Attuvian BTW, when and where is the next RWC? Scrum down . . .
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
I suspect that most model locomotives don't accumulate a great deal of mileage (or perhaps footage). I don't seem to find time enough to run mine as much as I'd like, but they usually do get a workout when they're run, due to the many grades. I don't own a locomotive to which I've not added weight, and even if I could run them much more frequently, I think that it's more likely that I'll wear out before they do.When that happens, a friend with whom I have a mutual agreement, will post a notice and link here advising of a sale of train stuff on "that other Forum".
Wayne
Apologies to John if I’m going doctorwayne If you're planning to add weight to any locomotive, make sure that if it stalls.... Gidday Wayne, having utilised your methods of adding weights to balance a steam locomotive, I’ve been told, by a couple of my fellow MRs, I’m mad (Quite possible!!) because the extra weight will accelerate the axle/frame bearing surface wear. I have really only added enough weight to balance the locomotive, it does pull better, but then my locomotives get so little running that I don’t have the proof to disprove their “fact”. I’m sure that you would have mentioned it, if abnormal wear had become evident. Cheers, the Bear.
doctorwayne If you're planning to add weight to any locomotive, make sure that if it stalls....
And gidday to you, Bear. No apologies necessary at all. I'm getting a great education from this thread, including all the inherent derivative matters. So let's include your issue and let the observers and participants sort it out as they will.
Having broached the issue of increased wear on axles resulting from any added weight, may I ask the following: just how much wear do axles get without significant additions to a factory body? I can certainly imagine that there are a fistful of major factors at play in that issue alone: materials/hardness of both the original axles and frames, lubricants or the lack thereof, running time, shape of the pocket in which the axle rides, any bearings/sleeves/ferrules that may be original issue or add-ons, perhaps even average rolling stock draw-loading, etc.
Yours is a very reasonable observation in light of the extent of this discussion. I'm sure it will get its own set of responses, particularly from heavy loco users that also keep a close eye on their maintenance. But I will offer this as a starter: you can bet that if an engine is not reasonably balanced along its driver wheelbase, there will certainly be more than normal wear on the axles that are bearing the greatest load.
As a matter of tidiness, I welcome the right person to break open a separate topic as may become necessary. Understanding, of course, that weight, balance, and wear are essentially inseparable issues.
Enjoy your Spring, mate. BTW, when and where is the next RWC? Scrum down . . .
John
doctorwayneIf you're planning to add weight to any locomotive, make sure that if it stalls....
I'm thinking about doing dual motors for my spartan cab F45, but with DCC and sound.
Steve
If everything seems under control, you're not going fast enough!
gregc....if you add weight to rebalance, re-measure the tractive force, you can re-calculate the adhesion. If the percentage goes up up, then I'd say rebalancing made a measurable improvement. but even if it didn't, there's still greater tractive force.
Not necessarily, Greg:
doctorwayne....if weight is added in a manner which increases the imbalance, loco performance suffers accordingly.
That 25% figure is pretty-much a standard, I think, at least for model trains. The real ones' traction control, and wheelslip limiting abiltities offer an advantage.
I built three of these Athearn Blue Box U-Boats...
...with two motors each...
...with each of them weighing just over 33oz....
Tests at a nearby model railroad club showed each with a tractive effort of 8.3oz., pretty-much dead-on 25% of their weight. Balanced weight isn't much of an issue in diesels like that.On the other hand, you could load up the cab of a plastic 0-6-0 with lead, to the point that the first two sets of drivers were completely off the rails, and it would pull absolutely nothing, because the rear coupler would be sticking into the ballast.Generally speaking, adding weight to steamers helps their tractive ability, and if that weight is balanced, all the better.
I built this steamer for a friend, starting with an existing brass model....
I added weight, and it was fairly well balanced at about 32oz. (loco only). While it could handle that 100oz. coal train (that took two Mikes or Consolidations to move up my long 2.8% grade) on level track, it literally stalled on the same hill: the trailing tonnage was too much, and its own weight wouldn't allow the drivers to slip, despite having a very large can motor. Since my friend's layout doesn't have such grades, and doesn't need to move such heavy trains, I took the loco apart and cut an inch-or-so off the back of the weight. The loco, of course, still couldn't pull that train up that grade, but when it stalled, the drivers slipped readily.
If you're planning to add weight to any locomotive, make sure that if it stalls (is unable to move the train - you can simulate that by coupling a car to it, then applying power while restraining the car with your hand) the powered wheels will slip. This will prevent you from burning out the motor.
it seems that the tractive force, even of a model, is some percentage of it's weight --- adhesion. Track conditions (wetness) shouldn't vary for models.
so if you weigh the model and measure it's tractive force you can detemine that percentage (~~ 25%)
if you add weight to rebalance, re-measure the tractive force, you can re-calculate the adhesion. If the percentage goes up up, then I'd say rebalancing made a measurable improvement.
but even if it didn't, there's still greater tractive force.
greg - Philadelphia & Reading / Reading
gregcI'd be interested to hear if rebalancing makes an improvement beyond that of simply adding weight....
gregc This page for Reading Company locomotives provides weight on each driver axle. These were of interest to me B8a 49412 46675 58038D8a 47575 48850I5a 41025 37447 32404 29309I10sa 70910 71510 71580 70190 I thought it was interesting that the earlier locos weren't as balanced, 40%, as the later (e.g. I10), < 2%.
This page for Reading Company locomotives provides weight on each driver axle. These were of interest to me
B8a 49412 46675 58038D8a 47575 48850I5a 41025 37447 32404 29309I10sa 70910 71510 71580 70190
I thought it was interesting that the earlier locos weren't as balanced, 40%, as the later (e.g. I10), < 2%.
The weight balancing of real steam locomotives was (and is) much more sophisticated than for models. So comparing the two is not a one for one thing.
For a real steam locomotive, all wheels are fully equalized. That includes leading and trailing truck wheels. Which means that, if you push up on one wheel, it has an effect on all the others. Rather than just lifting the locomotive up in the air, with all the weight on the lift-point.
That seems to imply that the weight on all the wheels should then be the same--the term "equalized" sort of implies it. But by changing the lengths of the equalizing arms, you can change the weight ratios on the wheels. I suspect that accounts for the variations in the Reading numbers. Whether it was "on purpose" or accidental, I can't say.
So I'd be interested in hearing if distributing the weight on a model makes a noticable improvement. I agree that as soon as one wheel starts slipping, the load on the other wheels go up making it more likely for them to slip.
i'd be interested to hear if rebalancing makes an improvement beyond that of simply adding weight.
I was surprised to read that tractive force is a function of adhesion and a value of 25% of weight on the dirvers is a common reference point. This varies with conditions -- wetness of the rails.
I'm considering purchasing an old AHM/Rivarossi Big Boy adding elephant ears and swapping the tender for two Santa Fe 52' oil tenders, I'd have to change some details on the locomotive to make it an oil burner.
I didn't know that steamers had to be balanced, quartered yes, balanced no.
Those of us who have something to share get at least as much from that sharing as the person who learns something new from it. And I think that all of us can learn new things, whether from long-time modellers or those just starting out. Isn't the point of places like this to be an exchange of ideas?
peahrens.....Have you / do you contribute to MR magazine? That would steal some of your valuable time...
Only once, Paul, and yes, it was, at least for me, time consuming. It was a Paint Shop article, on how to paint and letter diesels for prototypes which, at that time, there was no suitable lettering available. It involved painting (with a brush in those days) in the lettering colour, then applying dry transfer lettering (from alphabet sets) over that as masking devices, then applying what would become the background paint once the dry transfers were removed. That use of dry transfers wasn't my idea - I owe Art Curren my gratitude for an article he wrote on creating multi-coloured signs. My small contribution merely substituted locomotives for the signs. I sorta doubt that many folks read the article, then actually applied the method to whatever model they wished to create, and that was borne out by the fact that I did about 70 locos in the same paint scheme for modellers who frequented a local hobbyshop where I had left the locos on display for a couple of weeks (at the request of the store's owner).The models, Athearn geeps, needed removal of the dynamic brake detail and of the steam generator details for freight units, and the paint job was labour intensive: two colours applied with a brush, then lettering and striping with dry transfers, then the same two colours, again applied with a brush, but over the opposite colours. The dry transfers were then removed to reveal the contrasting painted-on lettering and striping. However, at that time, there was no dry transfer for the herald on the cabs' sides, so I did them free-hand, with a brush...
Another view of one of my original brush-painted ones...
...and one of the slides used in the article...
...and one of the real ones...
I had no idea what painters would have been charging at that time, and no one seemed to be willing to share that info. I later learned that even at its highest, my prices were more than 50% less than most were charging for very simple one-colour schemes, with readily available decal lettering.The bright side of that experience was meeting a couple of modellers who became good friends, and still remain so almost 40 years later.I painted, mostly brass, for them for many years at very reasonable prices, and it only dawned on me later that I was charging my friends for the privilege of painting for them. One is currently out of the hobby, but I still paint for the other, and the friendship of both is worth more money than anyone could ever offer.
Eventually, Atlas did this paint scheme on their HO geeps, and LifeLike Canada later came out with very nicely-rendered version, too. I was relieved!Sharing info here, while not as lucrative as writing articles, is a lot easier, and adding pictures not at all demanding of perfect exposures. I also think that the audience here can get the info they want almost "on-demand", and in return, those providing the info get responses back just as easily. Some of the latter are favourable, some not so much, and others offer alternatives, which, as I mentioned earlier, is an opportunity for all of us to learn more.
My apologies for going on (as usual) at such length, but I felt that the previous posts deserved an in-depth reply.
peahrens . . . . I can get a bit nerdy. I enjoyed the thought process. And again, your work is most enjoyable to see (and envy). Have you / do you contribute to MR magazine? That would steal some of your valuable time, but I'm not convinced that everything shown is your work alone. I'm thinking there may be several dozen talented elves cranking out at least some of your projects.
And again, your work is most enjoyable to see (and envy). Have you / do you contribute to MR magazine? That would steal some of your valuable time, but I'm not convinced that everything shown is your work alone. I'm thinking there may be several dozen talented elves cranking out at least some of your projects.
Paul,
Like Wayne, I have been able to follow along and have found your "nerdy" offerings to be insightful and thought-provoking. Once again, kids have no clue - it generally dawns on them later, when we're either already chilling underground or too addled to be able to say, "I told you so!"
As for Wayne's "elves", I'm begrudgingly thinking they don't exist at all. I'm willing to bet that we have in him a prime example of the guy who 1) knows his tools (and where they are), 2) has used them constantly for many years, 3) whose fingers are as fast as his mind and, 4) has stored up in that mind a huge reservoir of creative techniques and shortcuts born of what's worked and what hasn't. Yeah, I can build a bookcase from scratch in my garage. But it will take me four times as long (and won't look as good) as the identical one an old friend of mine could whip up seemingly out of his back pocket. He's accomplished in it, and I'm not so much - yet. It's that perfect marriage of capacity and experience that we all admire and strive for. The real blessing is that Wayne and those like him offer it up to us all so freely.
It is one of the richest rewards offered by this hobby. And it is also transferrable to a whole host of endeavors in other areas of life. Just another reason why we all ought to make extra efforts to get younger folks into this business. It's a lesson that I'm suspicious is not as prevalent elsewhere at it used to be. And a lesson that enables folks to become more than they might otherwise have thought they could be.
Hadn't intended to be so reflective. And apologies to those that have found this perhaps a bit tedious. I'm just being grateful for having found in this hobby far more than I ever expected.
doctorwayneAll I know is that my two purchased-new Athearn Mikes were useless pullers and the modifications made changed them into useful locomotives, capable, when doubleheaded, of handling a 100oz. train on my long 2.8% grades. The improvements lead me to purchase four more of them, all only slightly used, likely due to their poor performance.
Wayne, this triggers some final technical thoughts on weight, balance, etc:
1. As long as the center of gravity is within the driver axles, the loco does not (on level track) have a tendency of "tilt" towards the pilot or cab, so ALL added weight must fall only upon the drivers (which is good, of course). The reason is that the lead and trailing trucks only have a downward force of the truck weight plus its spring force (when compressed partially on level track). Added weight portions can not transfer to the lead or trailing truck as those wheels see only their weight and that truck's spring force, which is constant as it is compressed the same before and after. (Ignoring if any driver springs compress more, which creates a secondary effect in theory by compressing the truck springs a bit more.) Back to the main point, your Mike's traction after weight addition should be essentially (16.75 oz. / 12.5 oz. ) x 100 = 134% of original, which is significant for performance, as we know, and quite impressive given the severe limitations on room to add weight. One could enhance the precision of this calculation by looking at the weight on the drivers only (before & after), subtracting the trucks' weight and spring compression force on same, but that might increase the % improvement by only 1% or so.
2. You can add to that improvement, if were known, the amount of gross weight transferred to the drivers by removing the trailing truck spring, which was "stealing" (by supporting) some of the loco gross weight from the drivers, keeping them from maximum (no sprung trucks) potential traction. All in all, you are probably in the 35-40% traction improvement zone.
As Forrest Gump said" "And that's all I have to say about that". Enough. If you ask my kids, they may advise that I can get a bit nerdy. I enjoyed the thought process.
Paul
Modeling HO with a transition era UP bent
Thanks for your comment, John, but the multiple locomotives (or freight cars passenger cars, or structures) all identical or almost so, are my method of dealing with repetitive tasks which can quickly become boring. If I figure out how to do something previously unfamiliar to me, I'd rather make that improvement or use that new idea to complete all, or at least as many as I feel will ever be needed, in one project. Returning years later to recreate something I've built in the past is difficult...partly because I may have forgotten some of the process, but more likely it's even more boring the second time around. The enjoyment is, for me, in figuring out how to do something, and then completing it.
A friend had often commented on my scratchbuilt scale test cars, and was lamenting the fact that the Walthers ones weren't currently available, and that mine looked so nice. Always a sucker for a compliment, I commented that if I had a suitable truck to build it on, I could make him one.
Well, wouldn't you know it, but he comes up with a somewhat suitable truck. I wasn't totally enamoured of the truck, though, and since I was busy with other projects, was able to put it off for a while. I don't recall where, but I finally found a single, more suitable truck. Out of excuses, I inspected one of my earlier builds (one of five built at the time, with two going to other friends - the current friend was unknown to me at the time), trying to recall how I had constructed them.Here's one of mine, at the tail end of a train...
Once I figured it out, the project was done fairly quickly, but the latest one is, I think, better done than the originals....I guess that my skills must have improved, but how long before I decide that my scale cars need upgrading?
peahrens...For any that have read this far, I've found it an interesting refresh plus learning experience. Hopefully not too boring....
I read it all and did find it interesting and informative, and not at all boring. I am, however, not scientifically-minded at all, so am not really qualified to dispute your conclusions. All I know is that my two purchased-new Athearn Mikes were useless pullers and the modifications made changed them into useful locomotives, capable, when doubleheaded, of handling a 100oz. train on my long 2.8% grades. The improvements lead me to purchase four more of them, all only slightly used, likely due to their poor performance. Two of those are in-service, while the other two await conversion to change their appearance to match a couple of different prototypes, but they'll also get the performance upgrades.A pair of my slightly modified Bachmann Consolidations could handle that same train, but I had mistakenly thought that I had at least changed the plastic air reservoirs for lead-filled brass tubing. I finally got curious enough to check, and was surprised to find the plastic ones still in place, but not for long...
I didn't bother modifying the stock weight in the same way as on the Athearn locos, but did add weight on the frames, inside the domes, smokebox front, and air reservoirs, and on the cab floor and in the cab ceiling. Weight now, loco only, is about 16.25oz., with five such locos in service. I have another three awaiting conversion to match specific prototypes, but hope to get them at least to a similar, if not higher, weight.
If you are dealing with DCC, a short would likely cause a system shutdown, while a contact problem would not cause a total shutdown. I recently had a contact problem with a Mantua 2-8-4. I fixed the problem by adding a keep-alive decoder. They really do wonders to prevent that contact problem, in DCC mode of course.
Simon
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garya...it seems to short out on Atlas turnouts near the frog...
I'm guessing that rather than a short, what's happening is that the loco is losing contact with the track. I had a number of Atlas turnouts which worked well with all of my Athearn Mikes (I did mention, but perhaps only in the linked-to thread, that I added Bachmann pick-ups to the tender trucks on my Athearn Mikes), but when a visiting friend brought several brass locomotives to run (Mikes, Mountains, and Northerns), all of those locos stalled on the same turnouts.It seemed unusual that all of those locomotives would have the same problem, so I looked to the turnouts for the problem.What I found was that some code 83 #6 Atlas turnouts had frogs that were too high. The brass locomotives, with their usually too-stiff springing, and at low speed, ended up with the non-insulated drivers on the unpowered frog, and none on that side in contact with the live rail before or after the frog. In contrast, the softer springing in the Athearn locomotive allowed the wheels to move up and down as they should, and at least one wheel would be receiving power as the loco passed over the frog. Even if the Athearn loco was sprung like the brass ones, the fact that the tender collected power from both rails (one truck for each rail) allowed it to continue without hesitation.After my friend had left, I checked all of the Atlas turnouts by placing a metal straightedge across the rails (power off, of course) and sliding it along the railtops to the frog. Any which revealed the frog to be too high were quickly remedied with judicious use of a mill file. (Based on the placement of the turnouts, it appears that all offending ones were purchased at the same time, and likely from the same production run).If some drivers aren't contacting the rail, check that the wheel wipers aren't mis-bent and somehow causing the problem. The drivers are sprung, but it's a bit more of a job to get at them, and I doubt that the problem would be there.
doctorwayne Even if the loco is picked up, with thumb and finger on the running boards in a light grip, and at the mid-point of the driver wheelbase, you can get a pretty-good sense of how well it is (or isn't) balanced.Prior to doing the modifications outlined in that thread, I placed one of those locos and its tender on the layout, then draped a "saddle" of folded sheet lead over the boiler, and while restraining the tender with my hand, applied power. The locomotive attempted to surge forward, then immediately slipped its drivers, a sure sign that the weight was not too much for the motor to handle. As I recall, that "saddle" was well in excess of two pounds, and of more volume than could ever be fit into that locomotive. The Athearn USRA locos (Mikados and Pacifics) both came with springs on the trailing truck, and I think that its main purpose was an attempt to shift some of the imbalanced weight forward.
Even if the loco is picked up, with thumb and finger on the running boards in a light grip, and at the mid-point of the driver wheelbase, you can get a pretty-good sense of how well it is (or isn't) balanced.Prior to doing the modifications outlined in that thread, I placed one of those locos and its tender on the layout, then draped a "saddle" of folded sheet lead over the boiler, and while restraining the tender with my hand, applied power.
The locomotive attempted to surge forward, then immediately slipped its drivers, a sure sign that the weight was not too much for the motor to handle. As I recall, that "saddle" was well in excess of two pounds, and of more volume than could ever be fit into that locomotive.
The Athearn USRA locos (Mikados and Pacifics) both came with springs on the trailing truck, and I think that its main purpose was an attempt to shift some of the imbalanced weight forward.
I have an Athearn Genesis Mikado, and it seems to balance over the third driver. It has issues--it seems to short out on Atlas turnouts near the frog. I ran it on my friend's layout, which uses Peco track and turnouts, last night and while it didn't short out, it seemed to have problems having all the drivers staying on the rails--it looked like the second driver was "off" the rail. I wasn't derailed, but I couldn't get all the drivers to sit flat on the railhead.
I have to admit I'm a little afraid of performing the surgery the good Doctor prescribes--I'll start by adding some lead weight to the front end to see if it helps. But I may have to break down and start cutting.
Gary
doctorwayne peahrens ...if we had a 0-8-0 with center of gravity not over the midpoint of the 4 axles, let's say towards the last axle, the forward axles would lose tractive effort and the rear axles would increase their effort and it would tend to come out near the same. Two caveats come to mind. If the drawbar to the tender started picking up some of the out of balance force, some of the loco weight would transfer to the tender for a net (tractive) loss. If nearly all the weight were over the 4th axle, it would be ok (if that axle not on an especially slippery area)??... It seems to me that if only one wheelset were bearing the bulk of the weight, then yes, you'd think it would still be okay, but were the weight balanced, the friction of eight wheels would, I think, translate to more applied tractive effort. Given relatively equal specifications an 0-8-0 was generally more capable than a comparable 0-6-0. Wayne
peahrens ...if we had a 0-8-0 with center of gravity not over the midpoint of the 4 axles, let's say towards the last axle, the forward axles would lose tractive effort and the rear axles would increase their effort and it would tend to come out near the same. Two caveats come to mind. If the drawbar to the tender started picking up some of the out of balance force, some of the loco weight would transfer to the tender for a net (tractive) loss. If nearly all the weight were over the 4th axle, it would be ok (if that axle not on an especially slippery area)??...
It seems to me that if only one wheelset were bearing the bulk of the weight, then yes, you'd think it would still be okay, but were the weight balanced, the friction of eight wheels would, I think, translate to more applied tractive effort.
Given relatively equal specifications an 0-8-0 was generally more capable than a comparable 0-6-0.
First and foremost, Wayne, your modeling is incredible and your very complete (with photos) make it most interesting. Maybe in my next lifetime...
If I may, I find exploring the traction issue a bit more of interest, so read on or ignore as you may be interested in that angle. Purely for interest...
I've reinforced my conclusion that the center of gravity being within the (driver axles / wheelbase is a critical issue, but off-center within that wheelbase is not a significant issue from a traction angle.
The key thing is the equation (see link above) where tangential friction force (traction at a wheel rim) equals, and is proportional to, only two things:
1. The "normal" (vertical) downforce (weight) applied at the wheel rim / rail interface
2. The "coefficient of friction" for that type interface.
Per Wiki, a USRA 0-6-0 had a loco weight of 165,000 lbs (27,500 lbs per wheel) and a tractive effort of 39,100 lbs. That divides to a design coefficient of friction of 0.237. The tractive effort (friction force) is 39,100 / 6 = 6,517 lbs force per wheel (assuming equal weight on each). Using this example, if the mid axle were too high and those 2 wheels suspended, the 165,000 lbs downforce would be on 4 wheels, or 41,250 lbs per wheel. Each wheel would provide 41,250 x 0.237 = 9,776 lbs force tractive effort, the weight on the rim times the coefficient of friction (a characteristic of the rim steel against the railhead steel). The 4 wheels would provide 9,776 x 4 = 39,104 lbs tractive effort in total. Assuming the loco can provide enought HP to get the wheels to the point of slip beginning, where static friction force is exceeded and slip begins. (Then you get into dynamic friction, where the coefficient is different.....).
One might find this counterintuitive in some ways. For instance, with more weight on each of the 4 wheels in contact with the rail, the rail may deform more and create a larger contact area. But as long as the coefficient of friction charactistic of the wheel rim and rail is what it is, the area of contact is not in the equation. The maximum tractive force is only proportional to the weight appied to the contact area and the coefficient of friction.
Similarly, a USRA 0-8-0 had a loco weight of 220,000 lbs and tractive effort of 51,042 lbs, computing to a 0.232 design coefficient of friction. If one (or two) of its pairs of wheels were suspended, the 6 (or 4) remaining wheels would compute to the same total 51,042 lbs tractive effort. I conclude that the idea of the 0-8-0 was more tractive effort (than the 0-6-0) desired, which with the typical (constant) coefficient of friction, meant a proportionally heavier loco was required to create proportionally more traction (no matter how many drivers).
Which got me wondering why 0-8-0's were developed. Why not make a 0-6-0 (or 0-4-0) that weighed the 0-8-0's 220,000 lbs? I presume there were several reasons, perhaps rail capability per wheel, or weight per axle bearing, wheel rim wear affected by weight, etc.
For any that have read this far, I've found it an interesting refresh plus learning experience. Hopefully not too boring. Mr. Gralla, Madison H.S. physics teacher, not only last century but also last millenium(!) would be proud.
Attuvian But I'm inclined to think that any platform upon which the engine is placed for the test must extend equal distances from the mid-point of the drivers' wheelbase. If not, I would think the platform itself will be unbalanced and throw the whole test out the window.
But I'm inclined to think that any platform upon which the engine is placed for the test must extend equal distances from the mid-point of the drivers' wheelbase. If not, I would think the platform itself will be unbalanced and throw the whole test out the window.
This is an important point, if you're using this method. You are balancing BOTH the locomotive and the platform.
During setup, put only the platform on the dowel and balance it. Make a mark on the platform for this point. Since the platform is almost surely of equal cross-section on its length, the middle of the platform will be the balance point of the platform.
When you place the locomotive (no tender, by the way) on it and balance the assembly, the mark on the platform will have to line up with the dowel. You essentially move the loco on the platform to find ITS balance point.
I think Paul is right about the balance point being anywhere within the driver wheelbase, but only as a first approximation. If nothing else, having it too far from the middle might encourage derailment tendencies on the light end.
Wayne mentioned placing a saddle of lead over an engine. An experimentalist might used this technique to determine how important centering the balance point is--just reposition the lead and see if it makes a difference.
Ed
Yup, both sides...
From the photos I could find of locos with overfire jets, all were coal burners.
doctorwayne Those are known as overfire jets...they used steam to force more air into the firebox. I'm not sure if it was only to improve loco performance or also an attempt to control smoke from the stack. Wayne
Those are known as overfire jets...they used steam to force more air into the firebox. I'm not sure if it was only to improve loco performance or also an attempt to control smoke from the stack.
doctorwayne ...as are the air tanks under the running boards... Wayne
...as are the air tanks under the running boards...
What are the gizzies hanging beside the firebox like so many stored fishing floats?
Holy smokers, Wayne. If there is an available space, it gets loaded with lead. Have you registered any of your locos as potential deadly weapons?
Attuvian....I'm inclined to think that any platform upon which the engine is placed for the test must extend equal distances from the mid-point of the drivers' wheelbase. If not, I would think the platform itself will be unbalanced and throw the whole test out the window.
Yes, the balance platform, by name and nature, is of course balanced when not in use. If you put a loco, balanced at the mid-point of its driver wheelbase, with that mid-point atop the fulcrum of the balance, it matters not if the loco's pilot extends further from the pivot point than does the rear of the cab - the balance is for weight only, not length.Properly balanced, everything forward of the mid-point of the driver wheelbase weighs the same as everything aft of that mid-point.
This one was harder to balance than any of my other steamers...
....and still isn't all that great for moving much of anything. I had intended to use it as a pusher on the long grade up to the layout's second level, but I added all-wheel pick-up to both tenders, which creates too much drag. On a positive note, it can run a fair amount of distance into an unpowered siding, though.
Steam pipes are lead-filled tubing...
...and those atop the boiler, too...
...and both engines have lead weights atop their respective gearboxes...
...and in the sand domes and top of the smokebox, too...
doctorwayne . . ., the friction of eight wheels would, I think, translate to more applied tractive effort. Given relatively equal specifications an 0-8-0 was generally more capable than a comparable 0-6-0. Wayne