Ch4lkst3r Posted December 29, 2015 Share Posted December 29, 2015 Hi, I'm slowly laying all the track on my layout and I have a electrofrog finescale (code 55) double slip wired as it should be with the point motor for the one side controlling the frog polarity for the other side. I have tested it all with a Dapol Hymek during laying the track and all is working fine and there are no shorts being experienced. I have finally got round to putting decoders in my Farish Midland Pullman and this is fine in a straight line but if I try to use the double slip to crossover I'm experiencing a short and the layout shuts down. On close examination I think that the issue is due to the wheelsets touching the opposite rail where it joins the frog (i.e. in the V). I temporarily put some tape over the inside of the rail and it doesn't short. Has anyone else experienced a similar problem? Comparing the wheelsets of the Hymek to the Pullman the back to back of the Hymek it greater than that of the Pullman. I'm thinking of applying some paint to the side of the rail at the point I believe it is shorting to prevent electrical contact or does anyone have other suggestions? Regards, Iain Link to post Share on other sites More sharing options...
grahame Posted December 29, 2015 Share Posted December 29, 2015 Sounds like you need to check and reset the back-to-backs. G. Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted December 29, 2015 RMweb Gold Share Posted December 29, 2015 I had a similar problem but with OO gauge code 75. The problem was caused by a Hornby Bulleid that was manufactured at a time when their back-to-back was 14.2mm whereas now it's 14.5mm. None of my later models had this problem. The solution was adjust the back-to-back of the older model, as Graheme has suggested. Link to post Share on other sites More sharing options...
Ch4lkst3r Posted December 30, 2015 Author Share Posted December 30, 2015 Thanks for the response. I haven't got anything apart from a steel rule to measure the back to back perfectly but I'd say that it's about 7.5mm. The model is a new Midland Pullman which I bought last year but have only just got round to running (it's been sat in it's box whilst I sorted out railway room/started laying track etc.) so I would have thought that the back to back wouldn't have needed adjusting. I could understand it with one of my older models although these have still to be chipped. I would say that there is only 0.1mm difference between the Hymek and the Pullman back to back but the Pullman is longer wheelbase. It will traverse all the other points on the layout without any problems and there are small medium and large points, diamond crossings and 3way points too - it's just the double slip and I think it's just the last 1mm approx by the frog V that it's catching with the inside of the wheel. Link to post Share on other sites More sharing options...
RMweb Premium PaulCheffus Posted December 30, 2015 RMweb Premium Share Posted December 30, 2015 Hi I have three double slips and the Farish Pullman which doesn't cause any shorting issues on DCC. I agree with the other comments in that the back to back is probably too big. Cheers Paul Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted December 30, 2015 RMweb Gold Share Posted December 30, 2015 PaulCheffus, on 30 Dec 2015 - 19:32, said:PaulCheffus, on 30 Dec 2015 - 19:32, said: Hi I have three double slips and the Farish Pullman which doesn't cause any shorting issues on DCC. I agree with the other comments in that the back to back is probably too big. Cheers Paul This is an Electrofrog slip and the problem is that the back-to-back is too small. As the axle travels through the frog, the outer wheel is pulled over by the check rail causing the inner wheel to touch the rail in the diamond that is opposite polarity to the one it's actually running on. On an insulfrog point or slip, a back-to-back that is too wide can cause a short on the vee. Link to post Share on other sites More sharing options...
Ch4lkst3r Posted December 31, 2015 Author Share Posted December 31, 2015 Hi, On further investigation (with lots more shorts!) it would appear that the wheelsets are making contact with the switch blade in the middle nearest to the frog (where the 2 are close together) and as RFS said the back to back appears to be too small so it looks like I'll be needing to adjust the back to back. I've just checked an old Minitrix loco (still to be chipped and this is pretty much a match for the Hymek). Any suggestions on where I can acquire a back to back gauge or how to adjust otherwise. I've tried one wheelset and the wheels seem very tight and I don't want to force them too much and end up breaking them. Thanks, Iain Link to post Share on other sites More sharing options...
Ch4lkst3r Posted February 4, 2016 Author Share Posted February 4, 2016 Hi all, Great news. Thanks to your previous advice I acquired a back to back gauge from nbrasslocos and checked the back to backs. After adjusting them (1 wheelset was out by quite a lot) I'm no longer having any shorting problems Thanks again, Iain Link to post Share on other sites More sharing options...
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