Railway Preservation News

USATC 2-8-0 No. 611
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Author:  EDM [ Sat Jun 30, 2012 10:14 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Just to add a little to the 'steam believer' thought: even though diesels were well developed for marine use during WWII, look at the Liberty ships. They had a time-tested triple-expansion steam engine that was real easy to understand and repair. A diesel plant, stationary, rail or marine, was still in the minority, although the numbers were on the rise.

Now, before someone takes exception and mentions the military six-axle RS-1 and the humpback Whitcombs and all the other US/ATC units, remember that we set up special Railway Operating Battalions with well-trained troops to keep those units running. But steam was still more universal overseas for many years after WWII.

Author:  Overmod [ Sat Jun 30, 2012 10:33 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

To add a little logistics here:

One great advantage of a 'steam locomotive' over diesels is that it does not require supply of a refined liquid fuel that would have to be assured via forward supply. Much of the history of armored campaigns in the WWII years would have been very fresh in planners' minds as we went into the Korean conflict, and the idea of motive power that could be very simply driven, fueled from surrounding forests if need be and watered with easy dosed treatments, would have to be interesting.

With respect to the German motor locomotive, I have seen some indications that we offered to return the engine to the German federal railways for the cost of shipping (they didn't want it). I suspect the decision to 'scrap' was similar to the reason why the original M10000 motor train was scrapped -- wartime 'patriotism' trumping any desire for preservation. By the early '50s the locomotive was an odd foreign prototype that nobody really wanted... and about the antithesis of anything useful in a military sense... ;-}


Author:  Dave [ Sun Jul 01, 2012 9:02 am ]
Post subject:  Re: USATC 2-8-0 No. 611

brettcog2000 wrote:
The eccentric boxes are both marked, but at you can see in the pictures they are not mounted on the locomotive. They will have to be mounted, and then we can get the drive shafts put back on the engine. Once that happens we will have to effectively re-time the locomotive from scratch, because there is no way to tell where the eccentrics should be set against the motion of the cams as you have described. The cams do have to be set against the drive shaft, but also set against the eccentric boxes at the proper rotation on the main pins.

More thinking, less worrying please.

Assuming there isn't any marking on any of the parts once things get cleaned up, it is a failry simple matter of rolling her back and forth and fiddling with the fine adjustment until the lead (if any) is equal at both deads centers in both forward and reverse gear, or at least an approximation of an average of it.


Author:  Overmod [ Sun Jul 01, 2012 10:04 am ]
Post subject:  Re: USATC 2-8-0 No. 611


Dave, this is a rotary-cam poppet-valve engine. Doesn't have 'lead' you can measure in the normal sense. The valve 'events' are relative to the angular cam position as transmitted through the followers and pushrods to the valves (and the valves are spring-returned, so each one will be fine-adjusted individually) but this is no more difficult than the corresponding adjustment of pushrod length in IC engines... when nobody has put in any means of tappet adjustment...

The only reason to 'roll the engine forward and backward' is to use the tram method of determining FDC or BDC 'precisely'. It is very likely that you will do the same thing in the cambox (perhaps looking at the valve through the port with a flexible borescope until you *just* see the valve start to lift off its seat) to set the angular position. (It was my impression that good practice was to matchmark RC cams/boxes in some way to indicate from the outside where the angular cam position was when the valves started moving -- precisely to aid in setting things...)

If the camshaft is assembled correctly, "setting" one valve (as above) sets all four for that side/cylinder. Specifically, exhaust clearance (if this locomotive follows Kirchhof's patent spec) is preset via the profiles and the way they are timed when the shaft is put together. So I'd advise you set the timing on this engine from admission unporting, as being more 'fixed' as a precise (and quick!) function of cam profile.

You then roll the engine to *precisely* the number of degrees relative to dead center that you want the inlet valve to start opening, preload the gears in the 'right' direction in case there is any wear or slop, and bolt up the free end of the shaft.

Important note (imho) --you don't really care if the angular position of the gearbox on the main driver 'eccentric crank' is precise; just that any lash or play in the teeth, or endplay on the worm, is taken up -- the gearbox isn't a positional encoder, just analog coordination and power drive. Likewise, where the universals on the shaft are, or how the worm engages the cam drive at the cambox, are not significant. (There is a tiny bit of positional uncertainty in the U-joints; you could eliminate this either with double universals or Rzeppa joints, but I don't think I'd obsess over this point on this locomotive! ;-})

On this setup, unless I am mistaken about a conjugating shaft being absent, you will do the procedure separately for each side. Be prepared to check whether the shafts counterrotate! With the engine at the correct advance for the cam on one side, things should be 'just right' for the other side. (On the other hand, if there is some quartering error or mismatch in main-rod length or whatever, you could independently time that other side and restore effective 'perfect' timing for events on both sides...)

One of the big 'uncertains' as far as I'm concerned is the number of degrees of advance that these profiles actually use. You will note that the patent discusses compression (col 9, lines 7 to 19). I would expect there to be some compromise between the effective compression observed at different crank angles under different loads and throttle openings and the amount of effective pressure both in the expansion (with the poppet valves 'modulating' as they close) and as a partly-closed throttle or sliding-pressure-fired boiler might supply at the valves. Yes, I'd expect some very careful profiling for the cams, and careful grinding and setting of the cams on the shaft. But I do not have the special experience of someone like Vernon Smith with respect to effective RC cam design for timing and duration of these valves. And to my knowledge, any documentation revealing this is either lost or currently unavailable. That may mean that some experimentation with effective angle of advance might be necessary for best running -- the good news being that once discovered, simple marking ought to establish it, and subsequent adjustments for wear would have a 'known-good' starting point...


Author:  whodom [ Sun Jul 01, 2012 10:44 am ]
Post subject:  Re: USATC 2-8-0 No. 611

Here are 3 photos that may help with the "re-timing" of 611's valve gear discussion.

I found this photo yesterday showing the valve gear drive on the engineer's side of the locomotive:


This photo shows the orientation of the U-joints and clarifies how the cut shafts will have to be welded back together. Note how all 4 U-joints on the 2 halves of the shaft align. It may be that they'll luck out and find some tell-tale mark on the two pieces of the cut driveshaft that will make it obvious how the shaft should go back together.

Here's a recent closeup photo of the cam drive gearbox on that side of the locomotive I found at another forum:


There's at least one mark at the top of the stationary portion of the box but there are two marks on the hollow shaft so that's no help in determining the correct orientation. The camshaft has to rotate at the same speed as the drivers so I'd say odds are good both gearboxes at the ends of the driveshafts have a one-to-one ratio.

Here's a cross-sectional view of the gearbox and valves from the patent:


As stated in the patent and shown above the cam lobes are keyed to this shaft so there's no worry about those being "off" by a few degrees. I think what all this means is there will only be 2 obvious ways that the locomotive can be timed and it'll either be correct or backwards. I think you'll also be able to just look down on either side of this gearbox to see if a valve is being opened (see parts 61a, 61b, 104, and 105 above). The bottom line is I don't think there will be any way to get it "off" by a few degrees because of the way the thing's constructed.

BTW- I found a post on another forum yesterday by someone who says they have Franklin literature left in the Ma & Pa's shops when the 611 operated there in ~1950. That literature might answer ALL the questions about how to set this up.

Author:  filmteknik [ Sun Jul 01, 2012 11:21 am ]
Post subject:  Re: USATC 2-8-0 No. 611

Every time I see something like that I always wonder if there isn't a simpler way to pick up rotary motion off a rotating axle than a drive shaft hooked to an eccentrically located drive pin. Couldn't they have done a Spicer drive off the middle of the axle? It could be centrally located and drive both sides or for redundancy have two, maybe from different drive axles, offset to one side or the other. It just seems counterintuitive to get rotary motion that way, when there are axles one might connect to in some fashion.


Author:  whodom [ Sun Jul 01, 2012 11:28 am ]
Post subject:  Re: USATC 2-8-0 No. 611

filmteknik wrote:
Every time I see something like that I always wonder if there isn't a simpler way to pick up rotary motion off a rotating axle than a drive shaft hooked to an eccentrically located drive pin. Couldn't they have done a Spicer drive off the middle of the axle? It could be centrally located and drive both sides or for redundancy have two, maybe from different drive axles, offset to one side or the other. It just seems counterintuitive to get rotary motion that way, when there are axles one might connect to in some fashion.


Steve- I've seen at least one (probably more) rotary cam setup that used something just like that. As always though, the drawback is that locates machinery down between the frames where no maintenance guy ever wants to go, and the cam drive gear box would have to be buried in the cylinder block where it'd be even harder to reach.

It seems that the most successful locomotive poppet valve systems (Caprotti and later Franklin systems) all used something just like the setup on 611.

Author:  Dave [ Sun Jul 01, 2012 2:00 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Bob, lead differential can be very easily measured by means of micing the cams or inserting a feeler gage between the valve and seat at both ends and comparing them. I am assuming lead because the value of lead was recognised across many varieties of valve gear by that time. It really is easy.


Author:  Overmod [ Sun Jul 01, 2012 5:31 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Guys - that gearbox IS like a Spicer drive. The 'eccentric crank' is oriented so its pin is exactly aligned with the axle centerline. The big gear in the gearbox is fixed. The 'universal' in the strut to the gearbox is only there to keep the box frame from rotating; that strut is not itself a drive (I think this is what may be leading to some confusion, as what I'm familiar with seeing is pin-joints on these struts, as illustrated in Fig. 1 of the '024 patent (which illustrates very clearly what the gearbox does -- see also col. 4 lines 4-39); I suspect use of the U-joint is to standardize all the flexible joints with one part number, and perhaps simplify maintenance.

All the Franklin RC drives I have seen have the multiple-shaft design with the long 'center bearing'. I always attributed this to reducing unsprung mass and reducing torsional issues (compared to the long shaft illustrated figuratively in Kirchhof's patent drawing).

Now, I would note that any Spicer axle drive I have seen is a WHOLE lot more involved to remove or replace than a gearbox attached to an axle extension -- and that is what this crank arrangement is, a means of providing a coaxial axle extension on the 'outside' of all the crank throws. Yes, you could mount this on an axle; the Caprotti patents have it there. But one of the big reported issues with Caprotti was how difficult maintaining the inside gearbox was...

Yes, you could have a single drive to the cambox; the original illustration of Albert Reidinger's valve drive I saw (in the Ransome-Wallis Encyclopedia of World Railway Locomotives lo! these many years ago) only shows the 'return crank' and gearbox on one side.

I believe this locomotive [edit: I switched gears here; I mean 611] does not have a common camshaft across the width of the locomotive, and each side is driven independently (and set independently) from its own box. One reason for this may be that a full-width camshaft driven from one end might have to be made much more torsionally rigid, and the required very stiff return springs on the poppet valve might exacerbate torsional stresses (anyone remember GM 5.7 liter diesels, or the long version of the Alco 244?)

Here is the thing, now that I have seen a couple of the detail pictures: It is possible that the shafts were made up in jigs, precisely aligned so that when the welds were dressed and the shaft primed and painted, all the installation bolt holes were perfectly aligned. If that is so, then repairing the shafts would be no more complicated (in theory) than re-creating those jigs, and doing the cutting, welding, and stress-relieving with all the parts clamped up in the 'correct' register. Doubt it would take more than a few hours to make the jig, either.

As I noted, there isn't any inherent reason why the shaft itself needs to be 'aligned' with anything other than as a convenience for rapid replacement of 'FRU' driveshafts. On the other hand, if there is a 'vernier' adjustment in the driveshaft system itself, I don't see it. I would not expect the angle of any of the U-joints, or the angular position of the gears and worm in the drive gearbox, to have any importance other than to get the flange holes to line up "properly" at the three joints that are bolted; everything with the timing could be accomplished just fine by bolting up the attachment from the shaft to the cambox with the drivers at the right position, and the cambox set to the right point PROVIDED all the holes in the shaft flanges line up correctly. (The alternative is to have some form of 'vernier' adjustment inside the cambox drive itself, but as you can see from the accord between Kirchhof's figure 2 and the cambox detail picture, the only way to change the alignment between the sleeve with the driven gear (76) and the cruciform alignment member (66) is to physically unbolt the cam stack and turn the latter, and that just CAN'T be a good idea anywhere but in a high-precision shop environment.

(I note that the 'hollow shaft' corresponding to 76 appears to have been made in two pieces and welded, which may be the source of the 'marks' that were previously referenced...) I do not think these are timing or alignment marks.)

I do note that in the picture of the end of the shaft, the cam is traversed to its full lateral position (meaning that the engine was in gear when the picture was taken). That might be a guide as to how far the shaft will traverse.

I'm sure the engine will run quite happily over a (relatively) wide range of angular misalignment, too. So in all probability I'm overestimating the required precision, and the 'slop' represented by bolting the shaft 'one bolt hole over' in one direction or the other isn't that significant.

(But why settle for average if you can think a bit and do it better? ;-} Indeed, all that would need to be 'changed' to facilitate vernier adjustment would be microsplining just one of the flange joints and elongating one or both sets of bolt holes to allow fine clamping adjustment... )


Author:  whodom [ Sun Jul 01, 2012 5:59 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Here is the thing, now that I have seen a couple of the detail pictures: It is possible that the shafts were made up in jigs, precisely aligned so that when the welds were dressed and the shaft primed and painted, all the installation bolt holes were perfectly aligned. If that is so, then repairing the shafts would be no more complicated (in theory) than re-creating those jigs, and doing the cutting, welding, and stress-relieving with all the parts clamped up in the 'correct' register. Doubt it would take more than a few hours to make the jig, either.

RME- the driveshafts look much like car or truck driveshafts, and shops that specialize in working on them are pretty common. These shops could handle building a driveshaft from scratch or shortening or lengthening an existing one for cars & trucks, and they'd have the jigs and tools to do the precision alignment and welding, and balancing afterwards. Repairing one of these driveshafts would be be a simple operation for such a shop.

My comments regarding the U-joints refer to the fact that the U-joints at either end of one of the driveshaft segments have to be "phased" correctly- i.e.- aligned with one another so that they flex correctly to allow the gearbox at the axle to move up and down with the suspension travel. Since it appears that the valve gear (at least on the left side of the locomotive) has never been disassembled apart from cutting the driveshaft near the "driving" gearbox and removing the gearbox and eccentric crank from the main pin, it seems there are the only question is the orientation of the two cut driveshaft pieces and therefore there are only 2 ways the gear on that side of the locomotive can be put together (correctly or 180 degrees off). I don't think it'll be difficult to determine the correct orientation.

Odds are there are splined telescoping joint(s) at the "stationary" portion of the driveshaft (just like with w 2-piece auto driveshaft), but apparently that joint has never been disassembled so they don't have to worry about it being off by a spline or two which would complicate this whole timing issue.

Brett's photo of the fireman's side driving gear box makes it appear either the box was disassembled and the worm was removed, or the shaft was cut off practically flush with the gearbox. At any rate, as long as they have one intact gear box that'll make repairing or remanufacturing any missing parts for the other one much easier.

Author:  J3a-614 [ Sun Jul 01, 2012 6:50 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Hugh, I concur that these shafts look like something from a truck, and like a long shaft under a long wheelbase truck or a school bus, the shaft is in multiple parts, partially, if I recall, to reduce whipping tendencies, and also to keep the shaft from being too long and heavy for the universals.

It should also be remembered that patent drawings are primarily to illustrate an idea; the actual execution of the idea will very often require changes to meet the demands of the real world, including things like the ability to balance a long, long shaft, weight considerations, and so forth.

The shaft construction seems to be that of a tube, with the mountings for the universals welded on at the ends--again, this follows modern truck and automotive practice. Take note of the welding bead at the point of taper at the rear of the shaft in this photo, as provided by Brett:


In fact, it wouldn't surprise me if the universals themselves are some sort of truck part. There would be ample precedent for this; the trucks for a lot of PCC cars were built by Clark Equipment Company, a firm that was and still is in the truck equipment business. At least until recently, it was (and maybe still is) possible to get PCC parts from Clark; the PCC did use a lot of standard heavy automotive components in its trucks.

It's also useful to remember, this shaft is only driving the valve gear, it isn't transmitting the whole power of the locomotive, as would be the case for the huge universals used in the line shaft of a Shay.

A new shaft, if needed, should be right up the alley for Miller's shop; I'm almost certain they may have had to fabricate or repair such shafts for the earth-moving equipment they handle. The main problems remain, of course, time and money (there is a "real" business there, with customers who bring in money). . .and the condition of the boiler. . .

Author:  J3a-614 [ Sun Jul 01, 2012 7:11 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Just for fun--and to recall that this class just may have raced past the 611 on the interchange track--we have C&O's L-2-a 4-6-4, built by Baldwin in 1948, and incorporating Franklin's Type B poppets, which also used a shafting arrangement very similar to that of USATC 611:

http://www.rrpicturearchives.net/showPi ... id=2379398

http://www.rrpicturearchives.net/showPi ... id=2379397

http://cohs.org/repository/Archives/coh ... s-1158.jpg

http://cohs.org/repository/Archives/coh ... -23899.jpg

http://cohs.org/repository/Archives/coh ... s-2188.jpg

http://www.cohs.org/repository/Archives ... ohs-11.jpg

Looks like a big bruiser? It is, this was the world's heaviest 4-6-4:

http://www.search.com/reference/Chesape ... _Class_L-2

Dang, this is another one I wish was still around. . .but they went in 1953, before preservation was really starting to catch on. . .

Author:  Overmod [ Sun Jul 01, 2012 11:11 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

The issue about the universals is quickly resolved with reference to the pictures: all four of them in the shaft line up exactly. Angular displacement due to suspension action on this locomotive is a tiny angle, far less than on a normal truck propshaft, and I do not think that continuous *torque* is an important consideration (as it is on some automobiles that use Rzeppa or double universals to solve the issue (as I've previously noted).

I was absolutely certain, from the pictures, that the splined section required in the 'rear' propshafts had the male spline on the short piece coming from the gearbox universal, fitting into a splined recess up the tube of the main part of the shaft. Imagine my surprise to see the picture of the back end of the RH shaft which pretty clearly to my eyes shows a welded end that incorporated the male part of the spline, which has been torqued off (see the color of the failed metal, and the little 'lip' at one side? or am I making too much of it). That would indicate that the slip joint is actually in the cylindrical piece attached to the gearbox universal... and perhaps the busted end is still in there, perhaps with jammed or bent splines, and a corresponding torque-failure pattern...

If I were designing a locomotive to be used in a theater of war... I would specify that all the joints be one size and type, and that size and type would be common to other vehicles or as a military spec for vehicles or families of vehicles. In particular, if the shaft components and universals don't match those for, say, 6x6 trucks, I'd be reasonably surprised... and convinced that somebody on the design team had dropped a rather obvious stitch... ;-}

I confess to being amused, but very pleased, with all the neat tight wiring of the bolts and fittings on that driveshaft-to-cambox connection. That's turbine-engine-quality attention!


Author:  whodom [ Mon Jul 02, 2012 1:57 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

I found an article in the newsletter "Susquehanna Sidetracks" which provides some details of the 611's (then 2628) operations on the Maryland & Pennsylvania Railroad:


It's on pages 4 & 5. The locomotive apparently worked very well after some minor modifications by the Ma & Pa not related to the valve gear.

Author:  J3a-614 [ Mon Jul 02, 2012 8:59 pm ]
Post subject:  Re: USATC 2-8-0 No. 611

Hugh, did you check pages 6 and 7? There are diagrams of the engines and a copy of a train order for when the then-2628 was on the Ma & Pa.

Of particular interest is that the engine held down one of the regular passenger runs the road still had at that time. I wonder if it was a day when the gas-electric was on one of its fits.

Also of interest was that the engine was on the Ma & Pa longer than intended. I can't help but wonder if the management liked the idea of having a locomotive in good condition for free even better than the author suggested!

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