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I want to build a bridge to cross a one-meter gap between two train
platforms. The bridge must hold two straight lengths of track, spaced
with one trackwidth between them (the distance there would be if you
snapped two cross-intersection track pieces together).
The platforms themselves are a meter off the ground, so putting a
support in the middle of the span isn't feasible.
Two years ago I grabbed one of every Znap set from a TRU clearance.
I've been using that to try to build a beam bridge. I've gotten the
beam reasonably rigid, but my problem right now is that it twists very
easily, and I can't figure out how to support against that.
Any tips on how to build a sturdy one-meter-long bridge out of Znap
and/or Technic while being somewhat miserly with the pieces, so I don't
run out? And any tips on how to reinforce against twisting would be
greatly appreciated, thanks!
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In lugnet.trains, Brian Kendig writes:
> I want to build a bridge to cross a one-meter gap between two train
> platforms. The bridge must hold two straight lengths of track, spaced
> with one trackwidth between them (the distance there would be if you
> snapped two cross-intersection track pieces together).
...
Brian:
I've built some ZNAP and Technic bridges of similar lengths but haven't run
into the twisting problem. Any chance you can post a picture of what you
have? That would help a lot.
Cary
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Here is one photo of my lift bridge that has a 32" span (approximately):
http://www.brickshelf.com/gallery/msltc/20020921/Bridges/bridges-013.jpg
It holds up very well, and i assume that you could make it even longer if
you needed to.
-Rob
www.cei.net/~rhendrix/lego.html
www.msltc.org
"Brian Kendig" <brian@enchanter.net> wrote in message
news:brian-D11855.15212123012003@news.lugnet.com...
> I want to build a bridge to cross a one-meter gap between two train
> platforms. The bridge must hold two straight lengths of track, spaced
> with one trackwidth between them (the distance there would be if you
> snapped two cross-intersection track pieces together).
>
> The platforms themselves are a meter off the ground, so putting a
> support in the middle of the span isn't feasible.
>
> Two years ago I grabbed one of every Znap set from a TRU clearance.
> I've been using that to try to build a beam bridge. I've gotten the
> beam reasonably rigid, but my problem right now is that it twists very
> easily, and I can't figure out how to support against that.
>
> Any tips on how to build a sturdy one-meter-long bridge out of Znap
> and/or Technic while being somewhat miserly with the pieces, so I don't
> run out? And any tips on how to reinforce against twisting would be
> greatly appreciated, thanks!
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In lugnet.trains, Brian Kendig writes:
> I want to build a bridge to cross a one-meter gap between two train
> platforms. The bridge must hold two straight lengths of track, spaced
> with one trackwidth between them (the distance there would be if you
> snapped two cross-intersection track pieces together).
>
> The platforms themselves are a meter off the ground, so putting a
> support in the middle of the span isn't feasible.
>
> Two years ago I grabbed one of every Znap set from a TRU clearance.
> I've been using that to try to build a beam bridge. I've gotten the
> beam reasonably rigid, but my problem right now is that it twists very
> easily, and I can't figure out how to support against that.
>
> Any tips on how to build a sturdy one-meter-long bridge out of Znap
> and/or Technic while being somewhat miserly with the pieces, so I don't
> run out? And any tips on how to reinforce against twisting would be
> greatly appreciated, thanks!
Well there's Wayne Hussey's bridge which was built out of znap
http://news.lugnet.com/trains/?n=6992 it's a bit longer than you need, but I
imagine it would've been impossible to use if it had a twisting problem.
Maybe you could adapt his deck construction technique?
Also I built this small bridge
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=13433 which is very stable,
and could be extended and widened quite easily.
ROSCO
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In lugnet.trains, Brian Kendig writes:
> I want to build a bridge to cross a one-meter gap between two train
> platforms. The bridge must hold two straight lengths of track, spaced
> with one trackwidth between them (the distance there would be if you
> snapped two cross-intersection track pieces together).
>
> The platforms themselves are a meter off the ground, so putting a
> support in the middle of the span isn't feasible.
>
> Two years ago I grabbed one of every Znap set from a TRU clearance.
> I've been using that to try to build a beam bridge. I've gotten the
> beam reasonably rigid, but my problem right now is that it twists very
> easily, and I can't figure out how to support against that.
>
> Any tips on how to build a sturdy one-meter-long bridge out of Znap
> and/or Technic while being somewhat miserly with the pieces, so I don't
> run out? And any tips on how to reinforce against twisting would be
> greatly appreciated, thanks!
Well, Brian, I can say one of my 60 inch long ZNAP bridge twisted and
collapse at a train show, with the GFLTC (no pics). Two trains fell 30+
inches to the ground out side in the dirt! The best bet for a ZNAP bridge is
to support the track on both side with walls or three support walls with two
tracks. The bridge that collapse only had side walls, no wall in the center.
Here are some examples:
Two ZNAP bridges at GATS Orlando (30in long):
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=62456
Twin track ZNAP bridge at GATS Tampa (30in long):
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=127169
Twin track ZNAP bridge at FLBG Largo (41in long) upper left:
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=282855
Working draw bridge NMRA NTS Ft. Lauderdale (30in long):
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=216610
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=216611
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=216612
Hope this helps,
Robin W
GFLTC - www.gfltc.org
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"Cary Clark" <cary@corp.nospamwebtv.net> wrote in message
news:H96p3M.I6q@lugnet.com...
> In lugnet.trains, Brian Kendig writes:
> > I want to build a bridge to cross a one-meter gap between two train
> > platforms. The bridge must hold two straight lengths of track, spaced
> > with one trackwidth between them (the distance there would be if you
> > snapped two cross-intersection track pieces together).
> ...
>
> Brian:
>
> I've built some ZNAP and Technic bridges of similar lengths but haven't • run
> into the twisting problem. Any chance you can post a picture of what you
> have? That would help a lot.
>
> Cary
Here are a couple of pictures of the ZNAP bridges Cary built along with one
I built.
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=50749
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=149776
Cary built the two bridges that cary the trains across the opening in the
NCLTC layout, I built the monorail bridge. When we set up for our first
GATS show one of Cary's bridges worked great and one didn't, it sagged a
bit. My monorail bridge was also structurally not sound. After we went
home that Friday night Cary made a second copy of the bridge design that
worked and I re-worked my bridge design completely. We have used all three
bridges at numerous shows since then without any problems.
While I have a tub of ZNAP, I didn't have enough of the parts that I would
have really liked to use so I had to be creative. For the bottom platform I
alternated triangle pieces such that two of them placed next to each other
formed a crude rectangle. I then joined these rectangles together with the
sides. At this point the bottom rectangles were not joined together with
each other so I used a seried of long ZNAP beams connected end to end on the
underside to create one long rib down the middle of the base. This turned
out well and it is very sturdy, the rib provides more than enough support.
You can't really see it in the picture but the rib follows the centerline of
the monorail track.
Mike
--
Mike Walsh - mike_walsh at mindspring.com
http://www.ncltc.cc - North Carolina LEGO Train Club
http://www.carolinatrainbuilders.com - Carolina Train Builders
http://www.bricklink.com/store.asp?p=mpw - CTB/Brick Depot
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Brian,
Here's my znap bridge I did. It's pretty sturdy, albeit somewhat heavy as
well due to the amount of plates I used on the base.. It's a double 6-wide
train bridge. The trick that I did was using the 2x2 brick and half stud
pieces combined with plates (if you didn't know, those holes in znap are the
same size as technic pins). If you insert one of those bricks into the znap
holes on one side of the znap, then insert another one on the second or
third set of holes, you can bind the two bricks with a 6-wide plate, which
will almost eliminate twisting of the znap. This trick works even better
when you can sandwich it at a joint. The nice thing is that when you do it
this way, the plate will lay right on top of the znap as well. My bridge is
about 100-110 studs long (about 3.5 baseplates, which puts it at about 32-35
inches long. I think that's pretty close to the roughly 40 inches that
equals a meter. The 2x2 bricks are hidden from view because they are on the
underside of the base.
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=105239
here's the start of a road bridge I've now completed (completed pics not up
yet). The key thing in making it straight was balancing the weight against
the two baseplates that the ramp is connected to. The bridge now
accomodates three elevated sections, and doesn't sag unless you put a large
load of weight on it (Like one of Stacy Bledsoe's Big Boy trains)...even
then, after 8 hours overnight, it sagged about an inch (or so he told me)
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=202614
However, making two towers at each platform and running cables from the
towers down to the bridge (like Wayne's) does look like a cool idea.
Scott Lyttle
> Any tips on how to build a sturdy one-meter-long bridge out of Znap
> and/or Technic while being somewhat miserly with the pieces, so I don't
> run out? And any tips on how to reinforce against twisting would be
> greatly appreciated, thanks!
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In lugnet.trains, Brian Kendig writes:
> I want to build a bridge to cross a one-meter gap between two train
> platforms. The bridge must hold two straight lengths of track, spaced
> with one trackwidth between them (the distance there would be if you
> snapped two cross-intersection track pieces together).
>
> The platforms themselves are a meter off the ground, so putting a
> support in the middle of the span isn't feasible.
>
> Two years ago I grabbed one of every Znap set from a TRU clearance.
> I've been using that to try to build a beam bridge. I've gotten the
> beam reasonably rigid, but my problem right now is that it twists very
> easily, and I can't figure out how to support against that.
>
> Any tips on how to build a sturdy one-meter-long bridge out of Znap
> and/or Technic while being somewhat miserly with the pieces, so I don't
> run out? And any tips on how to reinforce against twisting would be
> greatly appreciated, thanks!
Hello Brian,
The NBLTC has displayed with two such bridges, both made of technic though.
The first one is of an arched design and spans 6 straight track lengths. I
can vouch for it's strength as my 2 year old daughter tried to walk accross
it and it held.
http://www.nbltc.org/images/gallery/events/s020629/rerunbr.jpg
The other bridge shown here is a girder type by David Stenhouse spanning 8
straight lengths. Hope these will inspure you!
http://www.nbltc.org/images/gallery/events/s020921/canyon.jpg
Regards,
Jon Reynolds
www.nbltc.org
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