Subject:
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Micromotor Point Switcher (!)
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Newsgroups:
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lugnet.trains
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Date:
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Fri, 7 Jun 2002 20:17:31 GMT
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Reply-To:
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jrclark@nospam.aol.com^StopSpammers^
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I've been looking for a new way to do remote point switching. I wanted a
system that met the following criteria:
1. Uses an unmodified point.
2. Smaller and more unobtrusive than existing designs.
3. Simple and reliable.
4. Won't tear itself apart if left on for short periods
(especially important for computer-controlled applications).
5. Indicates switch position from a distance.
6. 100% LEGO with no rare pieces.
7. Can be removed and re-installed fairly easily.
I believe I've got it. My new design meets all these requirements in a
5x5x5 space. Taking a cue from traditional model railroading, I
completely circumvented the point's main mechanism, and directly
activated the spring-loaded piece on the track itself. While this method
has two drawbacks (discussed below), I believe they are minor enough for
most applications.
The switcher works by using a micromotor [1] to push an activator rod
(actually a LEGO spear) through the small hole at the end of the switch.
The switch starts in the "mainline" or straight position. When the motor
is turned on, it physically pushes the track into the switched position.
Reversing the procedure allows the spring-loaded piece to reset itself.
Please see the following Brickshelf folder for construction details:
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=18637
This method has two minor drawbacks.
First, when the point is in the switched, or "non-mainline" position,
trains must not enter the point from the other side of the mainline.
This is prototypical for real railroads, as well as model railroads, but
LEGO train people are used to allowing trains to pass a switch that is
turned the wrong way. If you do that using this switcher, your trains
will derail. The switch must be set correctly for all mainline traffic.
Second, and more importantly, since the point's main switching mechanism
is bypassed, the electrical switching is bypassed as well. As a result,
the siding will be electrically dead, even when the point is set to it.
This can be remedied by making the point fully powered. This means you
can't park unused engines on the sidings (without much more complicated
wiring), but other than that, it does not affect the trains.
To power the siding, simply use an electrical jumper to connect the
unpowered track of the siding to the corresponding powered track of the
mainline. This can be done (expensively) with two LEGO track power
connectors, but I decided to go non-LEGO for this part of the project.
Doing so meant a cost of less than a dollar, versus $12 for the two LEGO
connectors. See the following photo for clarification on where to
connect the wires:
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=185589
And see my earlier thread for more options and construction details for
cheap power jumpers:
http://news.lugnet.com/trains/?n=16617
Well, there you have it. I have no doubt that my design can be improved
upon. Please feel free. But also try it, and see what you think. Thanks!
Rick Clark
PNLTC
[1] Micromotors are currently available for $9.95 from Pitsco/Dacta at
800-362-4308, or online at:
http://www.pldstore.com/pitsco2_30/finditem.cfm?itemid=11
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Message has 3 Replies:
 | | Re: Micromotor Point Switcher (!)
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| I've played with Rick's solution first hand and I think it is one of the most elegant solutions out there. Ricks' writeup doesn't give himself enough credit for his ingenious design. I especially like how the spear piece is fitted in the slot in the (...) (22 years ago, 8-Jun-02, to lugnet.trains)
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