RMweb Gold Stubby47 Posted October 17, 2015 Author RMweb Gold Share Posted October 17, 2015 Now the wheels have arrived, and with the 1:35 scale figure purchased today, I've resized the loco drawing and started to make a card mockup of the loco. This will allow me to work out where the motor might fit. Link to post Share on other sites More sharing options...
RMweb Gold Stubby47 Posted October 18, 2015 Author RMweb Gold Share Posted October 18, 2015 I have been thinking about the use of SPDT reed switches and am now partially convinced they won't work.... The problem will be in the trailing axle, which should always be +'ve, being in contact with the section of rail which has defaulted to the -'ve state, thus causing a short. I need to prove / disprove this, but am fairly convinced it will fail. So, the next plan is two sets of SPST ( on/off) reeds, either side of the track. These will have to be wide enough apart so they are not affected by the 'wrong' magnets. Hmmmmm..... Link to post Share on other sites More sharing options...
peter220950 Posted October 18, 2015 Share Posted October 18, 2015 Yes, I think I see your point, the magnets being at the front of the section cause the problem, and they need to be there to make it work on the current scheme. I took a look back through all of the earlier posts and picked up on my previous post re putting the magnets at the back, and had a bit of a think. What happpens if you change the switching to the back of the section, immediately after a rail break, if you put the magnets in the coach, and changed polarity of the rear section only, the problem might go away? - There being nothing following there's no problem with how long it takes for the section to clear. It will need some magnets under the footplate, but moving the switches means you can start to switch immediately behind the front drivers. Forgive the poor hack of your drawing, but I hope you can see what I mean. Is there a fundamental flaw in my logic? Can't see it at the moment, but I've spent the last couple of weeks thinking the original scheme was ok, so what do I know Peter Link to post Share on other sites More sharing options...
RMweb Gold Stubby47 Posted October 18, 2015 Author RMweb Gold Share Posted October 18, 2015 Peter, Thanks for that. Your earlier suggestion was in my mind, but I was placing the magnets before the next section. Having them at the end of the current section with an elongated magnet does seem to be a viable solution. I need to cut a paper loco/coach template and try it moving along a simulated track, but this does look good. Also, as you said, putting the magnet under the coach is a whole lot easier. Link to post Share on other sites More sharing options...
RMweb Premium Ian Smeeton Posted October 18, 2015 RMweb Premium Share Posted October 18, 2015 Do all three of the loco's drivers need to be live? For better current collection,possibly, but the rear one could be electrically 'dead' to give more space between the loco and the coach. Regards Ian Link to post Share on other sites More sharing options...
RMweb Gold Stubby47 Posted October 18, 2015 Author RMweb Gold Share Posted October 18, 2015 Hi Ian, On the prototype the middle divers are flangless. On the model , as the chassis won't be compensated, I'm going to use the middle driver as the geared wheel, so it won't drive at all. It will be hidden by being so far under the body. This means, of course, the outer two wheels need to be used for current collection. Stu Link to post Share on other sites More sharing options...
RMweb Gold Stubby47 Posted October 22, 2015 Author RMweb Gold Share Posted October 22, 2015 As the loco chassis will need soldering, and I'm not sure my workplace would appreciate my using a hot iron, I've made a start on the coach. This is using sheet and strip bass wood. The main walls Some more framing added The main walls stuck to the baseplate Link to post Share on other sites More sharing options...
DonB Posted October 23, 2015 Share Posted October 23, 2015 I have been thinking about the use of SPDT reed switches and am now partially convinced they won't work.... The problem will be in the trailing axle, which should always be +'ve, being in contact with the section of rail which has defaulted to the -'ve state, thus causing a short. I need to prove / disprove this, but am fairly convinced it will fail. So, the next plan is two sets of SPST ( on/off) reeds, either side of the track. These will have to be wide enough apart so they are not affected by the 'wrong' magnets. Hmmmmm..... Hi, Stu. A late response to your problems with magnets and reed switches. I've had opportunity to discuss this problem with a qualified electronics electrician who visited us this week. He proposes a solution which dispenses with the need for magnets and reed switches, but at the expense of insulating the wheels from the chassis. (I should emphasize that he has never had any involvement with owning, building or operating a model railway!! so it took a while to explain the concept, and why anyone would want to do this! I think he may subscribe to the straight-jacket school!) He proposes that the magnets and reed switches be substituted by a diode array in the form of a couple of Wheatstone bridges, and that the alternate rail sections will always be connected, positive - negative - positive - negative etc. Now that the guests have gone, I will redraw, hopefully legibly and logically, the sketches and notes he / we made and post them here in the next few hours for your consideration. Edit:- Transferred this thought to other thread... Link to post Share on other sites More sharing options...
RMweb Gold Stubby47 Posted October 31, 2015 Author RMweb Gold Share Posted October 31, 2015 Today, I shall be mostly making a loco chassis. I have the brass for the frames, brass for the cross members, wheels, axles, motor & worm gear. I don't have the connecting rods or pistons yet, but do have ideas on how these can be fabricated. Link to post Share on other sites More sharing options...
N15class Posted October 31, 2015 Share Posted October 31, 2015 Good luck, dont forget we want to see the progress. Link to post Share on other sites More sharing options...
RMweb Gold Stubby47 Posted October 31, 2015 Author RMweb Gold Share Posted October 31, 2015 Progress, yeah, er, hmmm. Today has been a learning curve : Brass is harder to cut than plasticard Brass is harder to solder than plasticard is to glue Brass is harder to drill holes in Holes for chassis need to be in the right place Chassis frames need to be held together for drilling with more than a small piece of solder So all good, informative stuff. I need to re-think my strategy, but it's not difficult, just different. Link to post Share on other sites More sharing options...
N15class Posted October 31, 2015 Share Posted October 31, 2015 Progress, yeah, er, hmmm. Today has been a learning curve : Brass is harder to cut than plasticard Brass is harder to solder than plasticard is to glue Brass is harder to drill holes in Holes for chassis need to be in the right place Chassis frames need to be held together for drilling with more than a small piece of solder So all good, informative stuff. I need to re-think my strategy, but it's not difficult, just different. I have it the other way around Plasticard does not do things that brass does, and boy does it smell when you solder it. Link to post Share on other sites More sharing options...
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