Large Scale Central

Bridge building

Track and Trestles
#1

Our little layout needs a bridge. We have it spanning a pond in a very prominent place, and the temporary thing I threw up is no good.

So I sent an email to Eagle wings ironworks asking for a price quote on a specific design and got no response. They’re pretty pricey If I wanted to build one myself, what kind of options am I looking at? I don’t want wood–it’s not the look we’re aiming for. I haven’t done any welding since middle school shop class and don’t have any equipment. The span to be crossed is 56 inches, and the track crosses at just under 12 inches high. Anybody have any homemade bride solutions to post?

#2

Try Bruce’s article on building a turntable. TTs and bridges are basically the same thing. If the spans can fit in a 12-16" space the abutments and supports holding it can be made from wood, plastic, concrete. Personally I like trestles and wooden truss bridges, but I also have a fondness for wood.

(http://www.geocities.com/RodeoDrive/4497/Brdg3.jpg)

#3

Ah, nice metal bridge. You can get a 46" long Garden Metal Models bridge…not quite long enough, but you could get some of their pylons and add a 12" or 24" to it for a nice look. They do hold up well and look nice.

(http://www.jbrr.com/assets/images/P1040055.jpg)

They also sell a railing kit that would look good in 1/29. If you want to make one, you could use the TufBoard. Make it like I did my turntable, with styrene “T” pieces and it would look nifty. But I’d be concerned with the potential for the TufBoard to sag over 56". One option might be to build it around a piece of steel, perhaps just some rebar. You’d lose some of the inner details, but you seldom see it anyway. I think Bob made one using a drainspout as the main structural piece. Again, you could put some styrene on this and paint it, and never know the difference from a distance.

#4

I thought about the Garden Metal Models bridge, but the pylons would need to be 56 inches apart

Right now it’s just a piece of sole plate, the kind you use for framing walls with steel studs, with 1x stock for added stiffness. I suppose I could dress it up with styrene to look like an astonishingly long thru-girder bridge. Hmm

#5

Does it have to span 56"? Or can you have some pylons in the middle, or towards one end? For instance, you could get 2 of their 36" bridges. or a 46" and and 12". Could be a neat look…

I only ask because it looks like you have some bricks supporting it now…

The sole plate sounds like a good base. And 56" does make for a long bridge, but so what? :wink:

#6

You could build the span substructure with channel or angle iron to eliminate sags, and then fasten the sectional Garden Metals Bridge to it. If you used 1/4’ channel, you could walk across it yourself!
Make abutments at each end by pouring a footing and stacking concrete blocks to the desired height.
jb

#7

That’s an interesting idea John. I’m not exactly sure how those garden metal models bridges work. They can be fastened together?

I’m also thinking this is the central showpiece of the layout, I ought to do something really good. I’ve been thinking for a while about building a suspension bridge. Anybody ever do that?

#8

Mike,

There have been some suspension bridges posted here or at “the other place,” where ever that is, :smiley: so you could go looking. If you have some experience from high school, it shouldn’t be too hard to buff up your skills. Your school probably has a shop where you could schmooze some welding time, with tutoring if you want. Or, the local JC or community recreation department probably offers some welding classes, either as part of their auto repair or art departments.

Basic welding equipment doesn’t cost that much, and pretty soon you’ll be making bridges for all of your buddies.

Go for it!

#9

Yup. ABS square downspout and styrene T and angle

(http://zbd.com/photos/OnePoint20/DeckGirderBridge/DSCF1140.JPG)

being built:

(http://zbd.com/photos/OnePoint20/DeckGirderBridge/DSCF1125.JPG)

If you need invisible support, put some 1" aluminum channel inside and screw it to the top

#10

Oh snap!, as my son’s friends say! That looks great Bob. Do you have any more pictures of how you did that?

#11

Er, not really. Here’s one with grey primer on it.

(http://zbd.com/photos/OnePoint20/DeckGirderBridge/Primer2.jpg)

its pretty straight forward. 1/4" angle top and bottom, and 3/16 tee for the verticals. I suppose you could do 3/16 angle for the uprights, too.

#12

And you got the downspout where?

The Styrene glues to it well?

#13

Bob, you never cease to amaze me.

#14

Local hardware store has it. Its pretty cheap, too, if I remember, $5 or $8 a 10 foot length.

#15

I just ducked out to home depot, about a mile away–they don’t carry it. I’ll check some other sources

#16

Yea, HD doesnt here either, but the local Aubuchon hardware does. Its manufactured by Genova.

On gluing, I was using MEK, but use it OUTSIDE. Its incredibly bad to breathe in. Other styrene adhesives should work, too.

#17

On a similar note, anyone know a source for the kind of PVC tubing used in the “Ninth Bridge” article in August 2008 GR? I’ve looked around a bit but havent found a source.

#18
Bob McCown said:
Yea, HD doesnt here either, but the local Aubuchon hardware does. Its manufactured by Genova.

On gluing, I was using MEK, but use it OUTSIDE. Its incredibly bad to breathe in. Other styrene adhesives should work, too.


MEK is a solvent. Works great on plastic but use sparingly. It “fuses” plastic. Too much will literally dissolve a part.
MEK was the active ingredient in the liquid “Testors” plastic cement years ago. Kids were sniffing it so they removed most, if not all the MEK.
Ralph

#19

Hmm, I like that ABS downspout idea!

#20

I can’t find any square ABS downspout around here–not yet anyway. I’ll keep looking