MOC: Remote controlled decoupling mechanism

[Selander]

Old 9V + New PF => To combine the best from two worlds ?

Background and goals:

In the old 12V-system there was a stationary remote controlled, decoupling system. How about recreating something similar with elements available these days?

Comparing the pros and cons of a stationary versus a “rolling” decoupling solution, I’d prefer the later because of the obvious advantage of decoupling at any place along the layout.

Until recently I have been somewhat reluctant to the new PF train system, and I still think the old 9V system has its advantages, but at the same time, I must admit that using PF elements also opens up many new opportunities.

My Swedish Railways RC-locomotives are reasonable copies of the prototype, but they are “simply” equipped with a 9V train motor (ref 5300) and have no other technical functionality. So how about integrating PF elements in the locomotive body, but keeping the 9V motor intact for reliable propulsion?

My goal was to add:

- working lights in front, plus:

-integrate a decoupling system in the locomotive, with a minimum change of the external design.

-both features should be realized by remote-controlled battery operated PF-items.

-also I wanted to keep the Lego original magnet coupling system to allow using any standard rolling stock with my locomotives.

Design phase:

Main challenge was to fit all PF-stuff, such as a battery box, IR receiver, PF-motor + racks, lights etc in the relatively small size locomotive 6 x 28 studs (external dimensions). Considering a drivers cab in each end, and sides built from bricks, there was a limited room for all items needed. So which solution could work AND fit?

Because of the strong magnetic force in couplings, I needed to create a distance of approx 40mm, (1½”) between locomotive and first wagon, to make the two magnet fields “loose contact” with each other. So my primitive idea was to physically push the wagons away from the locomotive using a 40mm stroke “piston”. To do that I was thinking in three alternative ways:

A) Using a linear actuator. B) Using a wheel with a technic beam as “piston”. C) Using a gear rack as a “piston”. After some thinking, trials and consideration of space needed, I decided to go for alternative C, using a 1 x 10 studs long gear rack + a simple gear design.

Realization:

Locomotive body has been stretched 2 studs, so it now measures 6 x 30 studs externally, (6x28 base + "1 stud" SNOT front & rear) to give a little more internal space. Front has been re-built to fit PF-lights, and the rear has a small hole which allows the 1 x 10 studs gear rack to go in/out. To drive the "piston" I use a PF-motor Medium. I know it is basic and primitive, but it works. Roof is slightly rebuilt so the top of IR-receiver is visible for reliable operation. For remote control I’ve tried both 8879 and 8885, but the later is much better for my application, since gear rack must be run in/out at a minimum speed, and also LED-lights can be switched on permanently at the lowest power ( to save batteries).

So…..here are finally some shots and a small video showing the results:

-Internal view showing a full locomotive body with PF stuff.

-Train front with PF lights which can be lit also when locomotive is “still” (compared to old 9V-lights).

-Gear rack pushes wagons to physically separate them from loco magnet.

IR reciever can be seen on roof.

Short video link:

video on my Flickr

Conclusion

It was possible to combine the best of two worlds for added fun and functionality!!!

IF putting more efforts into decoupling issues, I am sure the talented builders of this forum can come up with a better-looking and more smoothly working solution than mine. So I hope you can accept this is a challenge to develop an even better decoupling system.

Anyhow, I hope you enjoyed reading/watching, and please feel free to comment.

[andythenorth]

Nice.

[JopieK]

but it would be way more elegant to have a decoupler alongside of the tracks and a shunting hill. If we were able to come up with a really small version one could embedded it at multiple places along side the track.

[peterab]

I have been toying with this idea for some time, my plan was to retract the engines magnet (using the buffers to hold the carriage at bay, but I didn't get further than daydreaming. It's great to see someone actually try it out. It's also a credit to you that you managed to incorporate it into one of you great Mocs without changing the looks too much.

but it would be way more elegant to have a decoupler alongside of the tracks and a shunting hill. If we were able to come up with a really small version one could embedded it at multiple places along side the track.

I think the onboard system is way more flexable though.

[vgo]

If you had the decoupler mechanism in every wagon, then I'd call it "flexible".

I've made a simple decoupler mechanism that is embedded in the track, two "fingers" raise from the track and push the magnets apart.

[lostdriveway]

If you had the decoupler mechanism in every wagon, then I'd call it "flexible".

I've made a simple decoupler mechanism that is embedded in the track, two "fingers" raise from the track and push the magnets apart.

That I would like to see!

[Rob Klingberg]

Nicely done, and very creative! I agree that a mobile decoupling mechanism is more flexible than a stationary one (though since I'm a big 12v user I have the luxury of at least having those!).

I was thinking about how to accomplish remote decoupling as you have done, and I always wondered whether it was possible to somehow energize one of the coupling magnets to cause a temporary reverse in polarity, which would repel the other magnet, thus decoupling the loco. I'm not an expert on magnetism so I don't know if any of this is even possible, but I always thought that would be another extremely elegant way to accomplish the same effect.

--Rob

[locoworks]

Nicely done, and very creative! I agree that a mobile decoupling mechanism is more flexible than a stationary one (though since I'm a big 12v user I have the luxury of at least having those!).

I was thinking about how to accomplish remote decoupling as you have done, and I always wondered whether it was possible to somehow energize one of the coupling magnets to cause a temporary reverse in polarity, which would repel the other magnet, thus decoupling the loco. I'm not an expert on magnetism so I don't know if any of this is even possible, but I always thought that would be another extremely elegant way to accomplish the same effect.

--Rob

it won't work because the magnets can rotate and it would just make the touching magnet spin round and recouple. another option, though not remote in the sense of can be uncoupled anywhere, but just specific places hands off, would be to use a completely different coupling system. 'O' gauge 'kadee' couplers from the 'proper' ( sorry folks ) railway modelling world could be fitted and used as on 'normal' ( sorry again ) model railways. some enterprising bod may come up with a specific lego compatible moulding to fit them easilly at a suitable height and distance from from the stock ends?? maybe even the 'G' scale coupling one for a real chunky look??

Edited December 21, 2010 by locoworks

[erik530195]

I saw some of your MOC's in your signature. Nice work. Oh and a cool train too....

[peterab]

If you had the decoupler mechanism in every wagon, then I'd call it "flexible".

I've made a simple decoupler mechanism that is embedded in the track, two "fingers" raise from the track and push the magnets apart.

Oh I see what you mean, I was thinking of the engine only and assuming the cars would stay in the same consist, which for passenger trains can happen, but for freight you want to shunt individual cars. Perhaps we need a bit of both :-)

it won't work because the magnets can rotate and it would just make the touching magnet spin round and recouple. another option, though not remote in the sense of can be uncoupled anywhere, but just specific places hands off, would be to use a completely different coupling system. 'O' gauge 'kadee' couplers from the 'proper' ( sorry folks ) railway modelling world could be fitted and used as on 'normal' ( sorry again ) model railways. some enterprising bod may come up with a specific lego compatible moulding to fit them easilly at a suitable height and distance from from the stock ends?? maybe even the 'G' scale coupling one for a real chunky look??

There is some picture of this on Flickr

http://www.flickr.com/photos/18414760@N02/4714957167/

[JopieK]

That I would like to see!

Me too! I have and idea though that is inspired by this topic. We could make a trick pit. The decoupler could move back and forth in that pit and then decouple the train remotely. An hall sensor could feel the magnet for right positioning.

[Selander]

Nicely done, and very creative! I agree that a mobile decoupling mechanism is more flexible than a stationary one (though since I'm a big 12v user I have the luxury of at least having those!).

I was thinking about how to accomplish remote decoupling as you have done, and I always wondered whether it was possible to somehow energize one of the coupling magnets to cause a temporary reverse in polarity, which would repel the other magnet, thus decoupling the loco. I'm not an expert on magnetism so I don't know if any of this is even possible, but I always thought that would be another extremely elegant way to accomplish the same effect.

--Rob

Thanks Rob !

I have been thinking about magnet "manipulation" too.....but haven't tried in IRL....(yet)

One theoretical way that I have been thinking of, could be to replace the normal Lego magnet with an electro-magnet on locomotive.

An electro-magnet is only magnetic when a current flows through it (a coil over a iron core), so the magnetic force is possible to turn

on/off remotely.

But as it consumes continuous power during hauling, I assume that would drain the batteries very quickly, if even technically possible.

Generally, I prefer to stick with a solution which is 100% non-modified Lego, as in the design I posted

[locoworks]

Thanks Rob !

I have been thinking about magnet "manipulation" too.....but haven't tried in IRL....(yet)

One theoretical way that I have been thinking of, could be to replace the normal Lego magnet with an electro-magnet on locomotive.

An electro-magnet is only magnetic when a current flows through it (a coil over a iron core), so the magnetic force is possible to turn

on/off remotely.

But as it consumes continuous power during hauling, I assume that would drain the batteries very quickly, if even technically possible.

Generally, I prefer to stick with a solution which is 100% non-modified Lego, as in the design I posted

with an iron core and a DC supply i think the electromagnet will soon become a permanent magnet courtesy of the magnetised core??

[JopieK]

with an iron core and a DC supply i think the electromagnet will soon become a permanent magnet courtesy of the magnetised core??

And there will be more problems like overheating etc.