I thought I had posted, but after scanning all of the replies, I found nothing. So here goes..

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This is a pair of metal G scale bridges. They fit the 5 rail GarGraves track perfectly. Top of the rail to the stair tread, 9' 8 1/2". So far, so good. IF there is a derailment, the wreck will be of Gomez Addams proportions.

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coach joe posted:

Gilly you're a very brave man.  What's the speed limit on that bridge?

I had a problem with my TMCC scale N&W 1218 A. It made a couple of passes over the bridge at full track voltage. Fortunately, the super-elevated 0138 and 089 curves on the outer main handled the speed with no problems.

Typical speeds are usually 35-45 mph max.

I returned to a section of temporary span to begin construction of proper bridges.  The two track overpass seemed simple enough...just fabricate a skewed through girder type to serve the purpose.  Simple couldn't be further from the truth.  As it neared completion ( more rivets to add ) the focus shifted to the major span.

The nature of the duck under area meant building a bridge without central supports, and because the track here is curved, a prototypical railroad bridge type does not exist in the real world.  Splaying the steel arch legs allows for ample support on the outside of the curved deck. 

Construction began by forming the deck from steel curtain rod "I" beams tied together with short pieces of wood.  Where the track crosses over lines on the other side it was simpler to continue the deck and tie it firmly to the benchwork.

The arches, again from curtain rod, produce the main support, and after a bit of maneuvering were anchored to the benchwork with screws.  A single screw at the top of each arch fastens them to the deck.  Notice the exaggerated lean to the inside arch, whereas the outside one is perfectly vertical.  Further stringers and latticework can now be added at leisure in a sitting position without interrupting train operation.

Finally, for now, here's a shot that emphasizes the built in superelavation to the curved deck.  String-lining here, a phenomenon that has yet to occur, could prove catastrophic.  Fingers crossed.

Bruce

 

Completely designed with your mind in mind.

n&wsteamfan posted:

If you look at the top picture. The elderly gentleman with the wheeled walker is the creator. 

Monumental!  A beautiful tribute to the " longest-span continuous bridge in railroad service in th U.S. "  With only 3 supports holding up 2 spans of 775' each, it relies on cantilever action to make the immense spans.

Anyone searching for info on all things in railroad bridges should get the Bridge & Trestle Handbook by Paul Mallery.

Bruce

Completely designed with your mind in mind.

n&wsteamfan posted:

 

We have had this beautiful all metal recreation of the c&o bridge in Sciotoville, Oh on display at our annual show in Portsmouth, Oh  

 

 

 

 

7D3CF9B3-6E57-47C4-8CF2-DC6D897E7FC3

 

 

 

Now that's a bridge!

Sean

Sean

 

TCA 14-6985#

 

Buy me a ticket on the last train home tonight.


brwebster posted:
n&wsteamfan posted:

If you look at the top picture. The elderly gentleman with the wheeled walker is the creator. 

Monumental!  A beautiful tribute to the " longest-span continuous bridge in railroad service in th U.S. "  With only 3 supports holding up 2 spans of 775' each, it relies on cantilever action to make the immense spans.

Anyone searching for info on all things in railroad bridges should get the Bridge & Trestle Handbook by Paul Mallery.

Bruce

He did a fantastic job!  I'll bet he feels happy it can be out on display for others to enjoy!

Bruce, Thank you for that great information and the plug for the Mallery book!!

 

 A work train slowly moves across 1,130-foot-long Baird Creek Trestle during the bridge’s construction in 1940 at Weyerhauser Co.’s St. Helens Tree Farm near Longview, Wash. The 235-foot-high structure was dismantled in 1961 when the railroad closed.       Weyerhauser photo

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