My bents use square redwood cut from fence boards. I model in 1:20.3 so the 12" square members are about 9/16" square. The diagonals are 1/4" x 9/16".
Finding an example was my "ah ha" moment from NG&SL Gazette. That gave me ties size and spacing, why guard timbers are used (not really for guards at all but to keep the ties spaced properly) and distance between the bents.
All those ideas about spacing your bents closer or further away to give false perspective is destroyed as soon as a scale train runs over it. I could see making the members smaller and lighter to give it a little "lightly funded" look. Some of the history books talk about the crews walking over the trestle before or after the engine for fear of going down with the ship!
Neil
Here are a couple of PDF's on building Timber Trestle Bridges. The author talks about building in the smaller scales, but a timber trestle bridge is built the same way no matter the scale. (OK, in 12 inches to the foot, it becomes a bit heavyer.)
http://www.blackbearcc.com/trestlebuilding_barrett.pdf
http://www.blackbearcc.com/trestle/press_rel_tj4.pdf
This author gives mery good info and data for construction in the garden.
http://www.btcomm.com/trains/primer/bridges/trestle/trestle.htm
Tom Trigg
Look in the April 2000 issue of GR, there is an article and template for building wood trestles. I model 1:29 standard gauge and added a fifth leg to my bents.
Hope this helps, Rob
Looking for some direction on the different sizes needed for the componets of a bent and if there is a site with a good set of plans.
Get the Garden Railways newsletter delivered to your inbox twice a month