bridge trestle question......

[geepers]

hello all, im wondering.... on the real life curved trestle bridges, do the engineers build the bents to curve with the deck? or are they still straight? the reason is, on my wooden curved trestle, im kinda confused as to how to install the bents. i have another line crossing under the trestle, so i need to be careful on how i angle the bents so they clear the lower track work. any suggestions are welcome. thanks![:D]

[dehusman]

The bents would be perpendicular to the centerline of the track normally. If there was some sort of river channel or tracks under the trestle, then they might have a short span deck or plate girder bridge, with the bents arranged to clear the channel or tracks.

Dave H.

[selector]

And, no matter how it 'was done', I have seen very nice layouts where the modeler turned the bents enough so that the tracks or obstacle crossed was not obstructed (wouldn't make sense, otherwise). However, the bents that are adjacent to the lower tracks/water will have to have a wider profile as the angle varies from perpendicular to the rail axis. Also, if the span between those bents is much longer than standard, they would need some heavy diagonal bracing to keep them rigid, and maybe some additional lumber under the ties above them to support the track and train.

I have a grade rising up the side of my mountain that passes under a trestle coming out of a mine's hopper car loading station on which ore cars are pushed and then towed back to be loaded in succession. As the lower track is curved passing under the trestle, and enters at a slight angle (15 deg?), the outer span is necessarily wider, but very little. Maybe I just got lucky, but I can even get my Hudson up there without contact...not that a J1e would ever be used on a mine spur.

[7h9h_]

you can make curved bridges

[jkeaton]

I know I'm going to end up with some curved trestles, probably with short spans to cross a river or another line of track. I'm assuming that the curve of the track continues through the short span bridge - and that the track wouldn't suddenly go straight, then cuve again. But does anyone have a photo of a model or, better, prototype example of this? I must admit to being visual - would rather see it than read a description of it.

Jim

[Adelie]

Kalmbach has a book on model railroad bridges and trestles that, if my memory is right, shows a plan for building them on a curve. It might be worth checking out somewhere.

[selector]

You can curve the track constantly, or tighten the curve, or loosen it, as you need to. Just try to keep the bents straight, looking at their profile from the top and sides, but orient them so that the top is at 90 deg to the axis of the track at the point where it supports the track.