doug72 Posted February 21, 2012 Hi - just brought my first Lego train - 7938 - as a trial before deciding to switch from OO gauge model trains to Lego trains. Question: Is there a way that trains & wagons can be un-coupled without touching them. I want to build a gravity coal dock unloading system based on real system that once existed where I live. Doug Share this post Link to post Share on other sites
Mr Benn Posted February 21, 2012 Back in the olde days of 12V (now hitting its 30th birthday!) there was a remote controlled decoupler, 7862 (http://brickset.com/detail/?Set=7862-1) But it didn't work all that well. And there have been none since. I'm sure there are some snazzy moc designs for these around now, some people on this board are amazing at their ingenuity for improving the functionality of the new sets! Share this post Link to post Share on other sites
roamingstop Posted February 21, 2012 Someone on this forum showed a automated system based upon a locomotive with a rack and pinion 'piston' to push magnets apart. Perhaps easier now there are the new mini linear actuators. Other options would be a track based structure which hooks a truck, whilst the locomotive + rake pull apart. Share this post Link to post Share on other sites
bricks n bolts Posted February 21, 2012 I did toy with the idea of replacing the mechanism inside 7862 to use a strong electro-magnet. Haven't go very far.. It would have to be a very flat electro magnet whilst still being very strong (strong enough to decouple the train magnets). The original turning motion in the 7862 would then power the magnet on or off via contacts. As said, the original concept behind 7862 didn't work very well.... Share this post Link to post Share on other sites
doug72 Posted February 21, 2012 The magnets used in the Lego train couplings seem rather odd in that that don't appear to have any polarity i.e. any pair will couple together. Would have thought they were be a set i.e 1 x N & 1 x S Unlike poles attract, like poles repel - Was hoping to use another magnet to repel one half of each coupling. Doug72 Share this post Link to post Share on other sites
Andy Glascott Posted February 21, 2012 This was my only attempt at an uncoupler. The axle moves out of the supervisors deck between two wagons that have stopped, the loco pulls away and the axle holds back the rest of the train. If it gives you ideas, great, feel free to adapt etc, as someone has said, with the linear actuators now available it should be easier to build something like this. Andy Share this post Link to post Share on other sites
roamingstop Posted February 21, 2012 The older 9V magnets are polarised; the upper half N and the lower half S. Thus they spin to align themselves. Share this post Link to post Share on other sites
cimddwc Posted February 21, 2012 Well, the newer magnets do spin, too – just inside their plastic case. Which is of course a good idea because if they'd be fixed as in the early years before the 12V era /when there were red and blue magnets on fixed car bases), you'd often have to grab a car and turn it around by hand. (Strictly speaking, even the old red and blue ones had both poles, the other pole just wasn't accessible; magnetic monopoles are still hypotherical particles...) Share this post Link to post Share on other sites
JamesP Posted February 21, 2012 I did it entirely underneeth a bogie, using a small magnet from Lee Valley, mounted onto a technic axle, with a worm gear on the axle, then a micromotor driving a (8? 12?) T gear, which would push/pull the magnet in behind the buffer beam of a conventional coupling. Several mod's were required in order to operate this: 1. Magnet is glued to 10 or 12L technic axle 2. Mod's to at least 1 wheelset. (carved off a stud, I think...) 3. My layout is DCC, so that's how I operate the micromotor. Sorry, I can't take any photos right now as I am ~6 hrs flying from home :) James Share this post Link to post Share on other sites
Selander Posted February 21, 2012 Someone on this forum showed a automated system based upon a locomotive with a rack and pinion 'piston' to push magnets apart. Perhaps easier now there are the new mini linear actuators. Other options would be a track based structure which hooks a truck, whilst the locomotive + rake pull apart. I posted a design here for a PF built uncoupling system onboard a locomotive. I am on my mobile now, but can update with a link tomorrow. Otherwise I have pictures and a small video on my Flickr - see below ! Share this post Link to post Share on other sites
Dan-147 Posted February 21, 2012 Question: Is there a way that trains & wagons can be un-coupled without touching them. How purely LEGO do you want to go? If you're willing to compromise a bit, you could use Kadee couplers. Remote uncoupling is very easy with these couplers. If you're interested, here's a link to a previous post http://www.eurobricks.com/forum/index.php?showtopic=59221&hl=kadee&st=0 Dan-147 Share this post Link to post Share on other sites
