Currently the British National Railway museum is planing to celebrate the 75 anniversary of London & Northeastern A4 pacific #4468 "Mallard's" speed record of 126 miles per hour. That got me wondering if there are any preserved steam locomotives left that are capable of breaking that record. I understand there are other, operable A4s. I would also think C&0 614, Union Pacific 844, N&W 611 and SP 4449 would all be possible contenders given the right conditions. What do you guys think?
Modeling the Pennsylvania Railroad in N Scale.
www.prr-nscale.blogspot.com
AFAIK, there are 3 A4´s in working order in Britain, but as they are considered a national heritage, I doubt that anyone would want them to go 126 mph. In Germany, Deutsche Reichsbahn class 18 201 has a top speed of about 115mph and could achieve probably more, but is limited to 100 mph in today´s use.
UP 844 was designed to do 100 mph, but I think she´s good for more.
I wouldn't want to be anywhere near the mudchicken if such a record was attempted on HIS tracks.
Of the group I think that 611 would have the best chance. N&W designed and built the Js such that they were balanced for 137mph. And on the eastern end of the line they would regularly hit high speeds of 100 and more.
I recall as a child that a neighbor who was an N&W engineer talking with Dad about how the Js would cruise at 100mph as smoothly as a car at 60. And he said they could sprint much faster than 100 if he had the courage.
I do recall that travelling along US-460 that on an open section of highway paralleling the track we could not keep up with the N&W's passenger trains. And Dad was a real leadfoot.
Most of the above mentioned engines were balanced for speeds in excess of 100 mph. How many engines ever hit that speed? I would not want to be on a N&W J running at over 100 mph with those small 70" drivers and rods thrashing away. The above engines are all capable of 'cruising. at 70+ mph - the limits would be curves, and the need for fuel/water.
IIRC, the Milwaukee A class engines did hit 112 mph in tests pulling Hiawatha consists. 100 mph running was done on the C&M division and across parts of central Wisconsin. The reality was around 65-67 mph average speeds on the Chicago - Twin Cities assignments. The key is a good level track with no curves, and the ability to keep steam pressure up as it is being used at rather high rates of consumption.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
If I could be sure the tracks were rated accordingly, I would attempt it in a Pennsy T1 4-4-4-4 or a NYC S1b Niagara. I would trail no more than 400 tons and start on a 1% down-grade, or run it up to speed on one, and see how it maintained on level track.
Could it be done with any of the aforementioned American 4-8-4's? Probably, especially N&W's 611, but it probably wouldn't be a good idea considering they're all one of a kind priceless artifacts. If you "break" one how do you replace it? As cool as the attempt would be it would be kind of reckless to try. Fun to speculate on, though.
It could certainly be done with a T1 Duplex. A 1991 anecdotal narrative in Trains mag describes a run in a soon-to-be-scrapped T1 where the train got behind by the time the T1 took over the consist. The crew were a bit dismayed because they had anticipated a run in a nice new, clean, F unit, and dressed accordingly, but the dispatcher told them they had to use a dusty, dirty, T1 that was just finishing hostling. It didn't have the shroud between the tender and cab, and the interior was filthy, it having sat for many weeks unused. Near their destination, on the longest pull of the day, about 40 miles, they made up about nine (9) minutes on the schedule. A little math will tell you how fast they had to move in order to achieve that recovery at what ought to have been 79 mph top speed, and accelerating and decelerating to limits at each end of that leg.
Crandell
NB - I am not positive about all the figures, but what I post is close enough for discusson purposes.
I would be cool if Mallard could break its own record. But as mentioned above, Mallard and the other remaining A4 Pacifics are national treasures and probably not worth the risk. Also Mallard is not operational from what I understand. I know restoring a steamer to operation on this side of the pond is no easy task but I have no idea if England is as strict as the FRA. Does the UK have an equivalent of the FRA 1472-Day inspection?
Hi everyone
The N&W J class 4-8-4 was a valiant and versatile type of locomotive - they certainly performed everything expected from them and then some - yet to expect to top the already incredible feat of running one of these very powerful and heavy locomotives at metric diameter speed ( 177 km/h on 1778 mm wheels ) would simply mean to ask the unreasonable - mind the enormous increase in mass inertia with any further increase in rotaional speeds !
As for the LNER A4 Mallard , the record may be considered a somewhat overly ambitious effort since it was down-hill and the engine was actually driven recklessly without regards to mechanical limits - resulting in its immediate self-destructing , Mallard could not continue the trip , the inner drive having yielded to excessive mass forces .
I would consider it a sine qua non for a successful run , it has been made on locomotive performance only , i e without help of gravitational force and the engine finishes high speed section in good mechanical condition , remaining fully serviceable and able to finish the trip without trouble , actually able to repeat the effort .
That condition was met by the 200.4 km/h run of DR 05002 , 124.4 mph .
As for 18201 , this one-off engine was a rebuilt , composed of Reko 39E boiler as used in 03-10 Pacifics put on chassis and drive of former 61002 tender locomotive of but 390 mm cylinders diameter - then replaced by 520 mm cylinders from 45024 to act on unchanged drive and pins - not a combination supporting very high rpm running . It is said on a test run on the Velim circle of CSD the engine experienced alarming vibrations while attempting to accelerate beyond some 185 km/h or 115 mph and the effort was consequently called off . On the 1987 Vienna steam weeks the engine featured a 100 mph run with six coaches between Glognitz - Vienna Neustadt which was a resounding success engine wise and with the crowd . 160 km/h or 100 mph are very much considered a practical speed limit for this engine and even that never seems to have been tested since - understandably , because the Pacific with her rare 7'7" drive wheels is a mayor asset to german steam heritage .
Remain the Chapelon Pacifics which also were rebuilts from what actually were among the first designs of Pacifics in France , in other words mechanically quite dated when in the 1950s two of these engines were called to perform high speed runs for testing pantographs design and behaviour at high speeds . In the wake of these runs with loads consisting of a short test train plus idling electic locomotive - presenting a considerably higher running resistance than same mass in coaches - the engines reached 174 and 175 km/h or 108 and 109 mph - very respectable speeds for these relatively old engines of delicate mechanical design . Had one of Chapelon's proposals of 4-6-4 locomotives been realized , bettering 200 km/h or 125 mph would have been no question since power output , free steam flow , mechanical sturdiness and vehicle comporting would all have been supportive of high speeds , likely reaching some 220 km/h or 137 mph , say 140 mph .
One more word on the german 05002 : I feel like the effort had been called off prematurely , the train was still in acceleration and knowing prevailing conservativism of german approach in railroading I wonder if the engine ever had been fully extended the way we would call full cry in America . More likely , the train riding VIPs exclaimed "Enough !" once the dyno car's speedometer had just passed the 200 mark . If continued at full output on the level stretch it was riding the engine might have levelled off around some 210 km/h or 130 mph ...
We'll never know - or does someone have the money to get 05002 or other vintage steam out of the Museum , have her fully overhauled and then convince a railway to allow for another try ?
I guess not - rather let's spend that money on exploring Mars ...
As concerns the various American 4-8-4s I'd consider the Niagara type best suited for reaching exceptionally high speeds , above that reached by UP 800 class or any other 4-8-4 - simply because the Niagara had the machine configuration best suited for highest rpm running of all 79 - 80 ins drivered 4-8-4s : a relatively small cylinder volume of decent piston thrust , comparatively free steam flow through cylinders combined with top boiler steaming capacity and well executed vehicle guiding devices . Equipped with tandem rod system , a Niagara may have been able to reach and surpass 530 rpm or metic diameter speed .
As concerns the T1 Duplex , the class , having four smaller cylinders and lighter rods , lighter hammer blow effects , should have been a natural winner over Northerns as concerns speed or , precisely : rotational speed . Yet , I'm afraid the oscillating poppet valve gear was not up to demands of such very high mechanical stresses as with mass forces around 500 rpm or over . I have come to think it would have went self-destructing at around some 450 .. 470 rpm , i e 100 - 110 mph would be a limit as by mechanical integrity of drive - not regarding vehicle comporting on track at such speeds . ( I consider all stories of 'run down T1 living up to a final flight at 115 mph or better' to be myths - just consider the wanting condition of tracks on Pennsy main lines in 1945 - 49 , 'bumpy' riding at but some 80 mph even shown on a Pennsy advertising film - if they had considered the bumps off regular they'd have cut it out , but they didn't : bumpy rides must have been considered normal at those speeds - therefore no permanent way for 120 mph flights of such a massive locomotive !)
Regards
Juniatha
Hi Juniatha! And everyone else, so don't feel left out. Now I don't know WHY this slipped my mind but several years ago I met a gent who served as a crewman on N&W's Class J during the N-S steam program years. He'd met quite a few N&W veterans, both enginemen and design team members who told him that theoretically, that's THEORETICALLY mind you, the J's were designed and balanced for a projected top speed of 130 miles-per-hour. Of course there's no way the N&W would have run them that fast, there wasn't any need to, and few opportunities to, but the capability was there.
As it was, one N&W engineer ran a J up to 115 miles-per-hour on the "Racetrack" between Petersburg and Norfolk. He didn't keep it at that speed for long, but the locomotive did it and suffered no ill-effects. The plain fact of the matter is N&W never did find out how fast a J would go.
And Juniatha, I've seen that old Pennsy promo film too. Watching the engine crew going bump-sway-bump-jump-thump makes me wonder just what the track conditions were like as well. Or maybe the Pennsys engines were just rough riders? Makes you wonder...
By the way, some old-timers here in Richmond told me Route 460 which parallels the "Racetrack" was a great place to go train watching and chasing back in the N&W steam days. A great place to get speeding tickets too if you let your enthusiasm get the better of you! It's STILL "Speed Trap Central" down that way!
selector It could certainly be done with a T1 Duplex. A 1991 anecdotal narrative in Trains mag describes a run in a soon-to-be-scrapped T1 where the train got behind by the time the T1 took over the consist. The crew were a bit dismayed because they had anticipated a run in a nice new, clean, F unit, and dressed accordingly, but the dispatcher told them they had to use a dusty, dirty, T1 that was just finishing hostling. It didn't have the shroud between the tender and cab, and the interior was filthy, it having sat for many weeks unused. Near their destination, on the longest pull of the day, about 40 miles, they made up about nine (9) minutes on the schedule. A little math will tell you how fast they had to move in order to achieve that recovery at what ought to have been 79 mph top speed, and accelerating and decelerating to limits at each end of that leg. Crandell NB - I am not positive about all the figures, but what I post is close enough for discusson purposes.
I remember that story. They related that they had pegged the speed recorder/indicator, though I don't recall what speed that was. The implication was that they were well north of 100, probably in the 120s somewhere. I also recall them being called on the carpet after their run, but with a bit of a wink....
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Hi all PRR T1 the fastest steam loco type of all ?Might have been in theory , yet in practice I rather think not . The valve gear - basically a miniaturized in-between frames version of the Walschaerts , actuating cam rocking camshafts actating valves - was too delicate to stand a 530 rpm plus rotational speed necessary to run metric driver dia speed ( i.e. 203 km/h with 2,03 m diameter wheels / 126 mph with 80 ins ) Having seen drawings of it , I would estimate this valve gear design would become self-destucting around or above some 440 - 450 rpm . This , plus the simple design of plain round nozzles / cylindrical chimney double stack draughting causing severe back pressure and having to do so in order to function just sufficiently , leave alone adequately , forget anywhere near brilliantly , plus the fact peak cylinder output on the loco test plant ( at optimum working conditions , that is ! ) had been registered clearly below 100 mph - not to forget absence of any length of track on Pennsy lines west just plain acceptable for speeds in excess of 100 mph ( some rides shown on PRR's own public relation films are dubious enough at some 80 mph , yet that was on track cleared for 100 mph ! ) all make me sceptic about claims like 110 .. 115 mph , scepticism increasing by rate of 5 % per each mph claimed above 100 mph . If at all , I would rather see ( or hope to see ) some degree of realistic chance for the S1 6-4-4-6 having surpassed 126 mph - yet , again , where was the section of straight line with track and embankment aligned to suiting precission and when should it have happened ? - unlikely after 1945 , unlikely during the war . Further , stories of the kind "this was the last run and they wanted to see what she could really do" simply ignore the fact such run-down steam locomotives facing end of life to meet the reaper's torches were badly lacking mechanical-technical condition needed to put up any extraordinary effort , more likely they barely had capacity to get the job done if by a narrow margin and with toils and tears - neither steaming nor cylinder steam heat to power conversion nor mechanical transmission into turning moment nor vehicle tracking steadiness were likely above a minimum needed - in simple words : a former race horse now a dobbin barely alive could not be expected to break any records . To my thinking , off-hands I'd consider the CMStP&P F-7 or NYC J-3a Hudsons first candidates for fastest US steam as concerns speeds attained in actual traffic - if only at occasions where scheduled speeds had been surpassed . The Milwaukee 4-6-4 and 4-4-2 did attain or surpass 100 mph plus speeds on a regular basis and in view of miles in regular service passed at speeds in excess of 100 mph sure have been the fastest steam locomotives in the world .
Regards Juniatha
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