Has anyone modified any of the commercially available bridges from the standard straight/square format to a skewed/angled variation please?
Pics of any models and/or real skewed bridges similar to the models (to provide guidance) would be really useful.
Thanks
[:P]
Here you’re:
Wolfgang
Prototype:
Mine:
On the ATSF:
On the SP:
Here’s a skewed highway bridge I kitbashed from 2 Atlas RR truss bridges. The design includes foreced perspective, and the brigde is more narrow near the bus than it is at the front edge of the layout. Beyond the bridge, the road keeps getting more narrow.
I sure miss those Burma Shave road signs. No thanks to Lady Bird Johnson.
Mark
Great examples [^] Terrific models [:P]
Any moreexamples anyone? [:)]
This Walther’s double track truss bridge was modified by a club member. Portions of a second kit and some Central Valley girders and misc plastruct were used.
I have a couple shots from below a deck girder bridge but not a skewed one.
Not sure why there are loose boards there. I presume they are used by workers to help their access to the bridge interior for inspection/repair, and vibrations have moved them since last used.
Mark
Traincat sells some beautiful photo etched skewed bridges: http://traincat2.com/
If your skewed bridge has an open deck so you can see the below-track steelwork, the cross connections (except the skewed ones at the ends) should be at 90 degrees to the main girders or trusses. The ends will have various special arrangements, in part depending on the type of bridge and the skew angle. For a DPG, often the last 90 degree brace frame will suffice with no skew connection required. Trusses and TPGs often have a skewed floorbeam for the stringers to tie into, but I have seen examples where the stringers rest on the abutment instead. (The floorbeams connect the outside girders and the stringers run between the floorbeams to support the ties.) The trusses themselves may be altered at the end portals, with the diagonal member coming down at an odd angle to the abutment. This will depend on whether the top portal brace is skewed or at 90 degrees.
Because usually the interior floorbeams or braceframes are at 90 degrees, you should try to make the vertical posts in a truss, or stiffeners on girder bridges, match on both sides. Bridge engineers will design appropriate spacing to achieve this; working with available models may mean turning a blind eye is required.
John
At a club I once belonged to (on an Air Force Base since closed) we had a skewed Atlas pony truss. It had been built by assembling the trusses offset by the width of one panel, then cutting the floor at an angle and dummying in new, skewed, floor end beams at both ends. The prototype would have done the same, since the crossbeams in the floor structure are supposed to line up with the bottoms of the main side truss members, for maximum strength.
Deck girders are a lot more forgiving, since the main girders carry the weight directly and the connectors don’t have to deal with vertical loads.
Chuck (Modeling Central Japan in September, 1964)
Here’s a skew bridge for you:
and here’s a lot more info on it: http://explorepahistory.com/hmarker.php?markerId=660
–Randy
