gordon s Posted February 25, 2016 Author Share Posted February 25, 2016 Just got back from a family funeral in the Isle of Wight. A sad day all round, but a lovely send off for a good friend from my wife's family.... Golfing tomorrow at Remedy Oak, so a very quick reply. Thanks for all your ideas. I'm flattered that you take the time to think all these things through. I'll be glad to get some track down soon and finally see something move. I will consider all your suggestions over the weekend and hopefully will be able to give you my thoughts once the current commitments give me a break. Martin, just a quick spoiler before I go to bed. I like your idea but that would mean dumping or selling Alan Downes station building as the main building has to go at the side. The spacing of the platforms etc have all been set to accommodate the overhead footbridge etc which is part of the station building. It has to be this way......or eBay.... 6 Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted February 26, 2016 RMweb Gold Share Posted February 26, 2016 Martin, just a quick spoiler before I go to bed. I like your idea but that would mean dumping or selling Alan Downes station building as the main building has to go at the side. Hi Gordon, Well obviously you mustn't dispose of such a fine model. But it does have the look of a through station rather than a terminus. Perhaps the "back story" could be that the line originally did, or was intended to, continue on beyond the buffers to somewhere else? The presence of a footbridge doesn't necessarily mean you can't have a concourse at the buffers -- much easier than lifts for luggage barrows, and I don't see any evidence of lift headgear in the roof profiles. It is surely too grand a station for a simple barrow crossing at the bottom of the platform ramps? regards, Martin. 1 Link to post Share on other sites More sharing options...
RMweb Premium polybear Posted February 26, 2016 RMweb Premium Share Posted February 26, 2016 I like your idea but that would mean dumping or selling Alan Downes station building as the main building has to go at the side. It has to be this way......or eBay.... Sorry to disagree with Martin, but personally I don't think any of the buildings you've shown recently are suited to Eastwood Town. Absolutely, definitely not. And dumping them would be a very antisocial thing to do. Ebay? Tacky site, that one - full of chancers. Don't worry though, I happen to know a little cute fluffy cub that'll be only to pleased to help you out in disposing of them. Oh yes.... Link to post Share on other sites More sharing options...
RMweb Gold Brinkly Posted February 26, 2016 RMweb Gold Share Posted February 26, 2016 Sorry to hear of your loss. Such a nice building Gordon. My girlfriend said it must have taken a while for Alan to build. Can't wait to see it in place. Kind regards, Nick Link to post Share on other sites More sharing options...
hayfield Posted February 28, 2016 Share Posted February 28, 2016 Just got back from a family funeral in the Isle of Wight. A sad day all round, but a lovely send off for a good friend from my wife's family.... Golfing tomorrow at Remedy Oak, so a very quick reply. Thanks for all your ideas. I'm flattered that you take the time to think all these things through. I'll be glad to get some track down soon and finally see something move. I will consider all your suggestions over the weekend and hopefully will be able to give you my thoughts once the current commitments give me a break. Martin, just a quick spoiler before I go to bed. I like your idea but that would mean dumping or selling Alan Downes station building as the main building has to go at the side. The spacing of the platforms etc have all been set to accommodate the overhead footbridge etc which is part of the station building. It has to be this way......or eBay.... IMG_5925.jpg It would be a great shame not to use the model, is there any way it could be converted into a terminus. Could a new rear be made to replace the un-modelled side?. There might be offers from some if you don't fancy doing it, or a revised plan for the terminus end using the existing models Link to post Share on other sites More sharing options...
gordon s Posted February 29, 2016 Author Share Posted February 29, 2016 (edited) Morning all. Been trying to get my head round gradients and curves as discussed earlier in the thread. Here is an illustration of what I'm talking about... Here's a track bed of 140mm width between A & B. To keep things simple, I have a 1:100 gradient and I want to rise 100mm, so that will need a track length of 10m. On a 10m length of dead straight track, A & B will remain parallel to the datum line. That's fine and in our discussion pointwork on that gradient shouldn't be a problem. The bit that is confusing me is once you change from straight track to a spiral. Even though the trackbed is in a spiral, points A & B always remain parallel to the datum, so my head says the trackbed is flat across A & B. Having been down this route before, I can appreciate that on double track the length of the inner track will be shorter than that on the outer and as such the gradient will increase even though they are on the same piece of trackbed. That is a simple function of the length of the track versus the overall height gain. OK, now we have an A4 with a wheelbase of 60' or 240mm in 00 gauge. I can understand that the front of the wheelbase on a 1:100 gradient will be 2.4mm higher than the rear of the wheelbase, but if the points A & B always remain parallel to the datum, then surely that's no different to a straight gradient? I've taken a 00-SF curved turnout and placed it on a 1:100 gradient on a 1m radius curve and can't determine any rock whatsoever on the chassis. All wheels appear to be in contact with the rails and as such I'm not sure I understand the problem. I totally accept this is not a precise test using calibrated measuring equipment and may still have egg on my face, but can we just discuss this for a few minutes in simple terms before I plough ahead? I’ve trawled the web to find a simple diagram to illustrate the potential problem, but can’t find anything clear and concise. I'm not doubting what you say Martin, simply I would like to explore this subject further so that I can understand it clearly. This could be an issue for me as I now have some measurements re how much space I'm going to need to construct the gradient needed to clear the platform ends in ET terminus. At point A on the right hand side, there has to be 70mm clearance plus the thickness of the trackbed at 12mm, meaning a rise of 82mm. Starting from point A an 82mm rise at point B would mean a gradient of 1:70. At point C, it is 1:85 and at point D it is 1:102. My preferred end of gradient is point D or beyond and that's what I originally set out to do. If it really is a problem, then I can simply shorten the ends of the platforms and tracks and then disguise the gradient tracks. It wouldn't be difficult to do, but I would prefer not to unless there is an issue with pointwork on a curve/gradient. Thanks for your understanding guys. It's important to me not to go up a blind alley, so would rather spend a little time now than waste time, effort and materials on something that may not work. Edited February 29, 2016 by gordon s 1 Link to post Share on other sites More sharing options...
gordon s Posted February 29, 2016 Author Share Posted February 29, 2016 Sat in the bath for 15 minutes or so and may have had a Eureka moment... A 3' radius curve is 914.4mm radius. The circumference of a circle is (914.4 x 2) x pi = 5746mm. Of course this is on the centre line, so taking each rail you get these figures. Outer. 914.4 + 8.25 = 922.65 x 2 = 1845.3 x pi = 5797.9. Inner. 914.4 - 8.25 = 906.15 x 2 = 1812.3 x pi = 5694.2. The difference in gradient from 1:100 is just 1:100.9 for the outer rail and 1:99 for the outer. The difference in rail length over a full circle is 103mm. Looking at an A4, the driving wheels were on 6'6" so that represents a wheelbase over the six driving wheels of 52mm. I have discounted the front bogie and the Cartazzi truck as they are free to move vertically. The proportion of 52mm to 5746mm is 1/110.5, so the overall difference in rail length between the inner and outer over that 52mm length is just 103/110 or 0.94mm. What that represents in difference in height between the inner and outer rail is beyond me. The unknown is how much that height difference will be and whether or not that would be sufficient to break electrical contact across a fixed chassis with pick ups on all wheels. Feel free to pick holes in my schoolboy maths...... 1 Link to post Share on other sites More sharing options...
RMweb Premium 47137 Posted February 29, 2016 RMweb Premium Share Posted February 29, 2016 This is what I did. Set up a quadrant of Setrack on a sheet of board on the floor. Lift one side of the board, so one end of the track stays flat on the floor, pointing down to the floor. When you look at the other end of the track, it has a cross-fall (superelevation) on it, which on a real model railway you need to get rid of. This cross-fall equals the gradient at the bottom of the track, and also equals the slope on the board. So in a 90 degree bend, you have got to impart a twist which equals the overall vertical climb. With your generous curves and a 1:100 gradient, this will be ever so small - if the cross-members are at right angles to the track, the flex in the plywood track bed will take it up as you fix it down to the cross-members. If you have a wye turnout on the gradient, the maths will tell you the crossing vee ought to be higher than the two stock rails. Keep the turnout flat, and the track beyond it flat for the length of a loco, and lose the error in the next yard or so of track. The differences in rail lengths will be too small to worry about. Even on the Thread Shed (4-inch curves), the inner rail was barely 2 inches longer than the outer one. Hope this helps! - Richard. Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted February 29, 2016 RMweb Gold Share Posted February 29, 2016 (edited) Hi Gordon, Your 13ft wheelbase is rather less than for many locomotives. For example this GWR 2-8-0T locomotive has a fixed wheelbase of 20ft: http://www.greatwestern.org.uk/drawings/loco/loco161.jpg From: http://www.greatwestern.org.uk/loco_draw.htm Here I have used the dummy vehicle tool in Templot to represent a fixed wheelbase of 19ft-8in (for convenience so that it matches the sleeper centres): It is on 36" radius 00-SF, rising from left to right. On a perfect helix, the sleepers will always be level along their centre-lines. You can see therefore that the wheel at A will be a fraction further up the gradient (higher) than the wheel at B. And likewise the wheel at C is a fraction further up the gradient (higher) than the wheel at D. The result is that the loco will be sitting on the rails along a line from A to C and rocking to and fro at B and D. Not by very much on a gradient of 1:100, but maybe just sufficient to mean that the wheels at B and D are unloaded and not in firm contact with the rail. The problem is that when climbing the gradient, wheel D is the very wheel which is doing most of the work in guiding the locomotive round the curve. If it is not in firm contact with the rail, there is at least the possibility that it will climb over the rail and derail, especially while negotiating pointwork. With such a gentle gradient, and an easy curve (in 00 terms), and most vehicles having a shorter fixed wheelbase than this, the effect is going to be very slight. It could be eliminated entirely by having vehicles with a sprung or compensated suspension, but I don't know to what extent that applies to your RTR models. Nevertheless, if it was my railway I would not install pointwork on a curved gradient as sharply curved as this. Apart from the above derailment risk, there is also the difficulty of getting the switch blades to sit properly on the slide chairs and move without binding. You may find in tests that my fears are unfounded. But I would drop the level of the terminus, and/or increase the gradient, so that the summit of the bank can be out beyond the curved station throat, with the entire station on the level. (There being no obvious means to ease the radius). The only thing preventing dropping the terminus is the height conflict with the purple tracks below the platform buffers, so it would seem sensible to shorten the station sufficiently to avoid that. (On the prototype such a curve would have some cant (superelevation), if on a running line where speeds are much higher than on the approach to a terminus. But it is still not possible to make an unsprung fixed wheelbase sit firm on the rails.) (You can also see in the diagram the amount of side-play needed on the inner axles to keep the wheels inside the rails. You can use this method in Templot to measure the amount of axle side-play needed.) regards, Martin. Edited February 29, 2016 by martin_wynne Link to post Share on other sites More sharing options...
RMweb Premium Chimer Posted February 29, 2016 RMweb Premium Share Posted February 29, 2016 I can't get my head round the maths, or whether this will help, but to see the flaw in your orginal logic about the trackbed being flat .... Imagine you mark a 180 degree curve trackbed out on a flat piece of ply and put in on a flat surface. Call one end of the curve A, the other B. Now raise point B - the whole piece of ply is going to be slanted from A to B, so the inner edge of the trackbed is going to be higher than the outer edge at A, and lower at B. If you now cut the trackbed out from the sheet of ply, you will be able to force it to be level at both ends, but only at the cost of putting a twist in the ply. You can also force it to be level at any intermediate support point. If you do this at an infinite number of intermediate points, it might appear that you can make it level throughout the turn - but I suspect (my maths runs out at this point) this would require the infinite number of individual supports to have zero thickness, which may be asking too much of even your amazing carpentry skills. If I've completely missed the point, I apologise unreservedly! Cheers Chris Link to post Share on other sites More sharing options...
G.M.R. Posted February 29, 2016 Share Posted February 29, 2016 If it helps, I have a number of curves on inclines. Much steeper and sharper than yours. I have used Woodland Scenics poly inclines throughout. These keep my track bed flat at all times. I even manage to handle two tracks side by side with a bit of squeezing of the poly. I also have a couple of curved points on an incline. I have no problems runnning any of my 00 stock. In my experience the most important part to get right with an incline is the top and bottom. I have found it necessary to ease the incline out with a vertical curve. The top has been the hardest to get perfect. 1 Link to post Share on other sites More sharing options...
gordon s Posted February 29, 2016 Author Share Posted February 29, 2016 Hi guys, thanks for your info. Sadly ET will now go on hold. I've been struggling with my own health for a few weeks. My temp is up to 39.2 and it may be I have contracted C DIFF for the third time. I cannot keep anything down and I have pain in my kidneys and liver. It was touch and go that I went to hospital tonight, but I have to be isolated and it's probable no beds were available. Hopefully I'll be back soon, particularly as we just cremated my wife's first husband a week ago. As you can imagine she is pretty stressed right now..... Link to post Share on other sites More sharing options...
dseagull Posted February 29, 2016 Share Posted February 29, 2016 Best wishes Gordon, the layout will always be there to come back to once the CME is back on his feet. Link to post Share on other sites More sharing options...
Andrew P Posted February 29, 2016 Share Posted February 29, 2016 All the very best Gordon, and I hope to see you back here, fit and well again soon, your a real inspiration. Link to post Share on other sites More sharing options...
Guest bri.s Posted February 29, 2016 Share Posted February 29, 2016 Best wishes, hope to see you back fit and well and you can get back to modelling again Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted February 29, 2016 RMweb Premium Share Posted February 29, 2016 Get well soon Gordon, the trainset and cross country hockey will await your return too good health. Link to post Share on other sites More sharing options...
RMweb Gold PhilH Posted February 29, 2016 RMweb Gold Share Posted February 29, 2016 Not so good Gordon...hope you perk up soon, not only for yourself but for the workout this thread gives my ageing brain! Link to post Share on other sites More sharing options...
sp1 Posted February 29, 2016 Share Posted February 29, 2016 Get well soon Gordon Link to post Share on other sites More sharing options...
jukebox Posted February 29, 2016 Share Posted February 29, 2016 All the best Gordon - hope you get well soon. Link to post Share on other sites More sharing options...
RMweb Premium 45156 Posted March 1, 2016 RMweb Premium Share Posted March 1, 2016 Best wishes for a speedy recovery Gordon. Link to post Share on other sites More sharing options...
trisonic Posted March 1, 2016 Share Posted March 1, 2016 Ouch. Please get well soon, G. Pete. Link to post Share on other sites More sharing options...
92220 Posted March 1, 2016 Share Posted March 1, 2016 Very best wishes for a rapid recovery, Gordon. Thinking of you. Iain Link to post Share on other sites More sharing options...
RMweb Gold Rowsley17D Posted March 1, 2016 RMweb Gold Share Posted March 1, 2016 Wishing you all the best for a speedy recovery, Gordon. Given your 350+ followers the next few pages could become quite repetitive, but I'm sure each message is quite heartfelt. Link to post Share on other sites More sharing options...
islandbridgejct Posted March 1, 2016 Share Posted March 1, 2016 Yes, hope you get well soon. Link to post Share on other sites More sharing options...
RMweb Gold fishytrains Posted March 1, 2016 RMweb Gold Share Posted March 1, 2016 Hope the lay off is not too long and you make a speedy and full recovery. Mike Link to post Share on other sites More sharing options...
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