Northwest told of the hyper heisler. Is there a drawing of this locomotive. Gary
I see you've been digging in the archives.
That was proposal that never got drawn out. What it would've looked like was four or six cylinders arranged in the Heisler pattern underneath a larger Mikado-sized boiler. They would transfer power via a driveshaft and geared transmission (for higher speeds) to either 2 or 3 axle trucks, depending on the viablity of the coupling arrangement. (And I suppose that one could use diesel-hydraulic-style methods as well).
Not sure if it was ever practical. Overmod can offer paragraphs and paragraphs of comments if you desire.
NorthWestNot sure if it was ever practical. Overmod can offer paragraphs and paragraphs of comments if you desire.
I actually would say little, other than to review the discussions we had on the subject, which covered most of the issues. Juniatha had a friend who had done detail design on one of these, oil fired with the various mod cons, and that is probably the best example to qualify as an answer here.
I would note that the Lewty booster, perhaps enlarged slightly, comes nicely into an appropriate power (and packaging) range for this sort of purpose, although much of the 'economics' of its use would hinge on widespread prior adoption of the various components for other railroad purposes.
What size drivers would you use and would this locomtive be one unit or two units joined together. Gary
IA and easternWhat size drivers would you use and would this locomotive be one unit or two units joined together.
Drivers would be fairly low, with an understanding that the pinion and ring-gear dimensions in the (sealed) gearcases at the axles might determine the minimum diameter -- probably not less than about 40". There is little point in using higher-diameter wheels UNLESS you use cheek braking (as on some later electrics) where instead of shoes bearing on the treads, and wearing them as well as disrupting free operation of suspension during braking, you have calipers bearing either side of the wheel structure. In that case a larger diameter would be valuable (up to about 58" max, imho) with corresponding adjustment of the final-drive ratio.
The question of 'units' depends on your definition: the basic 'idea' is to retain the single multicylinder engine with what is basically mechanical drive to as many 'multiple axles' as needed to distribute the developed torque. I'd expect a V8 for example to involve multiple trucks, which would likely be handled as in Pacific Coast Shays (permanently articulated units with Cardan shafts between trucks) rather than separable units. I would NOT expect multiple motors rather than a single one under the boiler, nor would I expect one or more boiler/motor units combined in a single locomotive under distributed control (although that could be technically accomplished).
Assume, as with other pure geared locomotives, that careful attention has to be paid to maintenance 'dressing' of wheel diameter and tread profile on a regular basis. There may be some advantage to providing clutches to some of the 'carrying wheels' to allow them to share in initial starting TE but then be disengaged to save issues of differential wear under power at higher speed (where a few trucks could effectively provide the necessary wheelrim torque under proper adhesion)
OvermodThere is little point in using higher-diameter wheels UNLESS you use cheek braking (as on some later electrics) where instead of shoes bearing on the treads, and wearing them as well as disrupting free operation of suspension during braking, you have calipers bearing either side of the wheel structure. In that case a larger diameter would be valuable (up to about 58" max, imho) with corresponding adjustment of the final-drive ratio.
I am not seeing the difference between "old" braking and cheek braking, as far as wheel diameter goes. It appears to me that wheel diameter either matters to both, or to neither.
All else, I do get.
Ed
7j43kI am not seeing the difference between "old" braking and cheek braking, as far as wheel diameter goes.
That's because the wheel diameter relates to the effective TE, not the size of the braking contact area. The situation with high drivers for better speed and balance doesn't apply strictly to geared engines, but the required gear strength (and to an extent the transmission losses) do matter with respect to the implied taller final drive ratio. There are also some implications for stability inherent in higher wheels unless you use truck designs with low effective bolster height.
Part of the issue with cheek brakes on radically smaller wheels has to do with heat dissipation. I do not know whether the brake-disc area can be cost-effectively cast into a one-piece wheel (and one-piece cast wheels are mandatory for much new production). Realistically I'd cast only the mounting points into the wheel, adjusted for expected heat dissipation, and use separate keyed cheek plates (they do not need to run concentrically with the wheel even at high speed, only be balanced overall).
At smaller wheel sizes, the required brake pressure on the smaller swept area might involve 'grabbier' response even as the effective contact-patch size between tread and railhead decreases, making the issue of locked wheels more 'delicate' (and perhaps introducing the need for an antilock system).
There were two locomotive designs that may have fallen into this category, from the 1930s in Britain and in France.
The British design was from Sir Nigel Gresley (before his knighthood) and was a six cylinder geared 4-4-0 based on his three cylinder "hunt" and "Shire" types. This looked like a V-6 arranged below the smokebox with a central drive shaft to the leading coupled axle. Unfortnuately, the decision was taken to use two separate crankshafts geared together (like the big Sulzer locomotive diesels) and a satisfactory gear arrangement was unable to be developed. The locomotivewas completed as a conventional three cylinder locomotive.
The SNCF were working on a tank locomotive which looked like a 4-6-0T with outside frames but since the last axle was not coupled was a 4-4-2T, classified 221TQ-1 if I recall correctly. I think this had a V-6 arrangement (with a single crankshaft) but I don't think it ever ran. It may not have been completed although photos of an apparently complete locomotive exist. It certainly would have been overtaken by the German occupation in 1940 and like a number of such experiments was not revived after the war.
Peter
M636CI think this had a V-6 arrangement (with a single crankshaft)...
Flat six, wasn't it? If a V, then a very shallow V, much like the later Cadillac "V-16" which was nearly horizontally opposed. (I could be misremembering this with reference to the engines that went into the 232.P.1)
French Wikipedia appears to be claiming the engine had 12 cylinders (and Douglas Self says so explicitly), which leads me to wonder if those cylinders were double-acting -- I don't remember them being. They also specifically mention the desmodromic valve gear -- no spring bounce or float. That is an interesting development for DABEG from what I know of their poppet-valve gear earlier.
Apparently this locomotive was started in the mid-Thirties, discontinued in 1938, but apparently taken up again in 1947, to the point we got this:
Outside frame, and the particular point is made that the absence of cranks in the driver axles makes them stronger. Apparently the driveshaft to the final drive was intended to turn 1000rpm at main speed, which would appear to make this steam motor higher-speed than a 567. Cylinders nominal 200mm bore x 280mm stroke, which seems more than a little Paget-ish. I wish we had Claude Bersano back to ask about this. I don't see anything from Thierry on the subject.
That one's interesting. Must have had a mechanical lubrication system, because none of the moving parts are particularly accessible.
NorthWestMust have had a mechanical lubrication system, because none of the moving parts are particularly accessible.
I think this was true for most of the late developed motor locomotives, and I'd argue that some, this one included, would have depended on full-pressure lubrication, as in internal-combustion motors, and not 'shot' lubricators like some of the systems used on many steam locomotives.
There is at least one reference (in the Encyclopedia of World Railway Locomotives) to pressure lubrication of conventional reciprocating-locomotive rod bearings, using hoses and perhaps hard lines on the rods themselves as a return for lubricant delivered under pressure via cross-drilled crankpins and axles. As I recall, this was a Chinese reference, so Peter Clark may have the full technical description and perhaps know of a source for drawings or pictures.
Note that a full-pressure system is probably not a total-loss system (as was typical of most large steam-locomotive lubrication, both liquid and Alemite, and contributed to some of the problems with Bulleid's Leader class valves) and there is a certain amount of care required in assuring that volume, pressure, and temperature of the oil are kept in proper operating range, as is necessary (but often forgotten) in typical road vehicles.
seppburgh2Call it a different type of "hyper heisler."
I'd call them 'hypo-Heislers'
Keep in mind that the original 'hyper-Heisler' discussion had little if anything to do with actual logging locomotives, or conversions of same. It involved an explicitly high-speed locomotive using the same basic idea of cylinders in-V driving a central driveshaft arrangement to gearboxes in the trucks. I suspect the truck arrangement of a Climax (not counting the cockamamie jackshaft setup) would be a better 'design pattern' than the exposed gears in a 'real' Heisler, too.
Overmod M636C I think this had a V-6 arrangement (with a single crankshaft)... Flat six, wasn't it? If a V, then a very shallow V, much like the later Cadillac "V-16" which was nearly horizontally opposed. (I could be misremembering this with reference to the engines that went into the 232.P.1) French Wikipedia appears to be claiming the engine had 12 cylinders (and Douglas Self says so explicitly), which leads me to wonder if those cylinders were double-acting -- I don't remember them being. They also specifically mention the desmodromic valve gear -- no spring bounce or float. That is an interesting development for DABEG from what I know of their poppet-valve gear earlier. Apparently this locomotive was started in the mid-Thirties, discontinued in 1938, but apparently taken up again in 1947, to the point we got this: Outside frame, and the particular point is made that the absence of cranks in the driver axles makes them stronger. Apparently the driveshaft to the final drive was intended to turn 1000rpm at main speed, which would appear to make this steam motor higher-speed than a 567. Cylinders nominal 200mm bore x 280mm stroke, which seems more than a little Paget-ish. I wish we had Claude Bersano back to ask about this. I don't see anything from Thierry on the subject.
M636C I think this had a V-6 arrangement (with a single crankshaft)...
Check out:
Lokomotivbau und Dampftechnik by Wolfgang Stoffels, Birkhauser 1976, pp120-121 and 126 -128.
The cylinders were indeed arranged as a 90 degree V-12 and were both single acting and Uniflow, with trunk type pistons. The final drives were worm drives mounted on quill drives. The locomotive was intended for 145 km/h hauling 480 tonnes in passenger service although there is a reference to hauling 1200t in freight service..
A drawing shows a fully streamlined casing with more rounded water tanks, these features being abandoned when the locomotive was completed post WWII. The details provided by Douglas Self appear correct.
M636CThe final drives were worm drives mounted on quill drives.
This tells me most of what I need to know about why it 'failed to thrive'.
Quill drive will only attenuate so much shock before it 'goes solid' with respect to the thrust bearings and tooth profiles in the worm and its shaft. Probably no backdriving to speak of from the kind of worm pitch that would 'live' with this kind of power transfer, so you'd need to keep enough steam on the motor to ensure the shaft is turning 'faster' than the quill at all times. Probably no cylinder-interruption on the 12 cylinders, too, so watch the water rate balloon "unexpectedly".
Be fun to see the arrangement used to keep water out of the lube oil, mains, and big-end bearings down there at the bottom of a 90-degree V.
Note that this could be treated like three Pritchard V4s in a line for balance, being effectively a 2-stroke so the usual 60-degree V12 angle doesn't apply. Be interesting to see what something like this could do with a better final drive setup!
Probably little better an 'answer to the diesel' than Bulleid's contemporary Leader, though...
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