I’m getting to the point in building my double decker HO PRR / NYC layout where Iam on th etop level and I need two bridges to cross a 24" gap. I have two single track lines. One is the main line and in front of that is a seperate lead track from the yard that will be used by switchers when creating trains. The tracks are 5" apart. So 2 bridges are reauired. After all of that… any ideas as to what bridges to use? I’m thinking of a girder bridge or a more detailed bridge for the mainline and a simple bridge for the lead track.
There seems not to be many pre-made bridges out there to use (if you know of any, please let me know!)
Subsequently I’m seriously considering scatchbuilding the bridges (built a wooden bridge on a previous layout that looked very good). I have the MRR ‘Bridges and Trestles’ book. Has anyone access to any plans or has built a detailed bridge about 24" in length? (Can we see them?)
Any good tips for scratchbuilding and lessons learned?
Thanks guys! [8D][8D][;)]
The Heljan trestle kit is very flexible and can be easily modified or even divided to make several bridges (Lots of parts.[:P])
I don’t remember if it will span 24" but it seems that it would be close.
Just a thought.
What scale and era are you working in? What part of the country are you trying to portray?
besteel, this ballasted deck girder bridge spans 26". It’s made from 2 50’ and 3 30’ Micro Engineering ballasted deck girder kits. DJ.
Try a pair of the Walthers Cornerstone Single Track Truss Bridge:
http://www.walthers.com/exec/productinfo/933-3185
Rich
Tony Koester wrote a 6-page article, “How to Build A Viaduct,” in November 2010 Model Railroader, for his Nickle Plate Road layout. In fact, the NKP steel viaduct resembles Grampy’s above photo – Except it is all-steel, and at a higher elevation as it climbs up Cayuga Hill from the Wabash River Valley.
The scratchbuilt steel deck bridge is formed around aluminum channel while incorporating parts from manufacturers like Micro Engineering and Central Valley.
The in-depth article includes visits & photos at a prototype (abandoned) NKP bridge, painting & weathering, backdrop & mockups, proper (backdrop) forced-perspective, modeling the stream, bridge abutments, etc.
As an afterthought, even though the two bridges will be separated by 5" – It might be nice to have the bridge closest to the backdrop, slightly higher in elevation for scenic purposes.
Hi
HO as I said in my post. It’s Ohio, PRR and NYC c 1953.
I would go with a single track truss on the main and a couple of plate girders on the secondary. If the truss isn’t quite long enough, I have seen many models and prototypes where a truss bridge has a plate or deck at one or both ends of it.
Just my thoughts.
Good luck,
Richard
Let me also strongly recommend the Paul Mallery Bridge & Trestle Handbook. It is not really a how to book by any means but is chock full of more ideas – particularly about what kind of bridge a railroad would use in a particular situation, and particular era. I suspect the other Kalmbach book on bridges, the more recent Jeff Wilson one, is also very good.
Since it is unlikely that a commercial bridge is out there that is exactly the length you need, my own approach would be to consider first what you are looking at in the way of bridge abutments, the likely need for there to be two, or three, central bridge supports, and then explore using the Atlas flat car girder load, which is pretty much like their girder bridge but just the sides, and perfectly suited to careful cutting and bashing – making longer or shorter – to the length you need.
Dave Nelson