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Post by coniston on Mar 19, 2021 21:10:22 GMT
I have started this separate thread so it doesn't get lost in 'what I've done today' as I will hopefully update with some practical feedback and further development, maybe it will spark some interest? You may remember at the beginning of the year I made a set of wheel / axle weighing scales pretty much to Greenglade's design, I wrote it up here: modeleng.proboards.com/thread/13527/clarkson-5-a3-rebuild?page=8So now the B1 is at home I thought I ought to try these out and see if I can improve the weight distribution. It certainly seems to make analysing the axle loading relatively easy although as you will see there is some error which I suspect is down to stiffness in the axle boxes. Looking at a small number of full size weight diagrams for 4-6-0 locos it seems 'normal' for the bogie complete and each driving and coupled (D&C) axle to carry about the same load, this is what I am aiming for without any further guidance. Maybe in models we can lose some load off the bogie and re distribute it to the D&C axles to improve adhesion, so long as there is sufficient load on the bogie to steer the loco round the curves and not derail? So first up I weighed the axles as they were and have been running for the last year or so. I will say now that since I have had the loco (only a couple of years) I have tried to improve the adhesion and springing but all that was done by a bit of trial and lots of error. I weighed them several times rolling the loco across the scales and bouncing the loco in between, All the numbers are in kg and shown from front to back so Bogie front, bogie rear, front coupled, Driving, rear coupled. Initial results were not very appealing showing 8.2, 7.4, 31.2, 12.9, 17.3 so the front coupled axle is taking nearly half the loco's weight on its own! and the driving axle is not taking much at all. I had been advised that the B1 could do with up to 10kg added to the rear of the loco to achieve reasonable balance, at this point I just tried adding weight using some big bits of steel bar (3 1/2" Dia and 4" dia) sitting on the footplate, total 8kg. Axle loading changed but not what I thought - 6.0, 6.0, 31.45, 18.0, 25.05 The front coupled axle was still carrying too much weight. Back to the drawing board and I changed all the D&C axle springs back to the original ones that were fitted when I got the loco, part of my previous experiments being to uprate the front axle springs and the driving axle ones so I had ended up with three different spring rates on the loco, probably in hindsight not a good move. I tightened all the springs to maximum compression governed by the length of thread available on the spring pins, which looking at them seem to all have the same length threads. This made a dramatic difference now the figures were 10.2, 9.15, 18.9, 21, 17.05 so weight distribution across the D&C axles is more even but not as good as I am hoping for. I made some further adjustments but won't bore you with all the numbers yet, I removed some compression off the rear set, that didn't help. Then I adjusted the bogie springs compression first increasing then decreasing a bit less and finally removed one turn of compression off the front D&C axles. Lastly I added 3.75kg weight back onto the footplate. The final results (average of a number of measurements) 10.20, 9.85, 18.4, 20.5, 20.5. I think I have now got it much closer to where I want it to be, the D&C axles are taking pretty much the same weight as each other and hopefully with a bit more adjustment of the bogie springs I can increase the load on the front D&C axle and take a bit off the bogie. Here are a couple of graphs which hopefully shows the progress to the final results, I have combined both bogie axles for clarity. C1 = front coupled axle, D = driving axle, C2 = rear coupled axle: The top line is the total weight of all axles, the obvious peaks are where the extra weight has been added. It does clearly show how the weights on each axle started all over the place and have now come much closer together.  This is the same data just shown as a stacked bar graph, again the last bar shows each coloured segment to be very nearly the same which is what I have been aiming for in the absence of any other information.  My problem now is how to add nearly 4kg weight to the very back of the loco as it is all built so not much chance of making things heavier to compensate. I am thinking maybe a new cab from 1/4" plate? or probably more easy is to make a thick footplate anything up to 3/4", could be in smaller sections to make fitting easier? I am in the process of freeing up some space between the frames under the footplate by removing the hydrostatic lubrication as the tank is located there, I could then make a brass or steel box and fill with lead to drop down below the footplate. Any way this is just the first stab at the ideas and I won't know if this has made the improvement I am looking for until I can get back on the track with it. Hope it is of some interest Chris D |
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Post by Roger on Mar 20, 2021 0:11:47 GMT
Hi Chris,
Something doesn't make sense if I understand what you're saying. The total weight of the locomotive is obviously the sum of all of the individual wheel loadings. Changing the springs can't change the total weight, but that's what appears to happen. Are those readings for each axle ie a single reading being for one axle? Surely you want to know the weight on each wheel? Maybe I'm not reading that right.
I get a total of 77Kg, 86.5Kg and 76.3Kg for the three sets of readings in the text, so something literally doesn't add up.
The stiffer the springs, the more difference you'll see if the track isn't perfectly level.
I've made a massive stretcher that fits under the Cab and Bunker which I think is 25mm thick. Can you do something like that? Obviously Steel isn't as heavy as Lead, but it might be easier to fit a big piece that you attach other things to.
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Mar 20, 2021 1:40:19 GMT
Hi Chris, Something doesn't make sense if I understand what you're saying. The total weight of the locomotive is obviously the sum of all of the individual wheel loadings. Changing the springs can't change the total weight, but that's what appears to happen. Are those readings for each axle ie a single reading being for one axle? Surely you want to know the weight on each wheel? Maybe I'm not reading that right. I get a total of 77Kg, 86.5Kg and 76.3Kg for the three sets of readings in the text, so something literally doesn't add up. The stiffer the springs, the more difference you'll see if the track isn't perfectly level. I've made a massive stretcher that fits under the Cab and Bunker which I think is 25mm thick. Can you do something like that? Obviously Steel isn't as heavy as Lead, but it might be easier to fit a big piece that you attach other things to. Hi both I was reading quite recently that in full-size it was impossible to measure axle loadings without the readings being affected to some extent by the axles either side. This will probably account for the totals not adding up. Also somebody on this forum has told us about having to roll the locos to and fro because 'stiction' in the horns meant that it was unlikely you would get the same result twice, so again this could influence the total, but maybe not so much. Of course in full-size, axle loadings were critical on the heavier locos, so it was essential to make the effort. In miniature the argument seems less -er- pressing, though some people take it very seriously. Personally I'm happy if I can get the engine level port and starboard and both buffer beams to the same height! Gary |
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Post by Roger on Mar 20, 2021 8:47:26 GMT
Hi Chris, Something doesn't make sense if I understand what you're saying. The total weight of the locomotive is obviously the sum of all of the individual wheel loadings. Changing the springs can't change the total weight, but that's what appears to happen. Are those readings for each axle ie a single reading being for one axle? Surely you want to know the weight on each wheel? Maybe I'm not reading that right. I get a total of 77Kg, 86.5Kg and 76.3Kg for the three sets of readings in the text, so something literally doesn't add up. The stiffer the springs, the more difference you'll see if the track isn't perfectly level. I've made a massive stretcher that fits under the Cab and Bunker which I think is 25mm thick. Can you do something like that? Obviously Steel isn't as heavy as Lead, but it might be easier to fit a big piece that you attach other things to. Hi both I was reading quite recently that in full-size it was impossible to measure axle loadings without the readings being affected to some extent by the axles either side. This will probably account for the totals not adding up. Also somebody on this forum has told us about having to roll the locos to and fro because 'stiction' in the horns meant that it was unlikely you would get the same result twice, so again this could influence the total, but maybe not so much. Of course in full-size, axle loadings were critical on the heavier locos, so it was essential to make the effort. In miniature the argument seems less -er- pressing, though some people take it very seriously. Personally I'm happy if I can get the engine level port and starboard and both buffer beams to the same height! Gary Hi Gary, I think this is absolutely true, and it's one reason why I made my setup so I can read off the weight being carried by each wheel at the same time. It gives you a much better feel of what's going on, and it saves a lot of faffing about moving from axle to axle. You do see stiction playing a part, but it always shows the correct total of course. It's interesting to watch the interplay of one wheel to the other as you rock the loco about. We put several of the locomotives on it when we had a private run, and you'd be staggered at how far out most of them were. |
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Post by Deleted on Mar 20, 2021 9:26:30 GMT
[/quote]Hi both I was reading quite recently that in full-size it was impossible to measure axle loadings without the readings being affected to some extent by the axles either side. This will probably account for the totals not adding up. Also somebody on this forum has told us about having to roll the locos to and fro because 'stiction' in the horns meant that it was unlikely you would get the same result twice, so again this could influence the total, but maybe not so much. Of course in full-size, axle loadings were critical on the heavier locos, so it was essential to make the effort. In miniature the argument seems less -er- pressing, though some people take it very seriously. Personally I'm happy if I can get the engine level port and starboard and both buffer beams to the same height! Gary[/quote] Hi Gary You may be reffering to me quoting the procedure that's given in ' LNER Workshops' and also that was passed on to me by those who were part of 4472's crew and have experience in weighing locomotives. From what I recall setting weights involved moving the loco a number of times to settle the springs as best they could and weigh again. I was told that even after doing this things were likely to change soon after running on the rails again so they were never 'spot on' for long. Roger, Re 'weighing individual axles' I think you'll find that Chris's setup is very capable of doing this although personally I wouldn't look at this until I had the axles where they should be first. Luckily I know exactly what the axle split is percentage wise of my prototype and can use that as a guide. I note a comment in the book I mentioned above of when fitting the improved weighbridge design at Doncaster in 1935 that it was more accurate as it could measure each wheel. Perhaps in earlier days they weren't so fussy when weighing locomotives? Anyway, well done Chris, an interesting exercise, it will be some years yet before I can do the same with 4472 but each day spent in the workshop gets me closer...  Pete |
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Post by coniston on Mar 20, 2021 10:02:59 GMT
Hi Chris, Something doesn't make sense if I understand what you're saying. The total weight of the locomotive is obviously the sum of all of the individual wheel loadings. Changing the springs can't change the total weight, but that's what appears to happen. Are those readings for each axle ie a single reading being for one axle? Surely you want to know the weight on each wheel? Maybe I'm not reading that right. I get a total of 77Kg, 86.5Kg and 76.3Kg for the three sets of readings in the text, so something literally doesn't add up. The stiffer the springs, the more difference you'll see if the track isn't perfectly level. I've made a massive stretcher that fits under the Cab and Bunker which I think is 25mm thick. Can you do something like that? Obviously Steel isn't as heavy as Lead, but it might be easier to fit a big piece that you attach other things to. Hi Roger, thanks for your interest and comments, the increase in weight from 77 to 86.5Kg is due to the addition of the pieces of 3 1/2" and 4" Dia steel bar placed on the footplate. the difference between 77 and 76.3 is within the tolerance of the weighing system and methods. I haven't gone as far as weighing each wheel which I can do as the wheel tread rides up on a thin spacer so removing one side means only one wheel is registering on the scale. I will get to do that after I have sorted how to add the weight. If I was making the loco I would incorporate something like your massive stretcher, but at the moment between the frames under the footplate is the steam brake cylinder, injector feed pipes and soon to be removed the hydrostatic oil tank. Martin Evans design feeds water into two check valves at the bottom of the back head, not a good idea but I cannot change that now, so not possible to free up that space as much as I would like. Anyway I have to sort the mechanical lubricators first before seeing what space is available for the additional weight. Chris D |
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Post by coniston on Mar 20, 2021 10:13:58 GMT
Hi both I was reading quite recently that in full-size it was impossible to measure axle loadings without the readings being affected to some extent by the axles either side. This will probably account for the totals not adding up. Also somebody on this forum has told us about having to roll the locos to and fro because 'stiction' in the horns meant that it was unlikely you would get the same result twice, so again this could influence the total, but maybe not so much. Of course in full-size, axle loadings were critical on the heavier locos, so it was essential to make the effort. In miniature the argument seems less -er- pressing, though some people take it very seriously. Personally I'm happy if I can get the engine level port and starboard and both buffer beams to the same height! Gary Hi Gary, thanks for your comments, yes as Pete says he mentioned the problems of full size in his thread. I agree getting the loco level all round is a good aim and somewhat easier with a short six coupled loco like the 1500 or my own Super Simplex. Knowing he B1 suffers from being front heavy, I believe also a trait in full size, I am trying to even the loading on each axel as even as possible and maybe later on each wheel as well. I have excellent comparisons in the club as there are two other Martin Evans B1's which both perform well when passenger hauling pulling three carriages where as mine struggled with adhesion with the same load so that is my starting point. When we are able to we will get all three B1's together and do a weighing exercise on them to see if we can all learn something (or not). I would like to run it in IMLEC maybe this year or next but before then I need to get the best adhesion I can, not only for this but for general passenger hauling. Chris D |
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dscott
Elder Statesman
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Post by dscott on Mar 21, 2021 3:11:30 GMT
 On my version of Asia. For mine these days I am reverting to big lumps just under the footplate. In fact I am pondering inscribing floorboards into the top which is useful when something alight drops onto it. Almost killed the Milling Machine making it. Yesterday I cut out the bit for the back 1/2" by 1/2" that holds the rear Buffer Beam in place. David and Lily. |
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Post by Roger on Mar 21, 2021 9:19:47 GMT
Of course in full-size, axle loadings were critical on the heavier locos, so it was essential to make the effort. In miniature the argument seems less -er- pressing, though some people take it very seriously. Personally I'm happy if I can get the engine level port and starboard and both buffer beams to the same height! Gary Hi Gary, I wouldn't underestimate the effect of uneven loading in each wheel on miniature locomotives. It's been clearly demonstrated that soft springing makes a big difference to the amount of grip available. Regardless of the springing, the wheel with the lightest loading will give up first and cause a cascade of slipping. The closer they are to each other, the higher the overall adhesion will be. In these times where more and more tracks are sadly going over to Aluminium rails, getting as much adhesion as possible seems to me to be more important than ever. In the end, either you measure it or you don't. If you do, then you may as well go for the best possible setup. If you don't measure it, you have absolutely no idea what's going on, and from my measurements, it's not uncommon for some wheels to be carrying twice the load that others do. That has to have a negative impact on the locomotive's pulling power. Maybe on very large locomotives that's not an issue, but for small ones I suspect that it is. |
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Post by ejparrott on Mar 21, 2021 19:47:54 GMT
Lead and carbide are your friend. Last thing I would do is make a cab from 1/4" plate. With our Netta we added some detail to the cab in the form of the false wooden floor and the two side seat boxes. In these we hid 6Kg of scrap carbide glued together with lead poured in.
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Post by ejparrott on Mar 21, 2021 19:48:38 GMT
duplicate post
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Post by coniston on Mar 21, 2021 22:42:11 GMT
Lead and carbide are your friend. Last thing I would do is make a cab from 1/4" plate. With our Netta we added some detail to the cab in the form of the false wooden floor and the two side seat boxes. In these we hid 6Kg of scrap carbide glued together with lead poured in. Thanks Ed, you've just talked yourself out of a job there, would have been laser cut  I will look into a false footplate and seat boxes but as you see below there's a lot of pipework that needs to move to make room for some simple pieces. Sight feeds are going as changing to mechanical lubricators as is the condensing coil. Then I need to reposition the axle box lubricators and finally (if I can do it easily) move the injector steam pipes each side. This will make the whole area much clearer to get a thick floor and some seat boxes in there.  Below the footplate is the hydrostatic oil tank which is going but it still leaves the steam brake cylinder to go back in if only to stop the brakes moving unintentionally. Also in there is the injector feed pipes to the check valves low down on the back head. So all pretty congested and would be so much easier if adding this to a new build.  Chris D |
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Post by Roger on Mar 21, 2021 23:46:52 GMT
I see the problem now, there's not much room there to add anything substantial.
One thing that I've heard being done is to let the tender add some weight to the back of the locomotive by leaving out or using light springs on the front of the tender and adding weight there. Obviously the coupling has to be made in such a way as to transfer the load.
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dscott
Elder Statesman
Posts: 2,440
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Post by dscott on Mar 22, 2021 0:01:40 GMT
 WEIGHT! Yes one thing you realize with the modern batches of model Locomotives is the shear weight of them. Above a lovely Big Prairie Tank in O Gauge is the same weight as a BRICK. Slow moving and superbly detailed. Roger is quite right with the weight from the tender idea. Pendon Museum and Guy Williams perfected this especially on Dukes and Bulldogs. Improving their pulling power enormously. Shame it does not extend to Humans where a bit of weight does not improve Pulling Power! Getting Coat. David and Lily. |
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baldric
E-xcellent poster
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Post by baldric on Mar 22, 2021 9:02:54 GMT
I see the problem now, there's not much room there to add anything substantial. One thing that I've heard being done is to let the tender add some weight to the back of the locomotive by leaving out or using light springs on the front of the tender and adding weight there. Obviously the coupling has to be made in such a way as to transfer the load. Won't that lead to there being an increased risk of the tender de-railing as there is no weight on the leading wheel-set to keep it on the rails? I know that no weight on a wheel has been an issue in full-size leading to a tender de-railing. Baldric. |
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Post by Roger on Mar 22, 2021 9:12:53 GMT
I see the problem now, there's not much room there to add anything substantial. One thing that I've heard being done is to let the tender add some weight to the back of the locomotive by leaving out or using light springs on the front of the tender and adding weight there. Obviously the coupling has to be made in such a way as to transfer the load. Won't that lead to there being an increased risk of the tender de-railing as there is no weight on the leading wheel-set to keep it on the rails? I know that no weight on a wheel has been an issue in full-size leading to a tender de-railing. Baldric. It doesn't appear to be a problem, but you'd have to dig deeper and find people who have done it to get a definitive answer. |
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Post by Deleted on Mar 22, 2021 9:53:21 GMT
I can say from experience that I once put too much of my weight on the rear of 4470's tender resulting in the tender derailing...when I say weight, I mean my big lump leaning too far forward... oh and the fact that I was on a 5" driving trolley with a 3 1/2" loco... not a good idea when leaning on it... Pete |
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kipford
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Building a Don Young 5" Gauge Aspinall Class 27
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Post by kipford on Mar 22, 2021 12:59:16 GMT
Chris
Why are you changing over to mechanical lubrication, I do not recall you having issues? Also do not bin your redundant hydrostatic system it may be suitable for the Aspinall (obviously beer vouchers would be available) and would save me making one!
Dave
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Post by coniston on Mar 22, 2021 13:37:18 GMT
Chris Why are you changing over to mechanical lubrication, I do not recall you having issues? Also do not bin your redundant hydrostatic system it may be suitable for the Aspinall (obviously beer vouchers would be available) and would save me making one! Dave Hi Dave, only moving back to mechanical to free some space below the footplate, no other reason and sorry but the hydrostatic will be used on the Pansy or Grange Chris |
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Post by coniston on Mar 22, 2021 13:39:10 GMT
I see the problem now, there's not much room there to add anything substantial. One thing that I've heard being done is to let the tender add some weight to the back of the locomotive by leaving out or using light springs on the front of the tender and adding weight there. Obviously the coupling has to be made in such a way as to transfer the load. I think this is certainly something to look into if adding the weight to the loco is not as practical as I am hoping for. I have also been told that leaning on teh front of the tender would also give the same effect but I'd much rather not have to do that. Chris D |
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