Subject:
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Re: A power rail idea
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Newsgroups:
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lugnet.trains
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Date:
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Wed, 17 Oct 2007 09:08:51 GMT
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Viewed:
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7136 times
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In lugnet.trains, Dave Curtis wrote:
> OK, so 9V is dead. Not a happy thought.
>
> Still, the engineer in me can't help but think about ways to work within the new
> regime. After 40 years of off-and-on model rail and toy train activity, the
> first thought that comes to mind is that anyone who thinks batteries will be
> sufficient in a display situation is delusional. On the other hand, a train
> system based on the new power function motors looks like it has some real
> opportunities for interesting loco models. Think big wheels, techic parts...
>
> So the real question is how to deliver power to the motors in a way that is
> upward compatible with plastic R/C track. A thought that comes to mind is a
> "power tile". A power tile would be one stud wide, and have two conductors, one
> running along each edge. It would be placed directly on either row of studs
> that is next to the (between studs) track center line. There would need to be a
> power pick up brick with three brushes, one brush picking up the power rail
> closest to track center, and two other brushes placed so that they pick up the
> "outside" power rail, one brush on each side of center so that it doesn't matter
> which side of center the power tile is on. (Only one of these outside brushes
> would be active at a time.)
>
> A simple track cross section, where | is rail, ^ is power tile:
>
> _|__^_|_
>
> (Forgive the ASCII art, I'm too lazy tonight to make fancy drawings.)
>
> Note that all reverse loop problems magically disappear, since the conductor
> closest to center is always the same polarity. It would also be easy to splice
> a DCC decoder in between the brush brick and the motor. This is upward
> compatible with plastic R/C track, since the power tile is simply an optional
> extra part.
>
> Issues:
> 1. Would need two sets of pick up brushes per loco to cross gaps reliably. Pick
> up brushes might be built into axle holder bricks.
> 2. Crossings and turnouts will need special power tiles with gaps. Or better
> yet, a new powered turnout that matches power tile standards.
>
> This is easy to prototype in a crude fashion. Of the many codes of H0 and N
> scale rail, there must be one that is about one tile tall. With epoxy, one
> could glue one rail down the center line, and glue on another rail one stud
> over. With a few snippets of phosphor bronze sheet metal you have pick-up
> brushes. Or, it could be prototyped by modding 1x8 tiles by adding strips of
> copper tape on each side, although copper tape may not last long. Maybe some
> brass L stock glued to a tile would work better.
>
> The profile of a 1 stud wide tile might not be the best profile for a power
> tile, something more trapezoidal might allow better brush tracking. In any case
> the tile can't get too tall without causing clearance problems with existing
> equipment.
>
> Anyway, just some random thoughts tossed into the public domain for discussion.
>
> -dave
Not a bad idea. However, I used to have a decent layout in the 70's (my Dark
Ages) using the 12V system, which is not too far from what you are proposing. It
would require Lego to come up with new parts, including a complicated switch.
Also, I remember the brushes and metal center track would erode over time after
extensive use, removing the protective tin top coat causing sometimes even some
localized corrosion. Though it worked fine as a toy for a kid, the reliability
was not up to snuff for serious display work...
As for batteries: I fully agree that a 6*"AA" based train would probably be the
least usefull Lego could come up with to replace the 9V system. One suggestion I
was thinking of is using high-quality Lithium Ion rechargeable batteries. A
Power functions XL motor should be able to run for at least 5 hours continously
(loaded) on a 3000 mAh battery (easily doable in the formfactor of current Lego
battery boxes). To charge these batteries, Lego could come up with a "charging
rail" (similar to what they did
in the 8364 Racers Multitrack Challenge). Every train has to stop sooner or
later; might as well use this stop to recharge. I know this is by far not as
good as ye olde 9V system, but it certainly beats swapping AA's every 3 hours.
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Message is in Reply To:
 | | A power rail idea
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| OK, so 9V is dead. Not a happy thought. Still, the engineer in me can't help but think about ways to work within the new regime. After 40 years of off-and-on model rail and toy train activity, the first thought that comes to mind is that anyone who (...) (17 years ago, 14-Oct-07, to lugnet.trains)
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