formed into a long line with 1363 at the head. It looked like the end. One last trip... The staff of the shed, including the shed manager, had been making every effort to keep No. 1363 under their care. She was even being maintained by them in their spare time. They were desperately looking round for a bolt hole for her and they weren’t going to let her go that easily. Unbeknown to the crew that came to take her away, the shed staff had been busy the night before. At the suggestion of a man in the know, a few key items had been removed. These were a good few of the bolts that held the front buffer beam and coupling in place. No. 1363 was the last loco placed in the train. The diesel coupled up and went to pull away. The weight of the train of dead engines and the effort of the diesel did its terrible work. There was a sickening noise of tortured metal. The front buffer beam had been torn outwards and the coupling was so badly damaged that it was impossible to tow the engine. You can imagine the conversations. Oh dear, there, there, never mind. That looks unfit to travel... Once the train had gone, No. 1363 was quickly squirrelled away in a corner of the roundhouse. Where she stayed. For about a year!

While all this skulduggery was going on, 4 schoolboys had started a group to buy a 14XX Class locomotive and its accompanying auto trailer coach. This was of course the start of the Great Western Society. At the Society AGM of 1963, it was suggested that perhaps the society (who had not yet bought No. 1466 and coach No. 231) would be better served to lower its sights and try to get a smaller, cheaper locomotive first. The suggestion was made that No. 1363 - due to its unique history - would be a much better bet. Ultimately, as we know, that idea was turned down but it had planted the seed of an idea in the mind of the then Chairman Peter Lemar. He saw the need to preserve the locomotive and along with his brother-in-law, Alan Edwards (a senior MOD engineer) arranged to inspect the locomotive. Despite having to remove the ash from the last fire, the inspection showed that the locomotive was in generally excellent condition and with a little light metalwork (to the front buffer beam!), would make for a very sound prospect for preservation. 


Peter and his wife Joan set up a separate fund to buy the locomotive and were able to raise the money in a fairly short amount of time.  They actually ended up with offers of money that totalled almost twice the asking price of the locomotive. Therefore the locomotive was purchased and became a preserved engine. The purchase had been done privately so Peter was technically the legal owner. There were a few people that had been involved in the purchase so Peter and Joan gave them a number of choices as to how to proceed with her preservation, including the backers keeping the engine themselves. The overwhelming result of this ballot was to donate No. 1363 to become part of the Great Western Society collection and as such she became just the second item of rolling stock owned by the Society, shortly after No. 1466 had be purchased.

When you hear how close to destruction this engine was on several occasions, you realise just how lucky we are to have her. You also realise what a lottery preservation is and that it was often a confluence of unlikely events that resulted in a piece of rolling stock being saved. We have a lot to thank the early pioneers of steam preservation like Peter and Joan Lemar and those guys all those years ago at Laira who were so determined to save their shed pet! Peter was instrumental in preserving a number of the vehicles in the collection and purchased some of them himself. It is really a tribute to people like him and all the other GWS trailblazers that the collection at Didcot is so wonderfully diverse and interesting. Although Peter passed away a few years ago, when we steam No. 1363 again after her overhaul, we will no doubt pause to remember him and all the others that did so much to ensure that this fascinating little engine was passed down to future generations.

You can donate to our Small Locomotive Fund which support the restoration under maintenance of 1363 and other small tank engines at Didcot.



Under Pressure

The steam locomotive boiler is a wonderful bit of kit. It uses all sorts of clever science to make steam so we thought we would take a deep dive into the way one of these things works. Mind your head on the way in...

The first thing to say is that it is, like any machine, a device to convert one type of energy into another. In this case we start with the chemical energy bound up within the coal itself and convert it to heat energy. The chemical energy was laid down eons ago (the story of coal is for geologists to explain far better than us steam loco engineers!) and is released when a flame is applied to the coal. To put it another way, we burn it! In order for the coal to burn more efficiently, it needs to have sufficient access to air and there are two directions it can come from. Underneath through the grate or through the fire hole door, where the fireman puts the coal in. Adjusting the damper doors on the ash pan and the fire hole doors in the cab gives the fireman a pretty accurate control of the airflow into the fire. With a bit of experience course.

All this takes place in a big metal box. With a fire in it. It’s called a firebox. We locomotive types are not complicated people... there are two walls here. The inner one is made of copper on all of our GWR locomotives. Then there is a space where the water goes and this is heated by the energy coming through the copper walls. Then there is an outer firebox made of steel. On the front of this is a big barrel shaped protuberance called the barrel (again, not people likely to win literary prizes). Inside here are a number of tubes. The vast majority of these are fire tubes - the hot gasses from the fire travel along their length. The water is on the outside of these and is heated by the thermal energy flowing through them.

The multi-tubular boiler is one of the greatest innovations of the steam age. Really early steam engines just had one, large diameter tube for the hot gasses from the fire to pass through. Not long after this, it was realised that if you put a number of tubes of smaller diameter in the boiler instead of one big one, you increase the amount of hot surface area that the water can come in contact with. This makes it more efficient - you get more useful energy out of the coal you are burning. It was present on Stephenson’s Rocket in 1829, on the original GWR Firefly Class in 1840 and it was present when Swindon built 9F Class 2-10-0 No. 92220 Evening Star in 1960 as the last ever British main line steam locomotive. A good idea is a good idea.

There are a few really clever bits about the way a locomotive boiler works.

Clever bit No. 1: The harder you go chuff, the more air goes through the fire! That’s right - the steam comes out of the boiler, through the regulator (the steam engine equivalent of the accelerator in a car) and is used in the pistons. It is then exhausted up the chimney via a conical shaped device called a blast pipe which accelerates the steam as it goes through it. Remember the Venturi effect? This causes the air pressure in the smokebox (the black bit with the door on it at the front of the boiler, where the smoke goes through, we do like the simple names remember...) to be lowered. This causes the hot gasses to be pulled through the tubes in the boiler to heat the water that surrounds them. In doing this, it lowers the air pressure in the firebox, drawing fresh air into the fire making it burn hotter! The harder the engine is working, the more steam it needs and the more steam it produces. Well, that’s convenient!

Clever bit No. 2: The firebox really should melt. The copper that all the GWR fireboxes are made of might be a special, slightly more heat resistant type (arsenical copper for those that have to know) but it melts at 685 degrees C. (1265 degrees f.). The fire however burns a lot hotter than that and indeed the copper goes soft and would therefore result in a catastrophic failure (a.k.a. an explosion!) long before that temperature is reached. Pressure likes to get out and when you are dealing with up to 250psi (King Class), it REALLY does it’s very best to escape. So, why not? Because physics! We have established that copper does not have the ability to withstand a large amount of heat energy inside itself. It IS however very good at moving that heat energy from one place to another. It is a fantastic thermal conductor. The water on the outside of the copper part of the firebox has an enormous appetite for heat energy. Ever wondered why heating a bath full of water or the water in your radiators takes so much energy? Water can absorb a very large amount of heat energy. So, the copper takes the heat energy from the fire and conducts it through itself to the water on the other side and the water absorbs that heat energy, keeping it cool and preventing it melting. Simple!

Clever bit No. 3: The superheater. This is one of these ‘two bites of the same cherry’ type deals. If you have a big loco that is required to make a great deal of steam for a prolonged period of time (say, Paddington to Bristol), every ounce of energy you can get to go to turning the wheels then the more efficient the locomotive will be. So, the steam in these bigger engines is released through the regulator valve and instead of going straight to the cylinders it goes instead back into those hot gasses coming from the fire. Here is where things get weird. We have to talk about wet and dry steam. It’s all made of water - how can that be I hear you cry?! Ok - wet or saturated steam is the stuff that comes straight out of the boiler. Dry steam is also known as superheated steam and the big difference is the amount of energy bound up within it. The steam travels from the regulator, through the superheater header, into a series of smaller tubes known as elements. These are inside larger fire tubes called flue tubes. This gets the steam the second bite at the energy coming off the fire. The steam

Then goes off to the cylinders where the extra energy reduces the likelihood that it will condense in the cylinders, raising the efficiency of the engine. Think of it like a steam engine version of a turbocharger.*

There are lots more really clever bits of engineering on a steam locomotive and its boiler but rather than write something that is 30,000 words long, we will save some more for another day. To be continued.

*For some unknown reason, the little covers on the side of the smokeboxes of some GWR engines seem to have collected the name ‘superheater covers’. Quite where this idea came from is unknown, but the covers are there just to tidy up the look of some oil pipes. The superheater system itself is WAY too big to fit under them and is completely contained inside the boiler and smokebox anyhow. It does not need covering.




We’re NOT going on a summer holiday...

(With sincerest apologies to Cliff Richard)

As it’s English Tourism Week, and there can’t be too much of the real thing going on right now, we thought that we would take you on a virtual journey with the aid of our GWR locomotive collection. Of course, Brunel’s original intention was to have the trains meet the steamships at Bristol and that GWR took you to New York but we digress. Let’s see how far we can get from Didcot. The rule is that it has to be a GWR loco that is definitely named after a place (not a historical or mythical figure) that actually exists. Join us if you will...

There is a whole plethora of suggestions of places to visit and indeed many of the locomotives were named after tourist attractions that the GWR could help you reach. Canny folk these old school GWR types - subliminal messaging on the engines... As classes got bigger and bigger, the net got cast wider and wider as examples on the GWR network dried up. This is particularly apparent in the Halls and Castles. Let’s have a look at the engines in our collection named after places and see if we can get provide some inspiration for you when normal travel and tourism resumes - after you have visited Didcot Railway Centre of course!

Cookham Manor (No. 7808) isn’t an easy one to tie down as a destination as there really isn’t a specific building called Cookham Manor today. There are a few buildings that could well have acted as the local manor house but as these are all private dwellings or businesses, we had better not direct you tourists there... So, breaking the rules slightly, having a look in the excellent Stanley Spencer Museum and then a bite to eat and a drink in one of the many pubs and restaurants in the little high street there is your best bet frankly! It’s only about 30 miles from Didcot as the crow flies and it’s rail connected too by the former and indeed our friends in the modern GWR.


Hinderton Hall (No. 5900) is just outside Neaston in Cheshire. It is notable in that it was designed in 1856 by noted architect Alfred Waterhouse who you may know from his work on the Natural History Museum in London and Manchester Town Hall. It has been used as offices in the past and is now open for events and functions. This gets us out to 186 miles from the centre.


Burton Agnes Hall’s (No. 6998) namesake is in Yorkshire. It was built for Sir Henry Griffith between 1601 to 1610 and it stands adjacent to the still surviving Norman Manor House from 1173. In immaculate condition, it is normally open for visitors and events venue and is 212 miles from our little corner of Oxfordshire.


Drysllwyn Castle (a.k.a. Earl Bathurst, No. 5051) is sited on a small rocky hill between Carmarthen and Llandeilo. This is English Tourism week so we can’t go into depth here. Sneaky website address below however - quite interesting, shhhhh! That gets us 165 miles from home shed.


Also in Wales, The County of Glamorgan (No. 1014) has a lot of great attractions in it and although our initial inspiration was English Tourism Week, we have included a link to their tourist website below. To give us our measurement, Barry Island where the former site of the famous Scrapyards is would be about a 122 mile journey from Didcot.

The frames of our County replica return us to England as they come from Willington Hall (No. 7927). The building is in Cheshire and is a grade II listed structure built in the Neo-Elizabethan style in 1829. Its slightly smaller that it was as originally built and is used today as a hotel which requires any of us at Didcot to have to travel 158 miles if we want to stay there.


Pendennis Castle (No. 4079) is an artillery fort built on the orders of King Henry VIII (No. 6013 - not preserved but we just couldn’t resist it!) between 1540 and 1542. It is situated just outside Falmouth in Cornwall and was under siege in the English Civil war by the parliamentary forces who were led by Oliver Cromwell (No. 70013 - in the NRM collection. We promise to stop now...). It is a English Heritage property and a trip there from 81E will be one of 255 miles, giving us our local distance champion!


Just for fun, let’s look a beyond our collection and open the history books. The Star Classes. There have been two. The first set of engines were broad gauge, built near to the middle of the 19th Century. The second were standard gauge, built in the early 20th Century. They followed basically the same set of names. Sadly, not all of the Star Class names refer to specific celestial bodies (eg: Red Star or Rising Star) but for certain we can definitely tie down these few to specific heavenly objects.

The perennial favourite Evening Star (built in 1839 or 1907 or by BR as a Class 9F 2-10-0* in 1960) is an alternative name for the planet Venus and is about 25,000,000 miles away. Morning Star (1839 or 1907) is possibly confusingly also named after Venus. You can then have Dog Star (1839 or 1907) which refers to Sirius which is in the constellation Canis Major - hence the name. Actually, it’s a binary star made of the larger Sirius A and the smaller white Dwarf Sirius B. One of the closest of our stellar neighbours, it’s at a distance of 8.6 light years or 50,560,000,000,000 miles away. Which would have taken our weekend getaway destination crown, if it were not for our winner.


Which smashes it out of the park. . .

North Star (1837 or 1906), Polar Star (1840 or 1907) and Lode Star** (1841 or 1907*) all refer, in one way or another to Polaris. The Pole Star, beloved of navigators here on Earth due to its brightness and position approximately above the North Pole. It is, wait for it, about 433 light years away. That is a staggering 2,545,000,000,000,000 miles away from Didcot.

This post was done with the most cursory of glances, so for a bit of lock down fun, but it’s now your turn. How much further from Didcot than our loco names could you travel on a GWR name plate? There are four categories:

English destinations

Other U.K. place names

International travel


The loco need not be preserved. It has to be definitely named after a real place and may not be something that was probably named after something else - for example the broad gauge engine Mars or Jupiter were named after the Roman gods and not the planets. Please post your answers on our Facebook page. Over to you...


*Both No. 4003 Lode Star and No. 92220 Evening Star are part of the National Collection along with No. 70013 Oliver Cromwell. Please consult their website to find out where they are currently located.

** The word lodestar (it can be spelt without the space as well) can also be a used to describe any star that can be used as a navigational reference point but its etymological origin is as an archaic name for Polaris. This is from the archaic word lode which means way, path or road. Which brings this footnote full-circle...



A valve by any other name could be a gear?

Let’s dive under the skin of our locos for today’s blog post! There are lots of valves on a steam locomotive. Arguably, the most important are the two on top of the boiler - the safety valves. These allow an excess of steam pressure to be released if it goes too high. Without these, things could go very wrong - quickly... We will save boiler talk for another day, however. There are valves that control the whistles. It was not unknown for, on rare occasions, these valves to get stuck open. Imagine the noise! There isn’t any easy way to stop it while the engine is in steam either. Today, let’s look at the valves that make the engines go: the ones next to the cylinders.

These valves do a two-fold job. They allow the fresh or live steam from the boiler into the side of the piston so it can push on it. It also opens the exhaust port to allow the steam that has been used on the other side of the piston to escape up the chimney and make that lovely noise we all like to hear(!). These valves are moved backwards and forwards by the valve gear - a complex subject in its own right. Through the valve gear, we can make changes to the way the valves operate. In the same way a car has gears, a steam engine has a similar sort of setting called cut off. This is controlled by the reverser. The reverser can be either the pole type - a long lever with just a few settings on it but quick to use or a screw type which has a huge range of different settings, adjusted by winding a handle. This takes more time and effort to operate, however. Later passenger and mixed traffic engines as a rule had screw reversers. Engines that primarily did slower goods work or shunting that needed to change direction frequently have pole reversers. As she is based on an earlier passenger loco, No. 2999 “Lady of Legend”, bucks this trend and has a pole reverser! (Iron) horses for courses...

Just like a car, you pull away in the equivalent of 1st gear which is, on a steam engine, is usually marked off on the reverser at 75%. This means that for 75% of the total distance that the piston travels from one end of the cylinder to the other, live steam is being allowed to push on it. So, Lady of Legend has a piston stroke of 30” (762mm). At 75% cut off, when the piston starts its journey down the cylinder, live steam will be injected until the piston gets to a point 22.5” (571.5mm) or 75% along its travel to the other end. The final 25% of the journey is to allow the steam to do its work and expand.

Now you don’t drive your car around in first gear (we hope...) and likewise, you don’t do the same with a steam engine. If you left the engine in 75% cut off, you will empty the boiler of steam very quickly and end up with a very grumpy fireman. So, what you do is to go ‘up the gears’ by reducing the cut off. So, as you accelerate your express train out of Paddington, you go through 50% to a cruising speed of, perhaps, around 70 to 80 miles an hour at roughly 25% cut off. At these low cut offs, the idea is that the locomotive has overcome the weight of the train and is now just keeping it rolling. This requires less energy. So, the valve is now only allowing steam in for just 7.5” (190.5mm) or 25% of the pistons travel. The amount of steam going in is less and the steam is being allowed to expand much further. This is much more efficient.

If the engine starts to work harder going up a hill for example, the driver will increase the cut off and the fireman will have to work that bit harder to keep up. He should of course get a bit of relief on the other side of the hill as when it rolls down with the help of gravity. Thank you Sir Issac Newton...

Don’t forget that steam loco pistons are double acting. Unlike in a car engine, a steam locomotive piston is driven in both directions. Forwards and backwards. That’s two changes of direction in one revolution of the wheel per piston. That’s four very precise changes of valve position and therefore piston direction for every revolution of the driving wheels for a two-cylinder engine like No. 2999. With four Cylinders machines like our King or Castles, you need eight very accurate changes per revolution. Now consider how many revolutions per second are being done by the wheels of that King or Castle if it was going all out at 100mph...

This photograph shows No 7018 soon after she was the first of the Castle class to be fitted with double chimney in May 1956. She is hauling the Torbay Express from London to Kingswear, and under test with cables leading from the smokebox to the dynamometer car which is the leading vehicle in the train.



Taking The Water

Amongst the varied collection at the Railway Centre, we have a rather unusual piece of steel channel which is currently tucked out of the way in the corner close to our Science of Railways carriages

The item in question is a short section of water trough. These were located at strategic points on the Great Western Railway to allow steam locomotives to pick up water on the move and thereby eliminating the need to stop to fill up.

The nearest set of troughs to Didcot were situated at Pangbourne, about 12 miles away as the crow flies and around 17 minutes by stopping train. All four lines were equipped with the troughs, which were fed by water from a small treatment plant situated next to the railway.

To pick up water the fireman would lower a scoop underneath the locomotive’s tender scoop once the tender was over the trough, and raise it when the water indicator showed the tank approaching full and definitely before the end of the trough. If the fireman was slow in retracting the scoop, the tender would overflow from the rear filler and deluge the leading coach of the train!

The following is an abbreviated extract from the GWR’s instructions to enginemen:

The speed when putting in the scoop to pick up water must not exceed 50mph. The water will go into the tender when the speed is about 20mph and no more will be picked up at 50mph than at 25 or 30, but rather less, because at the higher speed the water heap up at the back of the tank and overflows before it has time to settle down level.

Doubling the speed more than doubles the pressure of the water on the nose of the scoop. At 30mph the pressure on the scoop when in the water is about 5cwt ad 60mph the pressure is 20cwt

Drivers should examine and try the working of the scoop when over a pit, before each trip.

As well as the section of trough, we also have a pick up scoop.  This comes from the tender of 6023 “King Edward II” and was removed when there was a possibility that the locomotive could operate on Network Rail. As the Society can reach more visitors by hiring locomotives to other heritage railways, the scoop will be refitted to 6023’s tender, another step in increasing the authenticity of the locomotive’s condition.

Photographs show trains picking up water at Goring troughs.





No. 3822 – Built To Serve

Sitting in the running shed at Didcot is a huge and powerful beast. At the moment, she is resting, awaiting her moment in the works again after the Heavy Freight Gang has finished the restoration of No. 7202. This locomotive, despite being one of the youngest engines in the shed has an impressive history.

No. 3822 is the number proudly displayed on her cab sides but as you cast your eye over this monster 2-8-0 tender locomotive a few things don’t quite add up. She is undoubtedly a GWR design. Despite her less glamorous purpose as a heavy freight locomotive, the elegant lines of the Standard No. 1 boiler and the brass safety valve bonnet clearly show this. But as you look at her, the first thing that is noticeable is that she wears an unusual livery. These locomotives were often painted black in British Railways days but she quite clearly wears the GWR legend on her tender. Furthermore, as you look up those cab sides you can see that there is a hole for a window but it’s plated over with a sheet of steel. This isn’t just a heavy freight machine - this is a war machine. This is a soldier of the home front and it’s a part of WWII history that is often overlooked.

No. 3822 is a member of the illustrious 28XX family of locomotives that date all the way back to 1903 and the first of the 2-8-0 heavy freight locomotives to appear in the UK and was designed by none other than Mr George Jackson Churchward. The prototype machine as originally numbered No. 97 but when series production began in 1905, she became the first member of the 28XX Class as No. 2800. In this first batch 84 were built, the last one - No. 2883 - appearing in 1919. When Mr Churchward’s successor, Charles Benjamin Collett, needed more heavy freight locomotives with the looming spectre of a new world war on the horizon in 1938, a slightly updated version of the spectacularly successful design called the 2884 Class began construction. Another 83 were built with the last one being turned out in 1942. The world was in a very different situation to the one that No. 97 was born into in 1903...

The railway that No. 3822 first turned her wheels on was no longer the place where speed records, luxury and glamour were the watchwords. Gone was all this to be replaced by the need to get war materiel to the right place at the right time. Gone were the traditional green liveries, replaced by the somber austerity black colour. The cab windows had been taken away and plated over in order to prevent the searchlight like glow of the fire of the engine working hard being seen by enemy aircraft, leading them in to a target. In fact the whole of the cab received a kind of heavy canvas tent like structure to prevent the light reaching the skies. A replica has been made for No. 3822 in preservation and when you see it in place you are immediately struck by the lack of two things. The ability to see out of anything but the front cab windows and the ability to get fresh air into the cab.

The position of locomotive crew was a reserve occupation in WW2. This meant that despite the call up to military service of tens of thousands of men across the country, due to the huge amount of skill and knowledge required to operate a steam locomotive on the rail network of the time, they were expected to carry on doing their jobs. Bear in mind that you are doing all this work in a cab that has become akin to an oven, that you can barely see the track ahead because of both the restricted view afforded by the screens and the blackout in general and you were doing all this on regular wartime rations. Oh yes, and your shifts are now super long too. The railway is now absolutely clogged with freight trains. It all had to be there immediately or sooner and couple that with situations whereby the track was under attack from enemy bombing raids and you get a recipe for some very extended timetables.

It wasn’t unusual for a crew to have to work a locomotive beyond its usual limits and pull loads far greater what it would do normally. If you weren’t doing that it was also not unusual for a crew to join a train in a goods loop, waiting for authorisation to proceed and twelve to fourteen hours later get of the engine perhaps having not moved at all. Hours and hours of work in dreadful conditions with a lack of food and sleep and driving along a railway that possibly ended in a bomb crater 100 yards ahead that the blackout was concealing. There was a speed restriction of 60mph in effect on the entire UK rail network as well. This didn’t help make the timetable situation any better, especially as the long, largely un-braked freight trains were limited to 25mph even before the war. Despite this, stories of trains being chased into tunnels by enemy aircraft to act as a makeshift air raid shelter were not unheard of.

The risk to life and limb wasn’t just in the cab of the locos either, each train had a guard on board. If the loco crew were caught out in an air raid, they may get a minimal amount of protection under their engine but the guard was in a wooden bodied vehicle... The UK railway was the stage for some quite remarkable acts of heroism, the best know of which has to be the sacrifice and stoicism shown by the crew of an LNER munitions train at Soham, Cambridgeshire in 1944 that caught fire. The crew of the train and the local signalman managed to uncouple the burning wagons and pull them away from the village saving many lives but at the cost of the life of Signalman Frank Bridges and Driver Benjamin Gilbert. The crater left when the small portion of the train exploded was 66 feet (20.1 m) in diameter and 15 feet (4.6 m) deep. It demolished a lot of the railway infrastructure around it including the station. In an astonishing display of resilience, there were freight trains running a mere 18 hours after the incident and a full service was running the next day.

Born into war, No. 3822 tells the story of her conflict. Along with No. 5322 (a WWI veteran), they have the privilege of carrying the history of the Great Western Railway and the two world wars. Next time you look up at them, take a moment to remember that they are in effect rolling war memorials. Whilst we today naturally remember the victory of 1945, we must never forget or take for granted the blood, sweat and tears shed in order to secure that outcome. Lives were laid down by both the enlisted personnel and those who fought on the home front, keeping the nation safe and the war machine running.

It is perhaps also fitting that we consider this aspect of the past, given the current world situation. Let us also spare a moment too for the soldiers protecting us today on the medical front line of our modern home front. Keeping them moving? The railways are helping to get those key workers to and from their battlefronts. Many of our volunteers at Didcot are also employed on the modern railway as part of their day job. The railway continues to serve.


Lest we forget...

The danger to locomotive crews was such that Didcot Shed was provided with an Air Raid Shelter to keep enginemen safe.  The original shelter now houses a AV experience so that school children and other visitors can get an impression of what it was like to ride out an enemy attack.



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