onsdag 12 april 2017

Which is Britain's favourite steam locomotive class?

Which is Britain's favourite type of steam locomotive? Flying Scotsman is clearly the most famous, but as a sole survivor of the A3 Pacifics, it is out of the running.

The Gresley A4 Pacifics have an obvious appeal, and fortunately it is still possible to see several of them lined up together, but with their streamlined casings they do not conform to the pattern of the archetypal steam locomotive. The same applies to the unrebuilt Bulleid Pacifics, the appearance of which was a successful attempt to get away from that archetype at a time when it was commercially necessary to update the image of steam.

Surprisingly, LMS Class 5s, with the most survivors of any class, have more of a following than in the days of steam, when they were commonplace, neglected and ignored. Looking at the type in their present-day immaculate condition, however, their elegance and perfectly balanced appearance is evident.

Then there are the Great Western classes, which survived in large numbers thanks to the good fortune of having been sent to Barry. Here of course the obvious candidates are the Kings and the Castles. The former are imposing but the design pushed the GWR's four-cylinder 4-6-0 formula to the limit and they originated in a desire for publicity as much as for the needs of the traffic; the huge boiler sits uncomfortably and the inside/outside framed (and initially troublesome) bogie is an oddity which was the result of having too much to squeeze in. Which of course leaves the Castles, another class which has survived in large numbers. The single chimney variant is as nearly visually flawless as any practical machine can be. To judge by the number of Youtube videos of simulations which bring Castles to such improbable routes as the West Highland, and the West Coast Main Line north of Carlisle, one wonders if the type is not now at the top of the list.

söndag 26 mars 2017

Professor W A Tuplin

Professor W A Tuplin (1902-1975) was an engineering academic and specialist in the design of gears. He worked for the vehicle manufacturer David Brown, eventually becoming Chief Engineer before being appointed Professor of Applied Mechanics at Sheffield University until he retired in 1968.

In addition to contributions to journals, Tuplin was the author of many books about steam locomotives, including Midland Steam, Midland Steam, The Steam Locomotive, Great Western Power, Great Western Saints and Sinners and North Eastern Steam, Great Northern Steam, Great Central Steam, Tuplin's large output meant that he was widely read amongst the interested public, but he was not a locomotive engineer. His sometimes controversial opinions brought him into conflict with practising engineers such as E S Cox and Ell, who was responsible for the redesign of the King and Castle classes in the early 1950s. Consequently, his views need to be read with caution, if not taken with a pinch of salt.

However, and subject to that caveat, it is instructive to read Tuplin's comments on particular classes, including some which have been selected as prototypes for replicas. Even the best machines have their weaknesses, and some of the selected replica types are referred to in his writings. Those who are engaged in these projects could usefully comb through Tuplin's observations. It seems pointless to perpetuate faults in brand new locomotives when small modifications could get rid of the defects without affecting their appearance. Some of the proposed replicas might be of designs which would be best left as memories rather than re-created at full size in new metal.

onsdag 22 mars 2017

Big Green Machine

One night in August 2007 this was heading a construction train in connection with the installation of a new bridge on the Swiss railways at Thayngen. The steam engine proved popular for permanent way and works trains especially at night because it is practically silent when stationary and less obtrusive when working, which was appreciated especially by local residents.

This was not the whole story either, because unlike a diesel, which is constantly idling even when stationary, no fuel is used while in standby mode. When all the sums are done, it turns out that the greater thermal efficiency of the diesel is negated by the cost of processing the fuel to make it suitable for use in an internal combustion engine, and in these standby losses. Hence it has been found that on the Swiss and Austrian mountain railways where both steam and diesel locomotives run on the same diesel fuel, the former use less as they consume nothing when stationary or running downhill.

The locomotive was rebuilt from a German Kriegslok constructed in 1944 and intended for no more than a few months' service. The work was carried out by the Swiss engineering company Dampflokomotiv- und Maschinenfabrik DLM AG of Winterthür. Improvements were incorporated to provide for quick startup and efficiencies around 50% higher than the best that was being achieved when steam locomotives were last used regularly in the 1950s.

Steam locomotives are in many ways ideal for rail traction, where demand for power is intermittent, for example, when starting, accelerating, and on uphill stretches of route. Because the boiler acts as an energy reservoir, the conversion of the chemical energy in the fuel to mechanical energy is separated off from the use of that energy to provide traction. In an internal combustion engine, on the other hand, the engine where the conversion of fuel to mechanical energy takes place has to be sufficiently large to provide for the maximum power demand. And being external combustion devices, steam locomotives are not particularly fussy about the fuel that is used. The use of waste materials is relatively simple and thus the machines can be carbon-neutral.

Steam locomotives are in principle simple, with direct drive from the cylinders to the wheels. By contrast, internal combustion engines used for rail traction require a complex and expensive electrical or hydraulic transmission system, with consequential high manufacturing and maintenance costs and energy losses. Given a reasonably long production run, the cost of steam locomotives should be less than 40% of the equivalent diesel electric.

Unfortunately, there were no takers for the technology, which still has to recapture its credibility amongst conservative railway managers who dismiss it as obsolete. It is unfortunate, however, that the obvious advantages when used, as here, for maintenance trains, have not been recognised.

tisdag 21 mars 2017

The strange case of the Lord Nelsons

The Lord Nelson class should have been an immediate success. Under Maunsell's leadership, the Southern Railway had a first-rate design team with a good record of producing successful new designs and improving existing ones. The prototype was thoroughly tested before series production was put in hand in 1928. The picture shows 854 Howard of Effingham at Waterloo; the locomotive must have been almost brand new, and smoke deflectors had not yet been fitted.

Yet they were disappointing, and despite efforts to improve them, only really came near their potential when Bulleid took over from Maunsell as CME of the Southern Railway in the late 1930s. Then came the war, and afterwards there were so many Bulleid Pacifics that with only 16 locomotives in the class there was little opportunity for them to show their potential. They had very long fireboxes and the rear half of the grate was level, and for that reason they were difficult to fire. Four sets of valve gear for the four cylinders was necessary as the cranks were set at 135 degrees to give a more even beat, but it sounds like an unnecessary complication. The prototype, 850 Lord Nelson, was preserved, and has been restored for main line operation.

One wonders why the design did not closely follow the GWR Castles? The Southern Railway's design team included Holcroft, who had been at Swindon from 1906 until he moved to the South Eastern and Chatham at Ashford in 1914, and would have been familiar with the extended testing and development work which produced the Star class, the predecessors of the Castles.

Background to the design
Extracted from J. Inst. Locomotive Engineers Volume 38 (1948)

In December 1924, Maunsell wrote to the CMEs of the other British railways to ascertain the maximum axle load permitted on their lines. Hughes had submitted three designs on the LMS where the driving axles carried a load of 20 tons which, at the time, was the extreme load permitted on the LMS. Gresley stated that the highest axle load in use on the LNER was 20 tons 16 cwt., and Collett, from Swindon, said that 20 tons was the maximum built to at the time, but new engineering work would permit loads up to 22 tons. Maunsell investigated every channel both at home and abroad to see whether such an engine of the power required could be built within the weight laid down by the Civil Engineer.

The original scheme for an engine which ultimately led to the construction of the Lord Nelson had an axle load of 21 tons 10 cwt., which was 17 cwt. in excess of the 20 tons 13 cwt. of the final Lord Nelson. The cab was rather a departure from the usual Southern Railway cab, being more in keeping with the old North Eastern. To enable the weight to be reduced, the boiler barrel was shortened by approximately 10 in., and this enabled the King Arthur tubes to be used as the distance between the tubeplates was identical.

The improvement made by the alteration to Engine No. 449, particularly with regard to the saving in coal, was so marked that it was decided to incorporate the arrangement in the new "Lord Nelson" class. The arrangement provides a more uniform torque and more regular effect on the firebox draught than is customary and enables the engine to be worked more heavily without fear of 'breaking up" the fire.

The revolving and reciprocating parts were kept light by using high tensile steel, Vibrac, and the balance weight in the wheels was reduced in consequence: this produced a much lighter hammer blow and influenced the Civil Engineer in accepting an axle loading up to 21 tons.

The boiler was large, and a new feature for engines built at Eastleigh was the provision of a Belpaire firebox. The superheater was the Maunsell type with air relief valves. The boiler has probably the widest type Belpaire firebox that could be used within the limitation of the SR loading gauge, consistent with a clear view from the cab; also the longest firebox it is possible for a fireman to conveniently fire. The grate is virtually in two sections, the rear portion being horizontal as a landing and the forward portion sloped. This caused a definite break in the fire and on occasion led to indifferent steaming when inexperienced firemen are used to fire the locomotives.

The Lord Nelson boiler was originally fitted with steel and copper water stays in the firebox. Copper stays were used on the firebox side for the top six rows and the outer end rows only, the remaining stays being of steel. The steel stays were afterwards replaced by Monel stays and this was probably the first application of Monel stays as standard practice to locomotive fireboxes in Britain. The stays are fitted with steel nuts on the inside of the inner firebox.

To enable the engine to be built to the weight allowed by the Civil Engineer, great care was exercised, both in design and actual building. Certain parts normally left as forged or cast were machined to keep within the weight. So much care was exercised that the engine was actually well within the weight when completed, so the remainder of the class did not receive similar treatment. After the balancing of the engine had been calculated at Eastleigh, the figures were submitted to Professor Dalby, who agreed that the engine balance as shown would be very satisfactory in running. Cocks notes that the Southern was unlike the other members of the Big Four: in its intensive passenger services, its electrification and its quest for punctuality. On the rebuilt E and D classes he noted that these shared the large N class piston valves.

...contact with German engineers (in 1930) had an important sequel. They were full of enthusiasm for the solid-headed piston valve with plain rings which had come into use in Germany, and they brought over drawings. This led to their general introduction on the Southern Railway. A snag was struck, however, when these valves were applied to " Schools " class engines working on the Eastern Section.. Certain trains to Cannon Street or Charing Cross have to make a stop at No. 7 platform, London Bridge, which is on a curve and has an up gradient of 1 in 100. To make matters worse, there are catchpoints immediately in the rear of long trains, so that setting back more than a few yards is prohibited. Great difficulty began to be found with the Schools " class in starting their trains and an investigation was made. These engines, in common with the Nelson " class had a lead of ¼ in., but as the solid heads of the valves had a small clearance in the liners, some pre-admission in excess of lead steam started as far back as the first ring, when it passed the port edge. The amount of steam leak was insignificant when on the move, but on starting a heavy load enough leakage occurred to cause a negative turning moment and so seriously affect the tractive effort.

The remedy adopted for this state of affairs was to reduce the lead and transfer the point of cut-off from the edge of the head to the first ring, turning down the diameter of the head in advance of the ring to expose the side of the ring to steam.. This reduction in diameter of the head can only be small in amount, otherwise the reduced bearing surface of the ring in its groove leads to excessive groove wear.

While this alteration ameliorated conditions at starting in the case of the " Schools " class, it was applied also to the " Nelson " class in accordance with the policy of standardisation of parts. In my opinion this was most unfortunate and quite uncalled for from the performance aspect, and I attribute to this the blight which seemed to descend on the " Nelsons " after their earlier brilliance. The alteration did not matter so much to the " Schools," which are customarily worked at a 25 per cent, cut-off and part regulator, but the Western working of the " Nelsons " with full regulator and short cut-off was another matter altogether. Not only was the area of opening to steam restricted by the projecting edge of the head beyond, the first ring but lead steam was reduced as well, so that port opening was much smaller than before, with the same travel. This state of affairs remained until the front end was modified by Mr. Bulleid in recent years.

söndag 19 mars 2017

Hydrogen power blind alley?

Alstom's hydrogen powered train, the iLint, based on fuel cell technology, is now undergoing tests. The train is expected to enter service in passenger-carrying trials on the Buxtehude–Bremervörde–Bremerhaven–Cuxhaven (Germany) route at the beginning of 2018. It is zero emission and promoted as a solution for lines which are not likely to be electrified. The exhaust is pure water vapour.

However, whether hydrogen is zero emission or not depends on how the electricity used to make the hydrogen is generated. There are also energy-efficiency questions which need to be considered. There is an immediate loss, the size of which depends on how the electricity used to make the hydrogen is generated. There is a further loss when energy is converted into hydrogen and back again into electricity in the vehicle, and then there are the usual losses associated with the drive train and control systems.

Nor is that the end of the energy losses. There are also losses associated with the transport of the hydrogen, which is not a portable fuel. It has to be compressed and put in tanks. It will liquify only at extremely low temperatures. What is the overall thermal efficiency when all of this is taken into account? There is a discussion of the subject here, in relation to automotive applications of hydrogen fuel cells.

Then there is the platinum issue. Fuel cells require expensive platinum catalysts. Alternatives are not even on the horizon. Platinum mines are not environmentally friendly. Taking one thing with another, this is nothing like as clean as it appears on the surface.

A good benchmark for cost, energy efficiency and performance would be a locomotive-hauled train using refurbished vehicles in push-pull mode. The fuel cell powered train must cost at least £4 million, and probably much more, not to mention the development costs which must be recouped. In comparison, a small steam locomotive such as the DLM design, which has an efficiency around 12%, would cost not more than £2 million per unit, given a minimum production run of twenty. The locomotive, which can run on anything that will burn but realistically can use diesel oil or biomass waste as fuel, easily satisfies current emission regulations. The use of refurbished vehicles gets rid of the bulk of amortisation charges.

As well as being less expensive, such a solution would be far more capable and flexible than a fixed formation passenger unit of any kind.

When running on biowaste, steam locomotives are a zero-net-carbon technology. What a pity that Alstom did not devote its engineering resources to a simpler and less costly technology. Is this a case of not being able to see the wood for the trees?

lördag 18 mars 2017

Gas laws

Engines - whether driven by steam or internal combustion, make use of the properties of gases. These were well-known by the time steam power was coming into widespread use at the end of the eighteenth century.

The first of the gas laws to be discovered was Boyle's Law, published in 1662, which states that for a given mass of gas at a constant temperature, the volume is inversely proportionate to its pressure.

The second was Charles' Law, or the law of volumes, discovered in 1787 by Jacques Charles. It states that, for a given mass of an ideal gas at constant pressure, the volume is directly proportional to its absolute temperature (minus 273 degrees Centigrade), assuming the system is closed - ie that nothing can get in or out of the containing vessel.

The third gas law was Gay-Lussac's Law, the Pressure Law, discovered in 1809. It states that, for a given mass of a gas at a constant volume of an ideal gas, the pressure exerted on the sides of its container is directly proportional to its absolute temperature.

Adiabatic processes
The term "adiabatic process" is used to describe what happens when the volume of a gas is allowed or forced to change without any heat being added or removed. An example is when the air in a bicycle pump heats up when pumping. The energy from the pumping action heats up the air in the pump. The same effect in reverse is observed when a compressed gas is allowed to expand suddenly, for example, when it is released from a gas cylinder: it cools.

This is the key to understanding what happens when a hot gas under pressure is allowed to expand, for example in the cylinder of an engine. The gas cools, and useful work is done as heat energy is lost, being converted into mechanical energy. The process was analysed by the 28 year old French military engineer Nicolas Carnot. His army career having stagnated, Carnot befriended the scientist Nicolas Clément and attended lectures on physics and chemistry. He became interested in steam engines and what could be done to improve their performance. This led him to the investigations that became his "Reflections on the Motive Power of Fire", (Réflexions sur la Puissance Motrice du Feu) published in 1824, in which he described what became known as the Carnot Cycle. Not only is it one of the core concepts in the theory of engines of all kinds, it is also the basis of the Second Law of Thermodynamics.

torsdag 16 mars 2017

Class failures

There is much that present day engineers, and managers of engineering projects, can usefully learn from the history of steam locomotives.

One is the difficulties associated with novel designs. The novelties do not need to be particularly extreme. Nearly all new engineering designs suffer from teething troubles. But in addition, there are sometimes weaknesses that manifest many years later and affect every single example of the type.

A good example of this is the Merchant Navy class, introduced in 1941. In 1953, a crank axle broke, due to a design flaw which required the withdrawal of the entire class, initially for inspection and eventually for complete rebuilding.

All thirty members of the GWR King class also had to be withdrawn and repaired due to a fault long after they came into service. This was in 1956, nearly three decades after they were introduced. Like the Merchant Navy problem, it was due to fatigue cracking, in this case of the main frames.

The temporary withdrawal of the Merchant Navy class, meant that substitute locomotives had to be drafted in from elsewhere, resulting in some novel appearances. The loss of the GWR Kings caused less of a difficulty as Castle class locomotives could take over, but the examples illustrate the risk of putting all the eggs in one basket.

It is obviously not a lesson that was understood by those who were responsible for the decision to replace the entire surface line fleet of London Underground by a single class of stock between 2010 and 2016. Given that these trains are meant to have a thirty year life, it will be interesting to see how they fare.

How they work - earliest days

Steam engines are, superficially, simple. The chemical energy of a fuel is transformed into mechanical energy by boiling water and using the energy in the steam to create movement. Energy is absorbed when liquid water is transformed into gaseous steam. This energy is known as the "Latent Heat of Evaporation". This latent heat is energy needed to break the forces which bind the molecules of the water together in liquid form; these are particularly strong in the case of water due to what are known as hydrogen bonds, which cause an electrostatic attraction between the water molecules.

The earliest steam engines used only this latent heat. This was the principle behind Savery's engine of 1698. The steam made from boiling water was admitted to a large chamber and the steam condensed by cooling it. This created a vacuum and water was drawn into the chamber. It was not particularly effective, but the idea was developed by Newcomen, who replaced the chamber with a piston and cylinder, and used a spray of water to condense the steam. This was the driving force behind the atmospheric beam engines which began to come into use around 1712 for pumping water out of mines. They did not make efficient use of the energy but in coal mines, where they were mostly used, there was a plentiful supply of fuel that was not of good enough quality to be sold.

About fifty years later, working at the University of Glasgow, James Watt improved the engines by introducing a separate condenser. This meant that the cylinder was not cooled down after every stroke, thereby reducing the waste of energy. Although the early Watt engines still used steam at atmospheric pressure, there was an increase in efficiency as the steam was able to expand in a cylinder against a vacuum on the other side of the piston.

In 1776, Watt went into partnership with Matthew Boulton and they set up a manufactory in Birmingham. By this time, improvements in engineering techniques had made it possible to produce accurate components, especially the pistons and cylinders which were critical if the machines were to perform efficiently. In the final years of the eighteenth century, Watt and others made other important improvements, including "double-acting" cylinders which used steam on both the "up" and "down" strokes, devices for admitting the steam to the cylinders automatically (valve gear), and the application of connecting rods and cranks to convert reciprocal motion to rotary motion, in the first place to drive flywheels.

There is a curiosity here. Because the connecting rod and crank were the subject of patents, Boulton and Watt developed a "sun-and-planets" arrangement to transform reciprocating motion to rotary motion. However, Joseph Needham, an expert on Chinese technology, writing in the 1950s, discovered that connecting rod/crank arrangements used for corn grinding were well-known in China by the end of the first millennium, and in Europe by the middle ages. Foot-operated potters' wheels are also ancient, which makes one wonder about the patent.

The next major improvement was the use of pressurised steam. The advantage is that water under pressure boils at a higher temperature, which means that the hotter steam, which contains more energy, can undergo more expansion before it is cool enough to condense.

Although "strong steam" had been advocated for several decades before it was adopted, Watt was opposed, partly for safety reasons, as the materials available at the time were not reliable. High pressure boilers were liable to explode. This held back development, but by the beginning of the nineteenth century, high pressure engines - using steam at three or four times atmospheric pressure - were practicable. Being more compact, they could be used as a replacement for horses to drive vehicles on the improved roads of the time, as well as on the network of tracked waggonways which were developing around coal and tin mines.

Fictional Ferrosaurs - Thomas updated

A few years ago, children's favourite Thomas the Tank Engine was attacked by a Canadian academic for its "conservative political ideology" and failure to adequately represent women. It was in the Daily Telegraph, so could have been a spoof (see link at bottom). Had it been April 1st, one could have been certain. But then again, such things are possible.

Apparently the trouble is that the engines have boys' names and the carriages have girls', such as Annie and Clarabel, which makes it sexist. Eventually came Daisy the railcar, which solved the problem a bit, but she took a long time to settle down and could misbehave at times.

A lot has happened since the last Thomas story was written, what with the railways being privatised and so many new trains replacing the old ones. There are real possibilities here. How would the engines react to have to share their shed with a stinker like a Voyager? Here is an attempt to bring things up to date.

Latest news from Thomas...
When the Big Railway was privatised, many of the old trains were replaced after a while. Some of them came to live on Sodor. First to arrive were the two emus, called Biggie and Ciggie, who came with a diesel locomotive called Edgar. But Edgar turned out to be not very strong because he really needed electricity to go properly, and as there wasn't any, the Scottish twins Donald and Douglas were put in charge of Biggie and Ciggie. They are only used during the summer as they have no steam heating. Biggie and Ciggie have become very popular because the seats are comfortable, and passengers like to travel in Biggie's buffet car where they serve teas with scones, cream and home-made strawberry jam in the afternoons and real draught beer in the evenings.

After the trial on the branch line with Ciggie, Edgar was used inside the carriage workshop, where he could run when he was connected to a long cable and plugged in just like a vacuum cleaner. He has turned out to be quite useful, but he is hardly ever seen outdoors.

A few summer visitors have helped out for a while. Thumper came for a few months whilst Arthur was having his overhaul, and the next season came Jack Spratt, who was very thin and sounded like Thumper. Jack was used on the main line whilst Henry was getting new tubes for his boiler.

Foreign friends
There have also been a few foreign visitors who stayed for a while; unlike humans, engines from different countries can talk to each other perfectly well. Hermann had three domes and would never talk about the work he had done, which made the others suspect he had done something very bad in the past. Maurice smelled of garlic and boasted about how fast he was, but was quite nice really. Everyone liked Sven, a quiet and friendly little tank engine with big headlamps, who wore a red snowplough even in the summer and smelled faintly of a mixture of cinnamon and coffee. Sven, a distant relative of Arthur, was very clever but never said much except when the others admired his delicately machined rods and red wheels. Then he would nod in agreement and once said, modestly, "Not bad! They made a good job of me, didn't they? Look at my oil cups - they have proper metal covers instead of the corks you've got."

When engines are left on their own together, they often talk about coal, of course One night, Duck mentioned that Welsh steam coal was the best and that he hated the taste of anything else. This led to an argument, as Donald and Douglas disliked any coal that did not come from Scotland. Sven, who so rarely joined in a conversation, mentioned that he had been fed with logs of wood for a while. He said that they tasted delicious, and were cleaner than coal. They were not dusty and the smoke smelled nice, but he didn't feel so strong as when he was fed with coal.

Zoltan the Hideous

Another foreign visitor was Zoltan. The others all felt sorry for him because he looked so hideous and sad. He had an ugly face, pipes grew all over his boiler like ivy on a tree trunk, and he had two domes joined by a big pipe. Zoltan looked battered and was painted dull black. They wondered whether he was sad because he was ugly or if being ugly made him sad. One night he told them all about himself. He had run on the Emperor's railway, but then he had been sent to a place where the water was so dirty that all the engines got boiler-ache. That was why he was fitted with an extra dome and the pipe in between. He had also worked for the army for a long time and was badly treated. He was sad because of some of the things he had been made to do.

"You shouldn't worry about what you look like", said Thomas, trying to cheer him up. "You could easily get a new shape. "

Duck piped up, "Lots of engines have been in the army. My old mate Rod was always telling stories about the things he had done. It's a pity, though, that you never went to Swindon. You would have come back with a nice tidy tapered boiler without even one single dome, a brass safety-valve trumpet, a copper-capped chimney and a neat cab. Engines that went to Swindon always came out with the proper domeless Great Western look. I hate domes."

"Haha! Talk about domes", said Henry. "You and Oliver have got bigger domes than any of us. Have you seen yourself? Great Western engines either have a huge dome or none. The rest of us have proper-sized domes."

This business of domes was a sore point with all the engines, but especially for Duck. It was best not to talk about it. Duck was very proud of his dome and whenever he passed the station buffet he would try to steal a glimpse of it, reflected in the windows.

None of this left Zoltan feeling any happier. "It isn't just my domes and pipes that make me look so ugly. There's my cylinders and valve gear too. I just look completely wrong. I'm the ugliest engine in the world." He started to sob.

These engines were just shed company for Thomas and his friends, because when the Fat Controller measured them, he found they were too big to run on the railway. They used to be taken out into the yard on special days and run around a bit so that visitors could look at them but in the end, they were sent back to their own countries.

Hans and Hank
Then there was Hans. He was bigger than Gordon, slightly streamlined, and looked very smart. His boiler and cab were not painted but left in the natural silver colour of the metal, which was kept polished. His wheels and rods were painted bright red. He always spotless even after a day's work. No speck of soot ever came out of his chimney. He was too big to run on the railway but worked on his own in the yard every day. He moved about very quietly. The other engines did not know what to make of Hans at first and thought he was stuck-up and unfriendly. Thomas cheekily asked him if he was really a steam engine. "Yesss!" hissed Hans, irritated. Thomas asked him where he kept his coal, as he couldn't see anywhere for coal on his tender.

"I don't burn coal", said Hans. "I burn diesel. Just like you burn coal. I am very strong, clean and quiet. I am cleaner than any diesel. I use less diesel than a real diesel. I used to burn coal but oil is easier. Incidentally, I am much older than you think I am. I am older than some of the rest of you. I started off in the army so be careful how you talk to me."

Hans impressed everyone, especially the Fat Controller. They could see that he had been telling the truth. But one morning, after he had been for a few weeks, Hans woke up with a worried look on his face. "It's my last day today - I'm off home to Switzerland tomorrow. There's a lot of work for me to do on the big railway there. I am going to be tested. I have got to compete with a diesel."

After breakfast, he puffed out into the yard outside. There was a tremendous racket to be heard. It was a visitor who came to a stop on the track next to Hans. Two columns of blue-black smoke were shooting out of his roof like a volcanic eruption. "Hiya! Hank's the name." Hank was painted a red-brown colour, the same as the soft drink he was advertising. The name of the drink was painted in white flowing letters all the way along both of his ribbed sides, and he looked just like a giant soft drink can himself. "You all think yer better than me buchoo ain't. I'm the greatest'n ahrm gonna prove it." He spoke in a loud drawl.

The two engines spent the day doing heavy jobs, and when they had finished, they played tug-of-war. Hank screamed for all he was worth, whilst Hans was almost silent, but neither budged, and in the end, the competition was declared a tie.

Emmie and Tracey arrive
Then came a whole season when nothing went right. It started just before Christmas, when Hank turned up again one frosty morning, this time with six shiny white and green carriages, and the special purple vans called Hatch and Match, one between Hank and the carriages, and the other at the back. The Fat Controller came out with Daisy's driver to meet them and looked doubtful when he saw Hatch and Match. Their presence was always a sign that the trains were going to get up to mischief.

Hank uncoupled the front four carriages from the others. This is Emmie", he drawled. "She ain't said nut'n since ah picked 'er up. Just a squeak now n'then. I wuz told she was sometin called Lectrostar." Hank screamed off trailing blue smoke behind. The carriages, obviously brand new and fresh from the factory, stood silent.

Emmie was wearing a lot of make-up, with fluorescent lipstick, dark eye-shadow, and long artificial eyelashes. The Fat Controller and Daisy's driver climbed into the cab. It was freezing cold inside and smelled of new plastic. They looked into the passenger compartment, where the seats and carpets were all carefully covered with polythene sheets. In the cab were rows and rows of switches, more rows and rows of coloured light bulbs (none of them lit), and rows and rows of buttons. The Fat Controller looked at his reflection in the grey computer screen. On the cab window was stuck a piece of paper saying that the train should not run with carriages with a different version of the windows. Daisy's driver, walked the length of the train and back and shrugged his shoulders, then he got back into the cab and pressed a button marked "standby power supply". Nothing happened. The Fat Controller shook his head from side to side. He climbed out of the cab and checked the label pasted onto the side window. In the space for the destination was scrawled "Sodor" in untidy handwriting. He put his reading glasses on and checked the label again. "Sodor", it said.

Then he noticed a big brown envelope tucked beneath the driver's desk. He opened it and went through the wad of papers inside. He showed them to Daisy's driver.

"Look! It says Sodor on the label all right. Doesn't it? But this piece of paper is typed out and it clearly says Selhurst. Have a look", said the Fat Controller. He wasn't sure now.

They had another look at the label on the train. It could have said Sodor, but then again it might have said Selhurst. They couldn't decide. In the end, the Fat Controller said that Emmie had to be got out of the way and he asked Donald to put her in the carriage sidings with Hatch and Match.

Then he went over to the other train. She looked almost the same as Emmie, with too much makeup on. Again, he checked the label and again he couldn't decide whether it said Sodor or Selhurst, so he went through the other papers in the envelope and it turned out that this train was in the right place. "She's here for testing", said the Fat Controller to Daisy's driver. "The Big Railway is too busy so it is being done here."

"Hi, dude! I'm Tracey the Turobstar. I'm good at everything". She had begun to burble to herself in a in a boastful tone.

Donald had come back wondering what to do next, but the Fat Controller sent him away for a drink of water and asked Daisy's driver to take Tracey to the shed.

Tracey the troublesome
There were quarrels almost immediately. After a few days, the conversation one morning went like this.

Thomas, "Ooh, you nasty girl! You smell of diesel! And you are keeping us awake by running your engines all night long. We have been tired in the morning ever since you arrived. You don't belong here. We know. Go back to the Big Railway."

"I need to keep my engines running so that the cleaners can vacuum my carpets", she snarled. Tracey ran her engine up to full speed and spouted black smoke all over Thomas.

Thomas blew off steam from his safety valves,

Tracey replied, "I don't like noisy steam engines. They belong in museums."

With a blast on her two-tone horn, she set off for her day's work - she had been given a job on the branch line for the time being - rumbling and muttering.

One chilly January morning, Tracey threw a tantrum while out at work, and refused to budge. She fell silent in a sulk. The Fat Controller had to order buses so that the passengers could finish their journeys, and sent for Thomas and Match to tow her back to the shed, where she carried on sulking for the rest of the day.

Oliver came to the rescue. The passengers were delighted to see him again, with his old autocoach called Isabel, and he puffed happily up and down the branch line with her all week, until Tracey felt like working again. But she was very lazy and temperamental and in the end she couldn't do any work at all as she needed a special spare part which had to come from Germany. So it was decided that she should be sent back as soon as possible to the Big Railway, together with Emmie, who had never moved since the day she arrived. The move was delayed because a family of robins had nested between two of the carriages and they had to wait until the chicks had flown before Emmie and Tracey could finally go. All the engines howled and shrieked and hooted with joy as Donald and Douglas towed them away. They were never heard of again.

How Thomas and Vera fell out.
Worst of all was Vera the Voyager, who arrived on her own during the half-term holidays that February. Vera had a deep gruff voice and smelled of drains as well as diesel. She didn't sound anything like a girl. "I'm really fast", she growled. "I can lean over when I go round curves."

Gordon hissed, "I'm nearly as quick as you and I can pull lots of carriages. You can't pull anything at all and you've only got four carriages of your own. People have to book up weeks beforehand if they want to travel on you. And the Fat Controller has to charge them more. There's no room if a lot of people want to get on."

Vera gave a little shudder and let out a burp. She had bad manners. "I don't need to pull carriages. The passengers can sit inside and I go ever so fast. I've got computers. Dozens of them. And a shop. And every coach has its own engine. I cost five million pounds, so there!"

"H'mm", sighed Gordon. "I overheard people on the platform grumbling about you yesterday. They said the seats were too close together. They often had to stand because you were full up. They couldn't see out of the windows. There was nowhere for their luggage. Your toilets were often blocked. You bump and shake the passengers as you go along. They said they would rather travel in my comfortable old carriages, with me pulling them. And you smell of poo. You shouldn't be sharing our shed with us. You take up as much space as three engines. Sir Topham Hatt could have bought lots of us for the money you cost." Off Gordon puffed to get his carriages.

The Engines' Revenge

Vera was with them all that summer and by the end, the other engines had had enough. One windy autumn night, they decided it was time to get rid of her. They hated Vera, with her bright red paint and smug, leering face, smothered in lipstick. They were tired of the bad smells she gave off. She often woke them when she came back late from her long trips, and then kept them awake by running her engines. Thomas said she was flashy, dirty and stand-offish. She wouldn't even couple to them without having Hatch or Match in between. A plan was worked out. Next day, James was going to take a train on the line that ran along by the sea. It was his favourite route. It was easy work because the line was practically level. The track was built on the old sea wall and ran in and out of tunnels through the red rock, past little coves and along wide beaches. It was a beautiful stretch. During the summer, children on the beach would turn and wave to James as he puffed past, and James's driver would wave back and give a toot on his whistle. But when the sea was rough, the waves splashed right over the track and made James wet, but he never minded, even though water sometimes ran down his funnel. Many times in the winter, the cleaners had emptied bucketloads of seashells from his smokebox.

When James's driver came to collect him in the morning, James pretended he had boiler-ache. The Fat Controller said he would give James and his carriages a rest and sent Vera instead.

"No", growled Vera. "I only go on long journeys. And I don't want to go along that nasty line next to the sea. It makes me feel seasick."

"The people will like you. You are new". The Fat Controller knew she liked to be flattered, though he had heard the complaints too, and that she didn't like to go near the sea. But he insisted, and so off she went. But when she came to the stretch of line by the sea, a huge wave washed right over the line and water poured all over the engines and the other works under her floors. Vera spluttered and came to a stop, whilst the spray from the big waves continued to fall on top of her. By then, and it was later in the morning, James was feeling better and the Fat Controller sent him and his carriages to collect her passengers. They were very pleased to see him and all waved and cheered.

Duck was sent to collect Vera but she would not let him pull her. "I'm not going to be pulled by a dirty old-fashioned steam engine. I won't even let myself be coupled to one. You should know that", she said, in a low, hoarse voice. "Go back and get Match", she said bossily. Duck was angry and felt insulted. His green paint was, as always, fresh and shiny. He was very proud of his appearance. The copper cap of his chimney, and his pretty brass safety valve trumpet, were always polished in true Great Western fashion. It wasn't just him that was being insulted; she was insulting everything Swindon and everything Great Western, and on his very own stretch of line, too. He wouldn't have it. With a roar, he let off a jet of steam at Vera and puffed back to his shed to get Match. When he came back, Duck gave her as hard a bump as he dared, and then dragged her back to the sheds. She was a sorry sight, with sea water running out under her doors and swags of seaweed draped over the openings in her roof.

What happened to Vera
"What are we going to do with you?", asked the Fat Controller, scratching his head. "I'd send you for scrap if you weren't so young and hadn't cost so much."

He told Duck to shunt Vera into the sidings where he put the carriages to wait when they needed to be repainted. Vera stayed there, next to Emmie and Tracey, for several months. By the end of that time, ugly streaks of rust were showing through her red paint, the seaweed on her roof had gone dry and her roof was covered with bird droppings.

Towards the end of the winter, Edgar was sent to collect her and shunt her into the workshops. They took out her engines and carted them away, where the metal was melted down and made into garden furniture. Her computers were carried out and given to the local school. They cut off her ugly nose and gave her flat ends like ordinary carriages, with proper buffers so that they didn't need Hatch or Match if they need to be coupled to the engines or any of the other carriages. The holes in her roof were covered up. They gave her new windows that the passengers could open if the weather was fine. They took out some of the seats and spaced out the rest, so her carriages were comfortable for the passengers, and fitted her with steam heaters and vacuum brakes so that the steam engines could pull her. Each of her carriages was given her own name: Barbara, Bella, Bertha and Betty. And to finish it all off, she got a new coat of dark red paint with fine gold lines all the way along the sides. When all the work was done, they looked perfectly respectable. Duck came to collect her and she was shunted into the sidings with all the other carriages.

Next day - it was the start of the Easter school holidays - Gordon came to collect his train. At the front were Barbara, Bella, Bertha and Betty. "Gosh, how smart you look", he said. "I can hardly recognise you. You are the smartest carriages on the line." Everyone was very pleased with them. The other engines envied Gordon because he was the only one allowed to pull them. The other carriages, too, were a bit jealous at first, but they quickly settled down to their new job.

Stan the new engine

The Fat Controller was pleased at the way things went after he had dealt with Vera. One day he came into the shed and told the engines some news. There was going to be a visit from a brand new steam engine. It was a relative of Gordon's, called Tornado. In fact, he looks very much like Gordon, except that he is painted green, he explained. Then he told them about Stan. The Fat Controller said he felt sorry for the engines as they often looked tired. The truth is they were getting old and it was bad for them to be working so hard all the time. Stan was going to come and join them - when he was finished.

"What do you mean, when he is finished?", asked the engines in chorus.

"Stan is being made", replied the Fat Controller. "People are starting to build steam engines again, specially for lines like ours, but perhaps the Big Railway will have some too. He will be brand new when he arrives at Sodor. If he behaves well, I shall get more, the same as Stan. Together, we shall show the people on the Big Railway how things ought to be done."

"What does he look like?" they asked.

"Something like Arthur, but slightly bigger. You know how useful Arthur is. He can do most things quite well if they are not too much for him. Well Stan will be a bit bigger and stronger." He will be able to push and pull Biggie and Ciggie, the same as Oliver does with Isabel.

The other engines asked what would happen to them. "Don't worry", replied the Fat Controller. "When Stan and his friends arrive, you will only have to work on special days".

Article in Daily Telegraph.

onsdag 15 mars 2017

New build steam

There are at present around twenty projects for building new steam locomotives, replicas of designs which did not survive the elimination of steam on Britain's railways in 1968. The creation of replicas, previously thought impossible, has become practicable and relatively affordable due to new techniques and new materials: CADCAM, 3-D printing for patterns, and plasma and laser cutting, SG cast iron, etc.

The A1 Pacific Tornado was the groundbreaker, begun in 1994, it was finished in 2008 and has been used for main line steam specials since then.

The new build proposals are either for locomotives for main line use or for haulage on preserved railways. Most of the choices, however, will be criticised by someone. Every class of locomotive had its strengths and weaknesses and most of them underwent modifications over the course of their time in service with the aim of getting rid of the faults.

Although main line steam is gradually being squeezed off the main lines as regular traffic continues to grow, on secondary routes it is likely to continue for the foreseeable future. Trips behind steam locomotives are as popular as ever, and any locomotive entering service now will have a useful career ahead of it. However, the locomotives have a particular task to do: to haul trains of about 350 tons at speeds of at least 75 mph and preferably 90 mph. In this light, some of the proposals, whilst interesting, are going to result in locomotives which cannot be employed economically, being either too small, or unsuitable for high speed running.

As the generation that remembers steam in service passes into history, there will be a declining interest in particular types familiar from childhood. In twenty years time, most people will be satisfied with a generic steam locomotive, which will not even have to be burning coal.

For my money - and I will stick my neck out here, the most practical generic design remains the GWR Castle class. It is not accidental that construction of these moderate-sized (they weigh only 80 tones and have an axle load of just under 20 tones) but very competent locomotives was spread over 27 years, that the LMS wanted fifty of its own and that eight survive. They seem to have run comfortably at 90 mph, presumably because of the four cylinder configuration. The 4-6-0 wheel arrangement makes them good on hills. With two sets of eccentric-driven inside Walchaerts valve gear and the de Glehn staggered cylinder layout, the Castles are robust and fairly easy to maintain, apart from the large number of oiling points, some not very accessible. Their principal weakness, which showed up in the 1948 trials, and again recent years, is that they do not perform well with poor quality coal. Modifications such as increased superheating and double chimneys were made to remedy those deficiencies, and so the locomotives continued in service until the end of steam.

If we were looking for a standard locomotive for main line steam haulage and seasonal jobs, it would be possible to do a lot worse than build a small batch of Castles with a few tweaks: light oil firing to get over the fussy taste for coal, roller bearings, perhaps, improved materials including the use of stainless steel for some components, better lubrication arrangements and a general review of the details of the design in the light of over 90 years of experience.

To judge from the amount of noise they make, there is probably some energy wasted in the exhaust. Recent experience with the restored King class 6023, restored to its original single chimney form, and a new 4-nozzle exhaust arrangement designed by J J G Koopmans, suggests that there is still room for improvement to the draughting. The last of the unrestored Castles, 7027, never received a double chimney and, with renovation now in progress, would be a good candidate for a similar modification to optimise its performance.

Museum lines are another matter. They have a very specific requirement - they operate trains up to about 250 tones at fairly slow speeds on hilly routes with runs of up to about twenty miles.

This is quite a demanding task and was typically done by locomotives of power class 4, such as the 2-6-4 tanks built by the LMS and British Railways, GWR 2-6-2 types such as the 5100 class, or 2-6-0 tender engines such as the LMS and BR 4MT type and the GWR 4300 class. Many of the surviving locomotives are now getting on for eighty years old, and with few examples of each type, spare parts often have to be specially made.

Museum lines are also finding it increasingly difficult to find sufficient volunteers as the original steam age contingent are well into their sixties and more. So the need is for locomotives which are simple, efficient, reliable and specifically designed for the job that they will be doing. Again, the need is probably for a generic type.

That sounds like a batch of the BR or Stanier or Fowler designed 2-6-4 tanks, or possibly a new design based on the best features of all three, or the GWR 5100 class, though possibly with an option for a tender engine version.

What looks more questionable are the replicas of some of the smaller Victorian types. Charming as they are, they might not have the power needed for the work. It is the same reason why engines such as the Bluebell's delightful Adams 4-4-2 tank is, unfortunately, unlikely to steam again.

One of the problems with using steam locomotives intermittently is the effect of thermal cycling. Boilers would last longer if they were kept hot. One way of keeping them hot would be to use the locomotives for undemanding ordinary work when they are not being used for the special trips. If the locomotives were running on light oil, this would get round the difficulties of having to handle coal. This would have the advantage of generating a bit of extra traffic on lightly loaded trains. Swiss experience is that steam locomotives optimised to present-day levels are, in practice, pretty much the equal of diesels.