Curved deck girder bridge options?

[nickelplate759]

My (N-scale) layout needs a curved (approx. 16.5" radius) deck girder bridge.   It needs to be about 40' scale feet long, but can be a little longer.    The prototype (NKP) bridge, near New Haven, IN, was straight.

There are no ready-to-use model bridges that would fit - that's fine.  I'll need to either scratchbuild or kitbash/adapt something.   The layout is using Code 55 rail.

Here are some options:
1.  Scratch build a bridge.  Will need hand-laid track on the bridge.
2.  Use Micro-engineering deck girder bridge.  To look right it will need new bridge ties and hand-laid track as well.
3.  Try and adapt the Kato 20-467 curved deck girder bridge (17 5/8" radius - would be about 60 n-scale feet).   At a minimum the rails would need to be replaced, and the details seem a little clunky.  The prototype didn't/doesn't have hand rails along the walkway, but that's easy to fix.
4.  Punt and substitute a ballasted-deck bridge.

Any thoughts or other ideas?

[C855B]

...
2.  Use Micro-engineering deck girder bridge.  To look right it will need new bridge ties and hand-laid track as well.
...

That's what I did, although I used ME bridge track. My curve was a bit milder, 24".

[John]

there are some curved 3d print files on thingiverse ..

But straight sections would be the way to do it .. use ME bridges

[randgust]

40' really isn't that long.   That would be either an abutment-to-abutment span with no pier, or maybe a single center pier.   And your girder web dimension is a function of that.

I'm assuming NOT ballasted deck from what you describe.   So at that short span length, standard practice is just make it wider, not two separate straight spans, and curve the track in the wider deck.  Ballasted deck would really make it easy though....

When I did one many years ago, I used regular track with ties, and glued 'extensions' on the tie ends to take it across the deck edge to edge.  Then paint all the ties to match.  Today you'd probably RP print the entire deck ties with tie plates and add the rail later.   On my Ttrak triple Hickory Bridge I used ME bridge tie track, 3 spans, through truss.

Two more things to be aware of; railroads now hate walkways (attractive nuisances) and also seem to hate interior guardrails.   What it looked like 'then' and what it looks like 'now' are clues to era.   And no bridge gets painted anymore due to the difficulty of removing lead paint.

[Dave V]

I built this from the Micro Engineering trestle. As has been mentioned, there are no curved girders, only straight segments approximating a curve.

This is ME code 55 bridge track.

I also replaced some of the cross and sway bracing for the towers with piano wire to look like the cable bracing used on the Colorado Midland's iron bridges.

[davefoxx]

With a 16-1/2” radius curve, you can just about build a straight 40’ deck plate girder bridge and lay the curved track right over it without having to do two 20’ sections at an angle to stay under the track.

DFF

[C855B]

Here's a shot from several years ago. You can see most of the ME 80' deck girder on the left. It will be ballasted... someday.

[Mark5]

I would go with Micro-Engineering, though I'm not sure why you feel you'd have to hand lay the track.

Plenty of proto photo references here: https://forum.mrhmag.com/post/curved-bridge-12211581

[nickelplate759]

40' really isn't that long.   That would be either an abutment-to-abutment span with no pier, or maybe a single center pier.   And your girder web dimension is a function of that.

I'm assuming NOT ballasted deck from what you describe.   So at that short span length, standard practice is just make it wider, not two separate straight spans, and curve the track in the wider deck.  Ballasted deck would really make it easy though....

When I did one many years ago, I used regular track with ties, and glued 'extensions' on the tie ends to take it across the deck edge to edge.  Then paint all the ties to match.  Today you'd probably RP print the entire deck ties with tie plates and add the rail later.   On my Ttrak triple Hickory Bridge I used ME bridge tie track, 3 spans, through truss.

Two more things to be aware of; railroads now hate walkways (attractive nuisances) and also seem to hate interior guardrails.   What it looked like 'then' and what it looks like 'now' are clues to era.   And no bridge gets painted anymore due to the difficulty of removing lead paint.

Good points.   From looking at old aerial photos, it appears that the bridge once had two walkways (early 1950s), then one (1960s) and now has none (and no guard rails).   There's not enough detail in the photos to tell if the walkways ever had railings.   Definitely a single span.

I'm going to give the Micro Engineering 40' bridge a shot.

[nickelplate759]

I would go with Micro-Engineering, though I'm not sure why you feel you'd have to hand lay the track.

Plenty of proto photo references here: https://forum.mrhmag.com/post/curved-bridge-12211581

From what I can see, when the track curves on top of a straight bridge, the ties are all parallel to each other while the track curves on top of them.
That said, I may just cheat and go with flexible bridge track.

[NtheBasement]

I have a curved trestle built it before ME came out with bridge flex and made of ME plate girder bridges.  Most of the bridges around here were converted to ballasted long ago but I don't know your era.  The bracing detail on the ME girder bridges is beautiful but unless the bridge is right at the front of the layout you will never see it once you put track down.  So another option is make the ME bridge wider by cutting a wider piece of wood or styrene square tubing and glue the girders to either side.  It is also very easy to scratch build a girder with styrene.  I did that for a much longer trestle using the MEs as a model. Probably the easiest scratchbuild I ever did. [ Guests cannot view attachments ]

[Point353]

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