daveklepper The cutoff could have been controlled electrically from a speedometer.
The cutoff could have been controlled electrically from a speedometer.
It could. That is not much more complicated than the system used for reversing the Algerian Garratts with Cossart OC-and-drop-valve gear. On the other hand, why go to all the trouble of assuring control and power circuits on the locomotive, worry about what happens if the motor controlling the reverser goes out, etc.
As another hint: the only cab control was a switch from forward to reverse. I had thought there would be a lockable neutral position, but apparently there is not. All the work is done using brake air, and the control valves are standard items as found in automobile lifts (!!). There is no modulation in the control at all -- it is full forward, or full reverse, and (hint) there is no mechanical linkage at all controlling the cutoff functionality.
OK, but there is a way of mechanically accomplishing the same thing, the way a mechanical speed governor works. Off one of the axles is geared a spinning horizontal pair of wheel, stacked vertically, with four springs connecting their rims. Half-way up each spring is a weight. The faster the wheels sping, the further out the weights make their orbit because of cetripacle force. In thd center of the top wheel is an air injection nozle and at the perifery an exhaust opening, the whole thing arranged so that the rotating weights effectively act as a throttle on the air-stream from the injector to the exhaust . There may be other possibilities for pure mechanical, non-electrical, speed control of device, but that is one.
daveklepperOK, but there is a way of mechanically accomplishing the same thing, the way a mechanical speed governor works.
This is true... but how more elegant would it be to allow the characteristics of the steam to do the cutoff automatically That is what this system does. There is no governor, no fiddly little bits and springs (as with Corliss valves) to get deranged or shot away. Just a forward and reverse air servo...
... the heart of the innovation being how the cutoff effect is done, effectively, without explicit mechanical control -- feedback or otherwise --
Another hint: there are cams involved. Of a very particular profile.
I am wondering if the Venturi effect played a role in this system but that's just a SWAG on my part. The steam pressure at the constricted section of the Venturi would vary as the volume of steam admitted by the throttle is increased or decreased. This pressure variance might be used to rotate a spring loaded cam which in turn would vary the cutoff.
Mark
KCSfan I am wondering if the Venturi effect played a role in this system but that's just a SWAG on my part. The steam pressure at the constricted section of the Venturi would vary as the volume of steam admitted by the throttle is increased or decreased. This pressure variance might be used to rotate a spring loaded cam which in turn would vary the cutoff. Mark
The system that worked so well in the immediate post-WW1 period was simpler; it measured back pressure and tinkered with a more-or-less conventional reverser to get simple homeostatic feedback control.
The system in question is not using steam pressure as a control of anything. It wire-draws the admitted steam for a longer period, thereby simulating the mass-flow difference that a radial valve gear produces as it it hooked up.
Yes, it's an approximation, and yes, I don't think I'd expect it to work at high speeds... with just the simple cam profiles used. You would need more profiles ... or a variable contour ... to get a closer approximation.
Is everyone having fun yet?
Well, so far KCFan came a lot closer than I did!!
Was the cam (or cams) mounted directly on one of the wheel axels or on a separate cam shaft perhaps driven by a gear mounted on one of the axels?
KCSfanWas the cam (or cams) mounted directly on one of the wheel axels or on a separate cam shaft perhaps driven by a gear mounted on one of the axels?
That would give it away. (This comment itself gives it away...)
The locomotive that got the test improvement still exists today. With the improvement still installed.
“By George, there still exists a steam locomotive from the Ma & Pa. (Albeit the markings say USA.) The Baldwin Locomotive Works, 2-8-0, serial number 69856, is stored by the Texas State Railroad in Rusk, TX. This locomotive was built in August, 1943 and was donated by the U.S. Army to Texas in 1971. U.S. Army engine #611, number 2628 prior to 1952, has a Ma & Pa history.”
Forgotten Ma & Pa Steam by Alan Frame
http://www.susquehannanmra.org/newsletters/ss1099.pdf
http://www.railpictures.net/viewphoto.php?id=354250
wanswheel“By George, there still exists a steam locomotive from the Ma & Pa. (Albeit the markings say USA.) The Baldwin Locomotive Works, 2-8-0, serial number 69856, is stored by the Texas State Railroad in Rusk, TX. This locomotive was built in August, 1943 and was donated by the U.S. Army to Texas in 1971. U.S. Army engine #611, number 2628 prior to 1952, has a Ma & Pa history.”
And, indeed, it does have a Ma and Pa history -- and why it was tested there has a bearing on our story here. Why was USATC 2628 special?
And it isn't in Texas any more. It went to Tennessee long ago, and is now in Maryland.
Well, it was unique. The only one of thousands built to sound like Casey Jones drove it.
Excerpts from Lineside Legacy article by Jeff Terry
“During World War II, the U.S. Army contracted with the three major locomotive builders (American, Baldwin and Lima) to build the largest batch of identical steam locomotives in the United States, the U.S. Army Transportation Corps (USATC) class S-160 2-8-0s. Between 1942 and 1945, some 2120 of these identical “G.I” Consolidations were mass-produced and shipped across the globe to be used in all manner of freight and passenger service within the war-torn allied countries where motive power shortages had crippled the railroads...
“Over the years the [714th Railway Operating] Battalion upgraded the S-160s assigned to Fort Eustis with cross-compound air compressors, pilots, electric headlights, power reverse gear and other refinements. One, No. 611 (built by Baldwin in 1943 as USATC No. 2628) was fitted with Franklin rotary cam poppet valve gear and tested in regular service on the Maryland & Pennsylvania in the early 1950s. No. 611 was also notable for its whistle — an exact replica of Casey Jones's homemade "whippoorwill," built specifically for the engine by a railway battalion sergeant.”
http://www.maparailroadhist.org/histimg/usarmy2628.jpg
All good -- and you're 95% of the way there. But there was something special about this particular Franklin poppet valve gear that is at the heart of this question.
The Vulcan installed rotary cam poppet valve system on No.611 was tested on the Ma & Pa in 1950.
98 percent of the way there -- but still no cigar.
Vulcan built the setup as a 'kit' -- probably thinking there would be repeat orders. It's easy to think that the MRS-1 and subsequent diesel progress made this idea obsolete... but remember, this was very soon after the lessons of the Panzers and the pitfalls of dependence on gasoline and diesel fuel for mobility in wartime. Steam runs on almost any fuel and can use many available sources of water in a pinch...
1) What was special about the setup Vulcan provided? (Extra points if you can cite the specific patent involved.)
2) Why was testing on the Ma and Pa valuable if the valve gear setup was made in Wilkes-Barre? (Note that the answer is really only six letters long ;-} )
The rotary cam setup is used to facilitate the automatic cutoff -- but it is NOT done by shifting the cams, as in Franklin type B or Long Compression. What is done instead? (Interestingly enough, the patent for the Long Compression (which I call stillborn type C) was issued AFTER the patent for the setup used on 2628/611...)
Several patents by Julius J. Kirchhof (1904-1974), photographed in 1962 as president of Franklin Balmar. Was his location convenient to Ma & Pa tracks?
http://www.google.com/patents/US2518024
https://www.google.com/search?tbo=p&tbm=pts&hl=en&q=ininventor:%22Julius+Kirchhof%22
“Balmar was the engineering and manufacturing side of Franklin Railway Supply Co., which in turn was a subsidiary of Lima Locomotive…a young engineer named Julius Kirchhof, formerly with the Debeg Co. of France…brought to us a lot of European know-how and much personal expertise in the design and construction of cam-driven poppet valves.” (Railroad Magazine)
Here’s something else to see: No. 612 at Fort Eustis in the 1960s
http://www.youtube.com/watch?v=clnh9aV2Jiw
Well, my hat's off to you; you've answered with 108% of the material ... and still not gotten the question.
You even have the right patent search.
Yes, the six-letter word is "Balmar" -- Franklin wanted their new baby close by to keep an eye on things. The locomotive is said to have worked so well on the Ma and Pa that they wouldn't give her back, and the Army had to threaten some dire consequence or other.
Now I know something about how Dave felt with the postwar-coach thread! Won't somebody PLEASE answer about what 2628611 does to control her cutoff automatically?
Well.suppose the cam opens and closes a valve. And that valve admits control steam either from where it exhausts from the cylinders into the smokebox or from just before supply steam enters the piston vavles. In either case, the steam pressure should be related to throttle setting, and in the first case it will also be somewhat related to load, inversely. Now one variation is that the cam opens the valve, but it closes because of spring and wieght action after a very short predetermine time, regardless of how often it opens. Put this all together in whatever combination you want and you should have some way of relating cut-off to what the locomotive requires for good, if not optimum, performance.
If this is part of the correct answer, stillm W and KC gave a much greater part of the answer.
daveklepper Well.suppose the cam opens and closes a valve. And that valve admits control steam either from where it exhausts from the cylinders into the smokebox or from just before supply steam enters the piston vavles. In either case, the steam pressure should be related to throttle setting, and in the first case it will also be somewhat related to load, inversely. Now one variation is that the cam opens the valve, but it closes because of spring and wieght action after a very short predetermine time, regardless of how often it opens. Put this all together in whatever combination you want and you should have some way of relating cut-off to what the locomotive requires for good, if not optimum, performance. If this is part of the correct answer, stillm W and KC gave a much greater part of the answer.
Dave, that's a thoughtful answer, and I believe Ross Winans used that approach on some of his prewar power (that's pre-Civil War). Of course the Corliss gear can be made to do something like this.
I trust you don't mean 'control steam' to work a conventional reverser mechanism. All that's necessary to do that is a back-pressure control signal with a certain amount of filtering (via dashpot) to take out any high-frequency oscillations that the reverser might try to follow. I suspect that if ATC had actually been developed as a mandate in the '20s this system would have come into much more widespread use, as it inherently provided a means to center the reverser in a penalty-brake situation...
But the solution used for 'cutoff control' on USATC 2628/611is MUCH simpler, as well as being a bit better dynamically. If you follow the link previously given you will come to the explanation. As another hintlet, I think this system was implicitly being used on the Steins locomotive (patent 2,586,109) -- see the cylinder blocks?
I am not sure how to apportion credit or blame here. Obviously there is some bravura data mining going on here. On the other hand, interpreting the data seems to be missing (as is detection of some fairly obvious technical stuff on the Web, including a discussion of the details of the system itself (albeit in a somewhat unlikely place to find such a discussion). With all the work that has been done on this thread, I expect to see a certain letter of the alphabet used to describe this system accurately, too.
Except that COMPRESSED AIR is used as the control mechanicsm and not steam, the system appears to me to work pretty much as I described. The cam operated valve gear has several profiles on the cams, and which profile ends up moving the valves is determined by how long air-pressure control is applied to the cam mechanism for each half revolution of the drivers (since there is a spring return to zero when air pressure is removed). That to me is the simple explanaition of how the gadget works, although its application and design seems very complicated --- but not really any more complicated than a regular Walchearts or Baker valvegear.
We are still waiting for a KCS question on the thread with the coach interiors, so the choice is between W and me, and I'll be glad to defer to W if he has a question ready.
Except that isn't how it works at all. You are basically describing Franklin type B (or type C) which shifts the cam profiles to match the speed (more or less continuously in the continuous-cam version of type B and the Long Compression setup -- which had its own problems with line-contact wear, but that's another story).
All the compressed air on 2628/611 does is move the camshaft (as in Franklin type B) so that either the forward or reverse cam is engaged. (If I recall correctly there is a center cam for 'neutral' that holds the exhaust valves open but I'd have to look at my notes to be sure about this). There is nothing but mechanical following of the cam surface, and no fancy pulloffs or trips in the follower mechanism a la Corliss. The cam appears to be 'locked' in position (the actuating lever returns to the full upright position after the direction has been selected).
So you still have not realized the principle that is used to regulate 'cutoff' with increasing speed.
Keep trying; I'm sure you'll get it... if you are looking at the right patent. And I'm still waiting for the letter in question... quick! before W gets it in a brute force search!
I read the correct patent, but the figures don't show up very clearly, and obviousliy the verbage misled rather then educated me. I will leave it to W if he does the job in the next day or so, before returning to the patent (not very :"fun reading") and trying to dope out what it really means. If the figures were clear on my computer, I probably could figure it out OK.
Today is Kirchoff’s birthday. According to Social Security records, he was born April 29, 1904. He joined the company (Lima-Franklin-Balmar?) in 1937, became vice-president of engineering in 1952 and president in 1955.
“Julius J. Kirchhof, former president of Franklin Railway Supply and chief designer of railway poppet valves in the U. S., died at age 70 on October 4, 1974.” (Trains)
If his patent for Locomotive Steam Controlling System is where the answer is, it’s somewhat clearer in PDF. I copied the sideways diagrams to Paint then rotated 90 degrees. But I cannot summarize tech material. Make that, hardly comprehend. I looked up wire-draw in the dictionary. The definition seems to describe the current question.
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US2518024.pdf
Just to be sure, the patent is 2518024. I strongly recommend downloading the .pdf and then working from that, as it can be enlarged as needed and the OCR foulups are not present.
The important sections are the discussion of the cams, at 8:30 to 8:71, and the following discussion of action in 8:72 to 9:19. I find very little chance that a MIT graduate will have difficulty reading these sections!
The discussion of mid position is 7:36 to 7:57, if anyone is wondering how drifting is accomplished. I remain unsure of the degree to which this configuration of poppet valve is affected by cinders or combustion gas being sucked through in the absence of the bypass action described. (Dabeg proponents would probably say 'very little' but I have my doubts... ;-} )
Interestingly, there is a fairly complete discussion of the potential issues with variable-profile-cam RC systems starting at 8:59, which is enlightening when compared to the description of Franklin RC in the 1947 Locomotive Cyclopedia and then the Long Compression setup (patent 2518403), and the British Caprotti setup on Duke of Gloucester 71000, which uses discrete cam steps.
I think part of the problem Dave is having is that the actuating mechanism on 2628/611 is radically different from what is noted in the patent (at about 2:27 to 2:35). A Rotair-type valve is not used; instead, there are two little 'button' valves of the type found on contemporary garage lifts, and the gear remains 'locked' in whatever operating direction is selected once it has been reached, while (apparently) the control handle returns to its 'full upright position' (which is where you can see it in some of the running pictures of the locomotive). There are apparently no lights or indicators of any kind showing what direction is engaged.
If I were setting this up, the haptics would be different -- the operating handle would remain in forward or reverse angle, as appropriate, or there would be some clear indication of 'gear engaged and locked' for forward, reverse, and mid-cam engagement.
I'm still looking for the letter. It's mentioned so often in the discussions regarding this system that I can only suppose nobody searching the Web has found them yet.
Oh gosh. Mercifully only 25 letters to E-liminate. Quoting Julius, if it helps…
Because of the above-described cam profile, different effective cut-offs are provided at different operating speeds of the locomotive. Thus, at very low-speed operation or at start, the effective cutoff (in the specific example given above) will occur at 85% of the piston stroke, since, at start or at very low speed, even a very small valve opening is adequate to admit the starting steam. As the speed of the engine increases, wire drawing occurs in the portion of the stroke corresponding to portion B of the cam, since at this time the valve opening is very small and insufficient to pass the volume of steam required to provide 85% effective cut-off. Similarly, at still higher speed, wire drawing will even occur in the portion of the stroke corresponding to portion B of the cam, as a result of which the effective cut-off is again shortened, the progressive shortening of the cutoff being shown by the legends applied to Figure 9.
From the foregoing it will be seen that by appropriate plotting of the cam profile a number of different effective cut-offs may be obtained without requiring any adjustment of the cam mechanism or of the valve gear. For this purpose the cam profile may either have a gradually inclined surface in the region from the main lobe down to point d or may have arcuate surfaces interconnected by inclines, as in the form herein illustrated.
A similar action is obtainable by appropriate plotting of the exhaust cam profile. Preferably, according to the invention, the exhaust cams for forward and reverse operation (see cams 71 and 73 in Figure 5) are provided with at least one portion such as indicated at E, of substantially lower height than the main lobe 126, which portion (E) serves to delay the point of compression at start and at low engine speeds. At relatively high speed the effective compression point is advanced, since the extent of exhaust valve opening provided by cam surface E is not sufficient, at the higher speed, to fully exhaust the cylinder.
The employment of cams of the type above described is of especial advantage in association with a control mechanism of the 2-position type, since, notwithstanding the fact that the engineers control has only one forward position and one reverse position, the mechanism itself automatically effects variation of cut-off (and also, if desired, of compression) according to the speed of operation of the engine.
The utilization of cam profiles of the type above described is further of especial advantage in a mechanism incorporating separate rotating cams for forward and reverse operation, since the automatic variation in cut-off or compression or both does not adversely influence other valve events, such as the points of admission and release, when the engine is reversed.”
From the foregoing description it will now be apparent that the present invention secures an approximation of the results of progressively adjustable valves and valve gears, without actually employing the complications of step-by-step or progressively adjustable mechanism anywhere in the system, from the control lever in the cab right down to the valves themselves. In short, the valve actuating, controlling and reversing mechanism is very greatly simplified, while preserving approximation. of the variable valve events which are desirable in locomotive engines; and the approximation is sufficient for certain types of service (such, for example, as switching engine service) merely by the use of two or three stages of valve lift effected by the intake cam, preferably with approximately equivalent stages in compression events as effected by the exhaust cam.
Some understanding of the flow of steam is essential for understanding all the above, and i confess i still have a lot to lelarn. But the principle is now clear, and thanks W, all hats off to you!
E is not the letter... but this thread has gone on far enough.
It's Franklin type D ("type C" probably being the Long Compression variant of rotary-cam, which was never successfully sold).
I say W gets the next question.
U.S. Army 611 is a treasure worth learning about. Thanks, Overmod.
Who was the 2nd chief engineer of the Long Island Rail Road?
wanswheel Who was the 2nd chief engineer of the Long Island Rail Road?
I think it was L. O. Reynolds who held that post in the late 1830's. But he may have been the LIRR"s first not second Chief Engineer.
Mark, I see L. O. Reynolds’ name in American Railroad Journal, near the top of a page headed “Description of the Long Island Railroad.” That’s a continuation (conclusion) of his report on the Central Railroad and Banking Company of Georgia, from the previous pages.
http://libsysdigi.library.illinois.edu/OCA/Books2010-06/5088829/5088829_7/5088829_7.pdf
He worked on several railroads before and after Long Island (1835-36). He was born in Wilmington, NC on October 3, 1801 and died in Brooklyn, NY on February 16, 1853.
http://footage.shutterstock.com/clip-4847339-stock-footage--s-the-carrollton-viaduct-celebrates-its-year-anniversary-in.html?language=nb
Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!
Get the Classic Trains twice-monthly newsletter