Stuart Birks Posted March 3, 2015 Share Posted March 3, 2015 For my new layout that I have just stated constructing I came up with this track layout with some help from members of this forum. It wasn't until I built the crossover that I found out how complex the electrical switching is. This means that if the turnout into the siding to the left and the engine shed to the right are both thrown then it all shorts out. I am going to use servos controlled by the servo circuit from MERG and I have made this bracket for mounting the servo and up to 4 microbreak switches. I need three switches for each of the turnouts approching the crossover. The lever gives a reduction in travel so that I can use most of the servo movement to throw the blades giving more control of the setting. I fancy using the lever frame from Model Signal Engineering for operating all my turnouts and signals and the shorting problem started me thinking about making some form of mechanical interlocking between the levers. As usual I got carried away and started thinking about full interlocking of the turnouts, facing point locks and signals. Before I actually go down that route I decided to build a small trial bit of interlocking just to see how it goes. I have built a frame for a turnout with a facing point lock and two signals. The true interlocking rules may not be correct for this. It is just to see if things move correctly and actually lock the levers. Given that the plastic gives a bit it works very well. The real thing will be built in brass if I ever do it. Stu Link to post Share on other sites More sharing options...
RMweb Premium Loxborough Posted March 3, 2015 RMweb Premium Share Posted March 3, 2015 Great solution, and I especially like the bracket you have made up for the servo. So much better than my scrappy woden versions. It seems to me that you have got most of it covered, in particular the interlocking will prevent the shorting issue from conflicting moves. You say at the top of the thread that you need help; not clear to me what you need help with... George Link to post Share on other sites More sharing options...
meil Posted March 3, 2015 Share Posted March 3, 2015 You only need two switches: http://www.scalefour.org/history/images/fig13.html Link to post Share on other sites More sharing options...
Grovenor Posted March 3, 2015 Share Posted March 3, 2015 You only need two switches: http://www.scalefour.org/history/images/fig13.html I agree that only two switches are needed for this section, however be wary of that drawing, it has errors in, with the wiring shown two rail gaps are missing, the gaps are not needed but without them the wiring needs to be changed a bit. Regards Keith Link to post Share on other sites More sharing options...
Stuart Birks Posted March 4, 2015 Author Share Posted March 4, 2015 Thanks for showing that diagram. However I still cannot see how it can be done with two switches. This is the diagram I came up with. With both turnouts straight the crossing frogs are not in use and so do not need to be connected. With the left hand turnout thrown the turnout and both crossing frogs need to be switched. It would be a mirror image for throwing the right hand turnout. However if both turnouts are thrown there is a conflict on the polarity required by the crossing frogs. This is the point at which I realised that interlocking the two turnout levers is required to prevent this. The alternative would seem to be to have a seperate double pole switch that is thrown manually but this would not be an elegant solution. Can anybody show where I have made any errors in my logic. Thanks Stu Link to post Share on other sites More sharing options...
Grovenor Posted March 4, 2015 Share Posted March 4, 2015 However I still cannot see how it can be done with two switches. The linked drawing shows how it is done, on your drawing the frog of the left hand turnout should be linked to the right hand frog of the diamond and switched by the left hand turnout. The frog of the right hand turnout linked to the left hand frog of the diamond and switched by the right hand turnout. All the other switching and connections you have provided are redundant. Note that it is a fundamental feature of live frog diamonds that they can only be used for one route at a time or you will get shorts. Hence the need you correctly identified to interlock the points. The simple way to do this is to use a three position switch, or if using solenoid motors use three push buttons with a diode matrix. Keith Link to post Share on other sites More sharing options...
Stuart Birks Posted March 4, 2015 Author Share Posted March 4, 2015 Thank you. Now I see it. With both turnouts straight bot frogs on the crossing are connected to the black line but that is ok. When one turnout is thrown the correct crossing frog changes with it. Stu Edit - I think I have got my diagram wrong but the idea is ok Link to post Share on other sites More sharing options...
peach james Posted March 4, 2015 Share Posted March 4, 2015 If you intend on going down the path of mechanical interlocking, the Modratrac setup from Australia works well for me...I have a 24 lever frame that is interlocked, I've only had to modify it a little bit to make it more like the real thing (adding a pair of electric locks to it some 7 years after I had built it, to ensure back-locking is possible. http://modratec.com/ James Link to post Share on other sites More sharing options...
Simond Posted March 4, 2015 Share Posted March 4, 2015 You can also speak to Pete at Scale Signal Supply. A very nice, and very prototypical, lever frame is available. 'Tain't cheap, but it is quality. (Usual disclaimers) Best Simon Link to post Share on other sites More sharing options...
RMweb Premium Loxborough Posted March 5, 2015 RMweb Premium Share Posted March 5, 2015 If you intend on going down the path of mechanical interlocking, the Modratrac setup from Australia works well for me...I have a 24 lever frame that is interlocked, I've only had to modify it a little bit to make it more like the real thing (adding a pair of electric locks to it some 7 years after I had built it, to ensure back-locking is possible. http://modratec.com/ James I'm a big fan of the Modratec product, too, but I am keen to see Stuart's scratchbuilt version develop... G Link to post Share on other sites More sharing options...
Gordon A Posted March 5, 2015 Share Posted March 5, 2015 The best mechanical interlocking I have seen on a model railway is on Clutton a P4 layout built and exhibited by Tim Venton, who does occasionally pop up on this forum. As one of the regular operators of Clutton I am impressed on how the mechanical interlocking prevents incorrect signal indications and how it applies discipline to the operation. It is fun to operate. Gordon A Bristol Link to post Share on other sites More sharing options...
Grovenor Posted March 5, 2015 Share Posted March 5, 2015 Edit - I think I have got my diagram wrong but the idea is ok Perfect if you remove the bottom pair of switches, in the first diagram they are just connecting red to red which is not needed. In the second diagram they are potentially connecting red to black, which is not a good idea. Regards Keith Link to post Share on other sites More sharing options...
Stuart Birks Posted September 29, 2015 Author Share Posted September 29, 2015 I have just bought the MSE 7 lever frame. As soon as I started folding the etched partsI was not happy with the way it was going. The main lever is a brass casting and with quite a lot of cleaning up comes out as a nice piece. The main pivot hole is oversized and so I drilled them out and insteted a new sleve so that it pivoted with less play. The latch release lever is a horrible item with an action which moved the latch lifting rod more away from the lever than lifting it. I thought I could do better so made a new lever out of a bit of brass and steel. This was successful and so I decided to make a new version of the latch as well. This is an overall view of the frame. I have only finished one lever at this stage. This is a closer view of the new latch lever and latch plate that I have made. The next dissapointment is the very large gap each side of the lever. Even with the sleeved bearing there is still a lot of movement in this slot. So the final outcome is that I will build my own frame as well. Thankfully MSE sell the cast levers seperatley and so I am planning to buy the levers I need and make everything else. Stu Link to post Share on other sites More sharing options...
Stuart Birks Posted May 14, 2016 Author Share Posted May 14, 2016 After much more work than I first anticipated the lever frame is virtually finished. I just need to put in some form of end stop for the lever travel, buy some more switches and get the brass lever number plates etched. The simulated floor is just a trial but something similar will form the surface of my control panel. The interlocking frame will be hidden under the layout. Stuart Link to post Share on other sites More sharing options...
Simond Posted May 14, 2016 Share Posted May 14, 2016 That's excellent! Link to post Share on other sites More sharing options...
micknich2003 Posted May 14, 2016 Share Posted May 14, 2016 Here's a couple of pictures of a locking frame I made many years ago. I followed full size practise and put Five Bars in each box, two bottom and three top. The bars are 1/8in sqaure bar, the locks are from 1/16 x 1/4 strip, rivetted to the bar with 1/32 wire. In addition to the ordinary "Locking and Releasing" there are also two pieces of "Conditional Locking". Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted May 14, 2016 RMweb Premium Share Posted May 14, 2016 After much more work than I first anticipated the lever frame is virtually finished. I just need to put in some form of end stop for the lever travel, buy some more switches and get the brass lever number plates etched. The simulated floor is just a trial but something similar will form the surface of my control panel. The interlocking frame will be hidden under the layout. Stuart It's such a work of art, why would you want to hide it below the layout? It deserves to be seen, that's the conundrum. Link to post Share on other sites More sharing options...
dajt Posted May 16, 2016 Share Posted May 16, 2016 Great job, well done! Link to post Share on other sites More sharing options...
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