Why are (and were) there so few 10 coupled steamers in excursion service? The only ones that I know are (were) DM&IR 514 in the 60s, T&P 610 in the 70s, GWR 90 for the Strasburg Railway and Frisco 1630. I guess too slow speed is not an argument because when looking at some videos of T&P 610 in the 70s, you can see that also 10 coupled engines can run pretty fast or let´s say fast enough for excursion service. So what´s the reason why 10 coupled steamers were/are so rarely used in excursion service? I can´t imagine that it´s because they´re not popular...
Thank You.
While some 10 coupled locos like T&P and ATSF had large diameter drivers, many did not, and were considered drag freight engines.
Well, T&P´s 2-10-4´s had small 63" drivers but still capable of easily doing 70 mph, which is pretty fast for small drivered freight steamer I guess.
Bulgaria (in eastern Europe) is in the final stages of restoration to operation of a 2-12-4T, according to a recent British magazine. Even though the driving wheel diameter looks quite small in the pictures, it is still a massive tank engine. Apparently they were developed to move coal trains on grades of nearly 3%.
De Luxe Well, T&P´s 2-10-4´s had small 63" drivers but still capable of easily doing 70 mph, which is pretty fast for small drivered freight steamer I guess.
That would not have been the practise in the 30's and 40's. The general rule for steam locomotives not equipped with roller bearings on the cranks is to restrict them to speeds at or below the number of their driver wheel diameter. For a New York Central 4-6-4, that would have been about 80 mph. For a Pennsy J1 or a C&O H-8 Allegheny, 70 mph and 67 mph respectively. When roller bearings were widely used on fast freight engines or passenger engines, speeds were limited only by lubrication and boiler capacity....and of course local road conditions and limits.
Looking at the requirements for excursion service, there are very few runs and routes that require massive tractive effort and horsepower. For most such, a 2-8-0 or 2-8-2 is adequate - and far less expensive to operate and maintain than anything with ten drivers. Curves are also a problem on most 'tourist' lines.
Excursion operations either have to cover their own costs or have a 'sugar daddy' to make ends meet. The sugar daddies are into the big, flashy (N&W J, UP FEF-3 and articulateds...) power, while frayed shoestring operations have to mind the bottom line. Ten-coupled locos, in most cases, fall in the vacant space between the extremes.
Chuck
There are several reasons why 10-coupled steamers are rare in excursion service. One big reason is that there just aren't very many still in existence compared to other types. Steamlocomotive.com lists just eight 2-10-4 Texas types that have been preserved, compared to thirty-eight Northern types in North America. There are some 2-10-2 and 2-10-0's preserved as well, but those are older designs dating to the teens and twenties, and generally lack features like roller bearings and cast locomotive frames that make maintenance easier. Most, if not all, 2-10-2's and 2-10-0's also have 63" or smaller drivers, which limits their speed. Some may point out that older 2-8-0's and 2-8-2's in excursion service also lack roller bearings , cast frames, and tall drivers and that is true, however for operations where it only makes sense to run small to medium size locomotives, the options are usually limited to older equipment from the first two decades of the 20th century. Operators needing bigger power have more choices, including 4-8-4's which, I would argue, offer a better tradeoff between tractive effort, speed, and ease of maintenance. While a big 2-10-4 or 2-10-2 will probably have more low speed tractive effort than a typical 4-8-4, most Northerns have plenty of grunt to haul the average excursion train, and are able to maintain much higher track speeds where allowed.
I was waiting for someone to point out the three Chinese QJ-class 2-10-2's (built in the 1980's!) that have run on the Iowa Interstate (2) and RJ Corman railroad in the past few years. They are on the small side, but seem to be popular nonetheless.
Personally, I'd love to see the Susquehanna recover a 2-10-0 "Russian" Decapod (there are still some out there) and restore it for limited excursion service, the "Suzie-Q" was famous for it's Decapod usage, but I'm a realist, it ain't gonna happen. Present Suquehanna management wants nothing to do with excursions, steam excursions died with Walter Rich, God rest his soul!
Hey, it's their 'road, they call the shots, I'm just a railfan, they've got no reason to keep me entertained.
Firelock76 Hey, it's their 'road, they call the shots, I'm just a railfan, they've got no reason to keep me entertained.
This is a point that we all need to remember.
As far as I know SF #5021 is in the process of restoration. Once this monster is finished, it will for sure be a sensation. Strong and fast because of it´s 74" drivers...
I am surprised that no one has mentioned the Iowa Interstate's TWO QJ's, or even R.J. Corman's 'QJ' (2-10-2s)
Admittedly, they are oddities, but they are still very viable steam engines, even though they have not been recorded as having been out on 'The Line' recently.
Here is a video of R.J. Corman's engine: @ https://video.search.yahoo.com/video/play;_ylt=A2KLqICui4hVkkMAPbMsnIlQ;_ylu=X3oDMTByMjBzZmhtBHNlYwNzcgRzbGsDdmlkBHZ0aWQDBGdwb3MDNg--?p=Chinese+St
and these @ https://video.search.yahoo.com/video/play;_ylt=A2KLqICui4hVkkMAOLMsnIlQ;_ylu=X3oDMTByZWc0dGJtBHNlYwNzcgRzbGsDdmlkBHZ0aWQDBGdwb3MDMQ--?p=Chinese+Steam+Engines+In+America&vid=ef5caf5c9372bb4f703d618b6c127f09&turl=http%3A%2F%2Fts4.mm.bing.net%2Fth%3Fid%3DWN.n1RWgUOVUZnS8fBk0QFu5Q%26pid%3D15.1%26h%3D168%26w%3D300%26c%3D7%26rs%3D1&rurl=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DiDCL8hHDgpE&tit=Train+Festival+2011+Chinese+and+American+Steam+locomotives&c=0&h=168&w=300&l=63&sigr=11b0is65q&sigt=11qn66ubq&sigi=12kd3l36v&age=1316654868&fr2=p%3As%2Cv%3Av&fr=yhs-mozilla-003&hsimp=yhs-003&hspart=mozilla&tt=b
I see many references to driver diameter and speed but none mentioning the other factor in the equation: counterbalancing. Sure an engine may be able to get up to 70MPH on 63 inch drivers,but at what cost to the locomotive itself, as well as to the track? Most 10 coupled freight locomotives were counter balanced for 40-50MPH maximum speeds, and to push one beyond that will cause a fabricated frame to begin to disassemble itself as each revolution of the drivers hammer new kinks into the rails. Pennsy I-1 Decapods come to mind as some rough riders at speeds above 35-40MPH.
NHTXI see many references to driver diameter and speed but none mentioning the other factor in the equation: counterbalancing. Sure an engine may be able to get up to 70MPH on 63 inch drivers,but at what cost to the locomotive itself, as well as to the track? Most 10 coupled freight locomotives were counter balanced for 40-50MPH maximum speeds, and to push one beyond that will cause a fabricated frame to begin to disassemble itself as each revolution of the drivers hammer new kinks into the rails. Pennsy I-1 Decapods come to mind as some rough riders at speeds above 35-40MPH.
Best place to start is likely the Trains article about dynamometer testing T&P 610, which goes into many of the relevant features of the circa 1938 rebuilding that turned this locomotive from a drag-freight dog to a locomotive able to run easily at higher speeds. Follow that up if you like with the CSR presentation on balancing (I think it's 'part 2' of something with a not-too-well-associated name), which covers some of the other fine points involved in the various factors.
Note that a 10-coupled engine driving on the 'middle' driver pair is imposing the yaw force from 'low overbalance' at just about the least ideal place geometrically: right at or close to the yaw center. On the other hand, the polar moment of inertia resisting the momentary perturbing force is maximized, and of course as speed increases, the forces alternate quicker and quicker meaning that the time for acceleration is less even as the effective force per alternation may be changing. With the long wheelbase and mass of a 'modern' ten-coupled engine, I would expect this to be minimal, perhaps even tolerable up to necessary excursion speed even with 'zero overbalance'.
This leaves surge as the other concern if overbalance is minimized. Langer had a patent in the late '40s that addressed this with a gear and counterweight arrangement, which looks a bit Mickey Mouse until you realize what it is for.
With zero overbalance (or Voyce Glaze's approach to low overbalance on the main, which puts only enough there to counteract the vertical component of piston thrust) you have neither severe augment nor severe hammer blow up to a much higher rotational speed than 'typical'. In Australia it was apparently a success to use zero overbalance on an elderly class of 4-6-0, which i would not have expected; it should be even more feasible on large American power being driven as conservatively as 'preservation' engines probably should be. It would certainly keep vertical perturbing forces 'in line' with what nose-suspended traction motors on diesel-electrics do to track.
63" drivers turn out to be high enough for relatively good speed if proper lightweight rodwork and good balancing implementation are provided. Keep in mind that "70 mph" may be a maximum speed, at which some unbalance forces are clearly present Ias in some reports regarding NKP Berkshires, IIRC) rather than maximum service speed. A more critical measure is the rotational speed at which 'normal' vertical augment just equals adhesive weight on the affected axle; think of this as the V-sub-NE of a reciprocating steam locomotive.
An interesting topic that has just come up on the PRR Yahoo group is that the PRR J class locomotives, which were built with 69" drivers following an AMC design, were listed with 70" drivers from about 1948 on. There had to be good and adequate reason for PRR to make that change, and I suspect it is a combination of the good inherent design of the locomotive and the need to retain the as-designed rodwork and valve gear... but it does raise the issue that on a railroad with a nominally-strict 50 mph speed limit, 70" was 'better' enough than 69' to make the change.
BTW, the PRR Decapods are an interesting case -- an obviously drag-freight engine that could easily reach speeds of 50 mph or better, although of course the ride at such speeds starts to beggar description. If I rmember correctly, it's not so much 'balancing' as characteristics of the wheel arrangement and suspension that cause the hard riding; a better connection between engine and tender might go a long way to ameliorating that (although PRR would probably have seen little or no need to do an expensive refitting during the period that advanced balancing was being practiced in this country!)
@ Wizlish: excellent post and very interesting info! It shows that a lot of things can be possible when you just know how to improve it in the right way. T&P would have certainly not used their Texans on their flagship train (Sunshine Special) if these engines were not suited for that task. Just proves that a 2-10-4 really knows how to "stretch her legs" even with 63" drivers. Very interesting info about the PRR Texans! Never knew the drivers were enlarged by 1" in 1948! It´s indeed confusing considering the 50 mph speed limit! I can understand that none of their unsuccessfull and complicated-to-maintain duplex designs were preserved, but at least PRR could have saved a Texas from the scrappers torch. Just imagine a J1 storming through Horseshoe Curve with a 25 car excursion train...
I will guess -- guess -- that the need for two crews made for managment headaches that were tolerable for original road service but intolerable for a tourist railway.
Actually, I can think of several more 10 coupled locomotives that ran on at least one excursion. Someone else mentioned the two Iowa Interstate Chinese 2-10-2s. R.J. Corman also has a Chinese 2-10-2 that has pulled excurions, I believe. Back in the late 1950s, Colorado & Southern operated at least two of their 2-10-2s on excursions. I think that SP 4-10-2 no. 5021 at Los Angeles Fairgrounds, may have operated on at least one excursion. Finally, my favorite, in Sept, 1959, the CB&Q operated 4-8-4 no. 5632 doubleheaded with M-4 2-10-4 No. 6315 on an excursion which didn't end well. West of Mendota, IL, the big 2-10-4 damaged an eccentic rod and was pushed by no. 5632 into Galesburg, never to run again. However, while it was operating, it was a spectacular show. Glad that I was there to witness it!
Does #90, the Strasburg Railroad's Decapod count? I've ridden behind that one, however is doesn't go off the SRR's nine miles of track.
It is a gorgeous piece of machinery, though!
Hey, I just thought of something. The Germans run Type 44 and Type 50 Decapods in excursion service, der old Kriegslokomotiven, do they count, or are we just concerned with American ten-coupled locomotives?
Firelock76Hey, I just thought of something. The Germans run Type 44 and Type 50 Decapods in excursion service, der old Kriegslokomotiven, do they count, or are we just concerned with American ten-coupled locomotives?
While you are at it, why not mention the most modern of road steam locomotives, the 8055, which IIRC is based on a Kriegslok.
I don't think, though, that most of the services ('Plandampf' etc.) actually require a 10-drivered locomotive, or that an eight-drivered engine couldn't have been a 'better' starting place to develop a modern engine for the expected level of work. Same with Strasburg: there are plenty of 'candidates' that would do the things they do "better" than a Dec... but that is what they have, and a good thing too!
Don't forget British Rail's 9F class of 2-10-0's, the last steam locomotives built in Great Britain.
ndbprrNobody is and should not run a steam engine or any other relic at its top design speed. Ever see a model. T on the interstate doing 70mph? There isn't a steam engine in service that isn't at least 60 years old. I can only imagine what liability insurance would cost if you could get it. I doubt running one at that speed would make more then one trip and would be unserviceable at the end if it was still upright.
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