There’s no denying that while railroads have switched to diesel and electric as their primary power sources, there’s a certain allure to the age of steam. With that in mind, a group of Pennsylvania train fans are bringing the alleged fastest steam train back from extinction.
It takes real dedication to build a 428-ton device from scratch, but these rail aficionados seem to have it in spades. Armed only with the original blueprints and a lot of passion, this team has already finished construction of the boiler and nose of the Class T1 replica which is no small feat. This puts the train at approximately 40% complete.
Some changes are planned for the locomotive including a change to fuel oil from coal and replacing the poppet valves prone to failure with camshaft-driven rotary valves. While not original hardware, these changes should make the train more reliable, and bring the world record for the fastest steam locomotive within reach. If the T1 replica can reach the 140 MPH storied of the originals, it will smash the current record of 126 MPH held by a British train, the A4 Mallard, which would be exciting indeed.
Speaking of Pennsylvania and steam, a trip to Scranton is a must for anyone interested in the age of rail.
Hmm… I feel that making design changes (even for reliability) makes building a “replica” a moot point. Designing an entirely new steam locomotive from scratch using the latest technology and materials seems more in order. Forget 140 MPH, shoot for 250! :)
Steam powers the turbine for maglev drive generator?
I think that rather depends on what you want – a super sci-fi steam train built for those space cowboy out on the frontier planets is effectively what an entirely modern design would appear to be…
Where minor upgrades to the workings is something that happens in service anyway. So for giving a large part of the historic feel of the originals with improved usefulness today this can’t be beat – its more like here are some minor changes made in service because decent coal got hard to import and we had oil, and that part of the running gear failed often so we rejigged it…
I too would like to see just how far modern metallurgy, metamaterials and CFD simulations could push a steam locomotive, but its a whole different game…
The valvegear of a locomotive is pretty fundamental to the functioning of that locomotive. It’s not a minor detail or upgrade. I also doubt if they really have enough experience and knowledge on design a valvetrain for a steam locomotive. Nobody has done it for a locomotive that size for nearly 100 years by now. It’s unclear what exactly the problem with the original poppet valves was. It might be that a very simple redesign of the poppet valves can solve the problem
No denying its fundemental to the function, but valves are also something that has been changed and upgraded historically bringing older locomotives more inline with the the newer ones.
As for knowledge I’d suggest we know way way more than enough to make better valvegear – the old stuff was designed to be very forgiving to manufacturer, as it was made by guys on manual lathes and mills from giant castings that were likely imperfect. The problem is also fundamentally no different to valves handling hot/damp gasses – a pretty common problem still today..
Now making a really optimal valve for this task with a break of 100 odd years is likely to have iterations potentially many of them, but functionally very good one really should be first try with modern simulation and production capabilities and the vastly better materials…
I’m familiar with sliding valves in steam engines from watching videos of people building model engines (and from a hilariously failed attempt to 3D print a working engine of my own) but I’m not familiar with how poppet or cam-driven valves would integrate into the engine itself. If the cam-driven valves don’t work out can they switch to a redesigned poppet valve or is this a design decision that really has to be made once and for all before casting and boring the locomotive’s frame?
In response to both Foldi-One and Henry,
I don’t think there’s a way back once the choice has been made for one type of valve type over another, at least for this project. It was also extremely rare for it to be done in the past as far as I’m aware. The valve placement dictate the mechanics and is a highly integrated part of the cylinder block castings, which themselves are probably the most complex and costly parts of the whole locomotive aside from the boiler. Changing from one valve type to another would likely mean substantial changes to the cylinder blocks, basically requiring whole new castings to be made with all the work, time and cost that involves.
The problem also goes beyond just the valve geometry itself. The whole mechanism driving it has to provide very good, accurate timing with a variable cut-off over a wide range of speed conditions. While we have certainly made strides simulating these sorts of problems and a lot of the computation is nowadays a lot more straightforward due to the wonders of modern computers, really thoroughly understanding the interactions of the entire mechanism and how the valve-train dynamics influence their function and mechanical strength is certainly not a trivial or easy problem even with modern computers.
As to the “old stuff” being designed to be very forgiving to manufacture, I beg to differ. Able to be manufactured with the machinery available certainly but what the tolerances those guys could achieve on those machines was nothing to sneeze at. By the late 30s and early 40s metallurgy was also certainly to the level that the giant castings were of very good quality. Some would even argue better than today. Parts designed then wouldn’t be able to be made thinner or much different from how they were designed then. We can just design them faster, have the master/plug milled out using CNC and have the casting made much faster. In terms of castable steel/iron quality, the materials we have today are certainly much more predictably consistent batch to batch but really not that much better overall and we’re talking tenths if not hundredths of a percentage point variations in alloying materials between batches even back then.
Yeah I don’t know how common it was, BUT I know I’ve seen references to changing the type of valves during a service, which may mean a large amount of alteration to frame as well, I really don’t know. Though keeping the boiler and bulk of the wheel base as is even if you end up cutting out a beam and welding/riveting/bolting in something else is a major win over building a new locomotive if the valves bring the engine up to greater reliability.
As the timing for steam is actually rather forgiving its not that bad in theory to completely rejig an engine’s working methods, as you don’t need sub millisecond timing precision, nor do I expect structural issues to be a great problem. Especially when dealing with the rather over engineered mechanical parts common to the world of steam locomotives. Also historically its far less important what the ultimate efficiency of the engine is, as long as its good enough to be useful – what matters is how reliable it is, if you can’t rely at all on the transportation links and spend more time and effort on maintenance than you can using it…
My point on the old stuff being forgiving to make isn’t at all about what the talented machinist of the past could do, of which there are many great examples of supreme precision. It is just that generally the design for each part is such that only a small number of surfaces actually need any great precision, most can be left as cast. And often the only precision required isn’t even in reference to other areas of the same part – its enough that this slide is flat, smooth and sized to fit its mating surfaces and that rod diameter matches the bushing it runs in, but its not important to be really tight tolerance in the relationships between such high precision areas of the same part. Though as the period of steam is so vast of course its not that simple for every case.
Today however we absolutely can make thinner, stronger, harder wearing and lighter parts than could then – as its now possible to use materials that were not even remotely possible in that period. I’m not saying the old metalworkers didn’t produce great castings or chose terrible materials but its limiting in the extreme to use the same stuff they did for the same parts when now there are so many other options that were not available at all (yet) or at the time super exotic and are now pretty common place.
And I never said it would be trivial in effort to design and build something new – that never is, even for really simple stuff. Just that you can now create a functional one pretty trivially, its not some great research project that has to take many prototypes just to get a working one… Plus if you generate your parametric designs of actually producible parts and let loose the electrons to select the parameters over many generations, compare many designs as well – in a week or two of compute time you have a really damn good and designed to manufacturer bespoke valve. That is likely substantially more optimized even in such a short time than the historical ones, as they had to physically make each generation to get much idea of its real performance – technically you could do the mathematics to get a good estimate, as most of it is sufficiently known long before steam even, but it would take longer than just building and testing the damn part without a calculator.
I’m no expert.
I did however watch a BBC show on the fastest locomotives ever. Apparently it was all about the super heaters, a genius (who’s name escapes me) redesigned several during one of their routine boiler rebuilds and put them into a new class. Larger and more super heater tubes that flowed better. Bigger fireboxes. After that they built new locomotives to his design.
They cared no more for efficiency then current top fuel dragsters do. A loss of efficiency but gain in raw power was a win. Ran the pressures with safety margins that would have the operators making diamonds if they had the foresight to shove a piece of coal into an uncomfortable place.
This was distinct from the separate contest for max weight pulled. Max speed contests pulled short trains that were as economic as F1 cars. They also had speed contests for given routes with passengers, but those were relatively slow.
It’s not a Train!!!!! A locomotive pulls the train. Don’t show ignorance!! As a steam locomotive footplate man for many years starting in 1956 I think I know what I’m talking about! 45 years service..
Changes like these were regularly made to in-service machines during their commercial lifecycle, to make them more efficient, reliable or effective, or relegate them to new tasks.
I have encountered the opposite problem. I sailed on a 1914 ship that was built as 18m long, never accepted by the original owner and then rebuilt to 26m by a new owner before it ever was registered. New regulations made it attractive to rebuild the ship back to 18m, but we will lose our “historic ship” designation which held conciderable advantages (such as lower fuel tax and easier berthing in certain harbours), because the ship is no longer in the “original” condition — even though it would become more original than it was during the last 108 years.
In the end we could not afford to keep maintainenance under regulations for 26m long ships, and she was sold at scrap value (to someone who had a vague plan to eventually make something nice out of it but will probably let it rot away).
Forgive me if I’m wrong, but wouldn’t the max speed depend heavily on whether the tracks and all that entails can bear those higher speeds? I know highways grade their curves for optimal speeds.
You are quite correct in principle anyway you can’t run 200mph on a cheaply built tight and twisty branch line. Along with also needing the traffic controls and priority such that you can actually go that fast on a busy line. That is one of the things that made the Mallard and the City Of Truro’s reported 100mph even earlier so impressive, they were done while in normal service.
Strictly speaking, I don’t think Mallards record breaking run was “in normal service” as I understand it was a special brake testing train with several reporters on board!
Yes, my question exactly. Where in the US do we have several miles of straight track capable of taking a 425 ton locomotive to 100+ MPH. Maybe in Japan or Europe where they have very high speed trains, but the electric engines are much lighter.
Several places in West TX currently have 90 mph speeds for Amtrak and the Northeast corridor is Class 7 track supporting up to 135mph but the goal for this train in 200 mph and no current tracks in the US will support that speed. If the high speed rail projects in CA and TX ever get built (doubtful) they would.
I bet kansas has many miles of track that fits that description.
There are reports of T1s being run at 100+ MPH in rural Indiana in the late 1940s…but that was then. Who’s going to let somebody else’s engine do it on their track today?
The T1 will attempt the speed record at the TTC in Colorado. Their high speed test track was used for the Amtrak Acela.
https://railroads.dot.gov/research-development/program-areas/testing-facilities-equipment/testing-facilities-equipment-0
Meh. Count rivets elsewhere.
There’s one gentlemen that has been working pretty hard on some great innovations to bring steam power back check out Mackwell Locotomove Co to see what I’m talking about :)
Pennsylvania RR aficionado here. The rotary cam design change was actually used on one example of the original T1 locomotive, number 5500. It was involved in a crash, so they rebuilt it with the same rotary camshaft valve gear that they are going to use on the new locomotive. It was supposedly superior to the original setup, but never adopted on all locomotives because diesel locomotives were quickly replacing steam locomotives. Here’s a link to a photo of the the locomotive with the camshafts installed: http://s3.amazonaws.com/rrpa_photos/137164/PRR_5500_I_A-Pb.jpg
Interesting, I never knew that. I love how it makes these locomotives look even more “steampunk”. They’re already using a design language that doesn’t quite match what we expect with the era of steam locomotives (especially from my European eyes) and removing the “normal” valvegear makes it even more strange looking
>> They’re already using a design language that doesn’t quite match what we
>> expect with the era of steam locomotives (especially from my European eyes)
It’s weird how this works, because having grown up looking at American prototypes, I always thought that European locomotives didn’t look quite “right”, probably in part because so many of them had much of their valvegear hidden inside the frames
It’s such tiny design differences that we cue in on
Another change between the two is USA locomotives tend to be rather huge with much larger tender than the European counterparts – the whole scale is different while the rail gauge is generally the same – which really changes how they read when you look at them. In many ways the US locomotives look more like narrow gauge railways, especially compared to the UK with its generally very much narrower loading gauge than the continent.
The world speed record for a steam vehicle is 139mph in 2009, although that was a purpose built car rather than a train.
https://en.wikipedia.org/wiki/Inspiration_(car)
I have a book published about 1986 by Vernon L. Smith; he worked for Franklin at the time the T 1s were designed and they wanted Pennsy to go to the popet valve with the external drive (rotary off the axle, as he was able to do at Santa Fe on 3752) there was a wrecked T1 that got the revision on the front engine only after the collision. Vernon was so expressed with the work of the T1s that he too thought they should have been given the title of Fastest Steam Engine as they frequently made that speed going onto Chicago.
I feel like people don’t understand what a replica is… it’s not an exact one for one. There are thousands of automobile replicas in existence that are repowered, use vastly different and/or upgraded suspension, etc.
As for these guys knowledge… I have the utmost confidence in them. I had one of their apprentices as a welding student a few years ago. They’ve all been restoring and upgrading steam locomotives and early diesel locomotives for decades. A lot of what they know is passed down and added to. They are, essentially, a handful of experts in a field where there are not many experts left.
When have rotary valves ever been a success in otto cycle engines. I think the poppet valves should have been redesigned. remember, when the train was designed was the age of leaded petrol, so the tech for hardened steel valves has progressed on farther.
in 2-stroke engines for the inlet, where they were actually VERY succesful, from the humble vespa to high-end grand prix bikes
Bombardier used them a lot in the 2-stroke Rotax engines used in snowmobiles and watercraft. One big counterweight-shaped rotary valve. They were very compact and worked well.
Ditto for Kart engines in the late ’80s and ’90s. Rotary valves enable higher RPMs than tappet valves. The challenge for rotary valves is cylinder sealing – it’s always a trade-off between sealing and friction. Too little sealing pressure and valve wear soon results in cylinder leaks. For frequently rebuilt engines (such as race engines), that’s not a huge concern. For small engines (e.g. Vespa), the increased friction is accepted. It’s engines that most of us use where rotary valves are rarely seen – you wouldn’t rebuild your car engine every 10K miles, nor could you accept the friction losses required to keep it reliable for 100K.
It’s a real shame that Coates spherical valves never really took off.
This isn’t an internal combustion engine, it’s an external combustion steam engine that originally ran on coal. The valves aren’t exposed to combustion, only steam.
Rotary valves are used in diesel engines that don’t need to vary RPM quickly, such as generators.
As far as I can tell, the pistons in a steam rail locomotive are directly linked to the wheels, no gearing involved. This means that compared to an Otto cycle engine, these engines run VERY slowly. Thus valves and valvetrain do not have to be optimized for very rapid and abrupt flow: smaller and more rugged designs are possible without losing significant performance.
Hawker Tempest, Typhoon, Fury, and SeaFury fighters, Avro Lancaster bomber, Bristol Beaufighter night fighter/attack aircraft, Handley Page Halifax heavy bomber, Vickers Wellington long-distance medium bomber, among many, many others.
I think that the last few comments are on the wrong track. I have been a mechanic for a good portion of my life. The valves on an Otto cycle engine are very different form the valves of a steam engine. On a steam engine it works like a double acting cylinder in which one side of the cylinder is basically open to atmosphere and the other side is connected to steam. As tthe cylinder reaches end of stroke the valve physically slides to cover the open end and uncover the closed end thus pushing the cylinder in the opposite direction. This causes both strokes to be power strokes. Some steam engines have a double piston design where the first cylinder completes it’s stroke the steam is then fed to a second cylinder to recover the still usable pressure rather than venting to atmosphere. https://www.youtube.com/watch?v=xnClSss50pI
The article specifically states that the original T1 train used poppet valves, not the slide valves commonly seen on steam engines.
@bob Found a couple of videos but none explain how the valve system works. The system is driven by the center of the drive wheels to what appears to be a bevel gear to right angle it to a drive shaft that goes to the pistons (valve bank). You are correct as the video link I posted is for slide valves and not poppets ,but, they are still acomplishing the same goal. In my opine an overcomplicated Rube Goldberg way of making the steam go in and come out. https://www.youtube.com/watch?v=4fELZGD0ED0
P.S. The only steam engines I personally have ever worked on were much smaller slide valves.
Slide valves work well but have high friction losses because they’re sealed by steam pressure pushing the slide valve against the valve face over a wide area of sliding material. Poppet valves were used in later development of steam engines because they have much lower friction, and it’s easy to drive them with a cam, giving you faster opening and closing than a slide valve. (With some effort you can also drive a slide valve with a cam, though.) There are ways to drive rotary/sleeve valves that open/close even faster than a cam-style one, so you have valve timing that more closely approximates optimal.
From what I recall with this project, the cam valves were actually fitted to an original T1 locomotive, so they are still period correct. They were fitted to T1 5500 after it got wrecked, and the valves were supposed to be put on the other T1 locomotives because they worked so well, but the PRR just decided that rather than put more money into these misbehaving steam locomotives they should just scrap them and get higher performance diesels instead, which is exactly what they did.
Also Union Pacific has converted both their 4-6-6-4 challenger 3985 and their 4-8-8-4 big boy 4014 to run on oil, as it is pretty much impossible to handle the logistics of loading coal into the tenders of these locomotives at random locations. It would make a lot of sense for the T1 to be converted to oil so that a truck can just drive up and pump some in instead of a semi (or a coal hopper) and a crane having to set themselves up to load it. I’ve also heard oil burns cleaner in steam engine boilers than coal and requires less maintenance, but I could be wrong about that. I think I heard that in an old UP 3985 documentary.
Coal has a significant amount of fly ash after burning, and is also somewhat of a fire hazard compared to oil. Nowhere near as bad as wood-burning vintage steam engines, but higher than oil.
Additionally to the logistics just getting good clean coal to burn for locomotives nowadays is getting tricky. Most of the coal I’ve encountered intended for power plants is basically unprocessed and of very low quality. It get’s processed and washed at the powerplant, so the mines don’t do anything with it other than break it to the desired size. I’ve encountered stuff like rocks, hammer heads, rags, chisels and boots in power plant grade coal when (after a painful and problematic trip) it was decided to unload the bunkers of a 1930s steam tug of the coal they had received for free and put in better graded polish coal instead. The powerplant coal was problematic in producing lots of ash and slag, clogging the bars and smothering the fire requiring near constant racking and attention to keep steam up.
Fewer and fewer mines are still running and even fewer of those keep their wash plants set up to deliver coal of a grade desired for firing a locomotive as the vast bulk of their output goes to power plants that do their own processing. It’s also getting very very expensive compared to oil firing.
For those of us who enjoy experiencing a coal fired steam locomotive running, I highly encourage you to get your fix in, because it’s quite possible they’ll have to stop running on traditional black coal within the decade as mines close and coal-fired power plants get shuttered further reducing demand for coal in a self re-enforcing increase in coal prices.
If they are going to cheat by making the boiler oil-fired they may as well go the whole hog and make the cylinders diesel!
Long live the Mallard record.
Besides, where in the USA will you find any track that is useable at 140mph with 400-odd tonnes rattling over it?
Hyperloop tunnel? Haha
>> If they are going to cheat by making the boiler oil-fired they may as well go the whole hog and make the cylinders diesel!
Actually, by the end of the steam era oil-fired locomotives were commonplace.
Like fuel choice in industrial applications everywhere, it all depended on what was cheapest and available, and steam locomotives were relatively fuel-agnostic (though it did require design changes). The big railroads that stuck with coal till the bitter end were mostly those like the Norfolk & Western, Pennsylvania RR, and the Reading, where a lot of their traffic was shipping coal to begin with. The fuel was abundant and it made political sense to not antagonize their largest customers, so… coal.
In the west the big railroads had more variables so both coal and many different oil products were used.
Well that all depends on the era in which country.
The UK brought steam back again after the war because we had an abundance of coal and a lack of oil (diesel).
For the vast majority of people, globally, steam power = coal.
And electricity :-)
https://en.wikipedia.org/wiki/Electric-steam_locomotive
Forgot about that one!
There were also propane-burning machines for use in “delicate” areas like industrial settings where cars were shunted in and out of buildings and soot was unwelcome (although some saw mainline service in the American west back in the days when propane and natural gas were low-value byproducts of oil production)
Also, there are steam locomotives that have no boilers at all, they’re just a giant thermos bottle that were refilled with superheated water from a stationary boiler every couple of hours.
https://en.wikipedia.org/wiki/Fireless_locomotive
They were popular in places that needed cleanliness and where a plant source was already available to provide the hot water, think tight warehouse areas or inside mines, where an open boiler fire might be a bad idea.
Like I said in another comment, if you can imagine it, some railroad somewhere has already tried it at least once
Also… oddly enough there were even attempts at what you could describe as “coal burning diesels”, where instead of using the typical diesel engine to spin a generator to turn motors in the wheels, you could use a gas turbine using powdered coal.
https://en.wikipedia.org/wiki/Union_Pacific_GTELs#Experimental_coal-burning_turbine
https://en.wikipedia.org/wiki/Chesapeake_and_Ohio_class_M-1
https://en.wikipedia.org/wiki/Norfolk_and_Western_Railway_2300
Demonstrating once again that if you can imagine it, some railroad somewhere built one and tried it.
Their are power plant turbines the can, theoretically, run on powdered coal. But I don’t think any do. It’s abrasive. It has been tested by the manufacturer.
The Mallard will always be the fastest production steam engine, and also the fastest in-service steam engine. I would hope that Guinness continue to recognize it as such.
The record being chased here is a little hollow. Technically it might end up being the fastest steam engine, but it can’t be proven that the original production models in-service ever achieved that feat. From a hacker viewpoint I totally understand why they are doing it, but from a sentimental old fool viewpoint I’m a little saddened at the prospect.
The Mallard did its speed run under optimized conditions and sustained damage in the process. It may have the current official world record but there is plenty of evidence American locomotives were even faster in regular service and not some one off publicity stunt.
PRR T1s regularly ran a stretch with their 120mph speedos hard against the top pin. Due to unexpected poppet valve issues the PRR started an internal investigation. Said investigation revealed their top speed was over 130mph.
The Milwaukee Road had their 84″ driver 4-4-2 Hiawathas which often ran a long straightaway in Wisconsin at over 120mph. One observer who timed the mileposts with his watch calculated their speed at 125+mph. He asked why the railroad didn’t advertise the speed of its trains and the reply was that some people would be afraid to ride anything that fast.
They have details in this story somewhat croggled.
The locomotive will be designed and built to use solid fuel; it can be adapted to use heavy #5 or #2, or dual-fuel, but it is being restored as a solid-fuel fired locomotive.
And the valves will be rotary-CAM (instead of the original oscillating-cam Franklin System type A) and certainly not “rotary” in the sense of Aspin or similar valves. The modification follows the one T1 that was rebuilt with Franklin’s rotary-cam system — and therein is an interesting story that is relevant here. The RC system was given the name Franklin type B-2, the ‘-2’ denoting that the original eight poppet valves per cylinder (arranged as in the Franklin ‘crest’) were retained and operated in pairs via bridges. This retained the nominal free breathing (as compared to the Franklin type B as seen, for example, on ATSF 3752) while obtaining the benefits… and some of the drawbacks… of continuous-contour shifting cams and spherical followers.
The difference in valve-gear drive is more a matter of substituting a ‘drive arm’ setup for the original heavy frames on some Franklin RC engines or conversions — the arrangement having been pioneered as part of the “Franklin type D” kits applied to Army 2-8-0s, one of which survived and could be used for measured drawings of the arrangement. (Type ‘D’ and its replacement for continuous cutoff control is a whole separate discussion of interest… ;-} )
Record runs will be conducted at the obvious place, the Fast Loop at Pueblo, permission for which use was granted years ago. This is the primary reason for the carefully-instrumented wheelsets that would be used in any real attempt.
Finally, there is little if any reason to retain even Voyce Glaze’s proposed overbalance for the T1 (it is in his balancing book at NWHS) since the likely effect of hunting is vanishingly slight at high-speed cyclic with a locomotive of this length and mass. Any surge could easily be addressed with a Langer balancer if it turns out to be critical in high-speed slipping. With zero overbalance there is far less potential for sustained adhesion upset at high power, even with quartered two-cylinder engines.
Do you have a link to where these details about the valves are? I was going off the information in the linked article, which may have had things lost in translation. It would be great to update this article with the correct information.
I’m guessing Mr Ellsworth’s associated with the project which, I found in the article, is called the “T1 Trust”, with a website here:
https://prrt1steamlocomotivetrust.org
Thanks. Looks like there’s a lot here, but I’ll see what I can find out about the valves.
What really matters is that it can push a DeLorean up to 88MPH!
🤣
blah blah, blah… all the hot air long winded pontificators…..
bottom line 3 words: ship of theseus
Want to make it modern-competitive? Use a Doble generator in there, and put minimalist but functional modern electronics in it.
If you want to reduce co2 emissions then converting it to nuclear is in order.
With all the discussion about making changes in order to use more modern Tech, why not just build an Reactor to heat the water on a continuous basis. Just drive the wheels directly with the shaft of a steam turbine. Maybe it could beat the record by a couple of 100mph. I suggest a 50 to100 mile track built in the desert. Make it a US Gov civil works project.
Yes, you can pull the other leg. Just trying to break the seriousness of the discussion so far!
>> Just drive the wheels directly with the shaft of a steam turbine.
Done. (also by the PRR, btw)
https://en.wikipedia.org/wiki/Pennsylvania_Railroad_S2_class
A lot of what has been said above is missing the point. These guys want a T1. They don’t want something else. To operate a T1 in today’s world, certain modifications are a requirement of accedition & economic realty. No point spending millions on something that can’t run, wouldn’t capture public attention and could not cost recover. That’s the balance. Amazing project with impressive rate of progress!
Ross Bishop. Your answer is probably the most realistic and sensible answer here. It’s a T1 that this team is putting its money and expertise to, nothing else, and modern standards of accreditation will be vital to allow it to run.
The only solution should be that the latest A1 (60163 Tornado) be refitted to A4 specification and allowed to test its actual full speed on the Eurostar line.
Also, I’m not sure how power to weight translates into locomotive speed but using the wikipedia stats for the A1 and the T1 gives 16 hp/t for the A1 vs 20hp/t.
It might come down to the speed capacity of the pistons as their driving wheels are the same size.
I doubt the eurostar line is going to like the dynamic augment and hammer blow that an A4 at full clip puts out. Modern track isn’t really designed or set up to handle those forces well. It should theoretically be able to handle it as far as I can find, but I’m not convinced the owners of that infrastructure would like an A4 to attempt a high speed run on that rail, nor the risk of it breaking down mid-run on their track
While pondering the issue I came across these papers, I’ll share them here for your reading pleasure:
Steam Locomotive Rail Wheel Dynamics Part 1: Precedent Speed of Steam Locomotives
https://static1.squarespace.com/static/55e5ef3fe4b0d3b9ddaa5954/t/55e63647e4b06159647b2fb9/1441150535974/WP_SLRWD_1.pdf
Steam Locomotive Rail Wheel Dynamics Part 2: Mechanical Balancing of Steam Locomotives
https://static1.squarespace.com/static/55e5ef3fe4b0d3b9ddaa5954/t/59baa8dbd55b41bcfdaed406/1505405156607/wp_slrwd_2-1.pdf
Sauce: https://csrail.org/
Rotary cam valves have been successfully installed on atvleastvone restored steam locomotive in the UK, namely Duke of Gloucester 71000. Thiey are driven by a rotating shaft that goes to one of the main crank pins. The technology was around in the 1940’s and is well understood. The group that restored t71000 had to have mostbof thecparts created from scratch as onevof the cylinders had been removed for display in a museum. The locomotive is now a regular performervon thevmain line. During the restoration they discovered that somevparts of the firebox had not been made correctly and the fire couldn’t get enough air. That was corrected and thecperformacecof the loco is now better than when it was in service in the 1950’s. As to the valves, I think that with rotary cams the valves are still poppet valves, like in a car engine. It’s just the operating mechanism that has been modified.
The linked article says they did the work thus far with $1.6 M in donations. That’s the real miracle here. I don’t even know how you would source the raw materials or even pay someone to argue for free raw materials at that rate. Strong work.
I personally think that the A4 speed
Is not only a normal production engine
But people forgetting the main point
It is steam power By coal
If the T1 was to brake the record then it would have to be coal powered
You can produce steam by nuclear fission but using this
Is not the same method as coal
But would produce a much more powerful Locomotive.
Let’s see the response
Any nuclear engineers out there
With a power to weight ratios,
140 tons of engine plus carriages?…..???
the people at Franklin doing valve gear work
so, a T1 being rebuilt aye?, i say go for it, i was never a fan of the PRR Streamliners but this will put steam back on the map