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Central Valley Pratt Truss install questions

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  • Member since
    July 2011
  • 81 posts
Central Valley Pratt Truss install questions
Posted by CharlieM90 on Friday, August 19, 2011 8:49 AM

Looking for some comments if any one has experience with building/installing

I have a Central Valley Pratt Truss bridge I'm nearing completion and install. I'm wondering about the bridge floor. The upper Truss is designed to be "lift-away" from the floor for ease of maintenance/cleaning. But what about the bridge floor?

Photos in the instructions show an install with modified rail joiners so that the bridge floor can also be lifted out. My concern is with electrical contact and alignment over time. I'm thinking of soldering the rail in and making it a permanent install for the bridge floor to avoid alignment/electrical problems in future.

Can anyone offer insight? Anyone done it one way and wished you had done it the other? Any caveats?

  • Member since
    January 2007
  • From: Eastern Shore Virginia
  • 3,290 posts
Posted by gandydancer19 on Friday, August 19, 2011 2:41 PM

I built one and installed it last year.  I also kept the truss section separate from the floor.

I make all my bridges removable.  I make sure they sit even on the piers and the track on the bridge is level and even with the approach tracks.  I power feed both approach tracks, and then just slide the rail joiners in place. 

I installed the Pratt in one piece even though it could come apart.

So far I haven't had any problems.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

  • Member since
    February 2004
  • From: Knoxville, TN
  • 2,055 posts
Posted by farrellaa on Friday, August 19, 2011 3:21 PM

I built mine a couple of years ago and soldered the rails in place, but left the top structure removable. Works great and don't have any problems with the track. The bridge does flex some when my larger locos go over it but not noticalbly. Great model. I also replace the 'wires' with real .015 wire, much better looking.

   -Bob

Life is what happens while you are making other plans!

  • Member since
    November 2002
  • From: US
  • 2,455 posts
Posted by wp8thsub on Friday, August 19, 2011 6:27 PM

I didn't see a point in removing the track, so only kept that part separate until after my bridge was painted.  I initially had the truss removable but eventually glued it in place also to ensure the whole structure remained rigid and didn't flex.  The model has been around for about 20 years and three layouts and hasn't given me any maintenance hassles assembled this way. 

I like to have bridges removable from the layout for scenery construction, and don't like rail joints right at the end of a bridge to avoid the potential for a bump in the track as much as possilbe.  I add rails extending for several inches in either direction, and finish spiking those onto wood ties after the messiest parts of the scenery are in.  Until that point, the joiners are kept loose and the rail off of the bridge itself gets only a minimum of spikes to ensure reliable operation.

Rob Spangler

  • Member since
    January 2004
  • From: Canada, eh?
  • 13,375 posts
Posted by doctorwayne on Friday, August 19, 2011 9:00 PM

I built mine several years ago and left the truss assembly removeable.  I also substituted .015 music wire for the braces, attaching it at the top and letting the lower ends sit, unattached.  This was to avoid deforming the truss members.  I also build my bridges to be removeable, with unsoldered rail joiners keeping everything in alignment.  I did drop feeder wires from both ends of the bridge and from the tracks at both ends (I don't use a bus wire), but haven't yet had need to connect them.  Everywhere else on the layout, all rail joiners are soldered.

The five spans shown below (the closest one is obscured by trees) lift-out together, as a single 53"-long unit:

 

At the time of the original installation, there was no "water" in place:

 

Wayne

 

  • Member since
    January 2009
  • From: good ole WI
  • 1,326 posts
Posted by BerkshireSteam on Tuesday, August 23, 2011 7:30 AM

You know, I just seen one of these last time I was at the hobby shop in N. Now I think I will get it for sure. Oooh the wifes going to complain. Last I told her I was going with the 'bigger' trains not the N. Then again maybe she will be okay, she did start call the 'small' trains by N.

  • Member since
    July 2011
  • 81 posts
Posted by CharlieM90 on Tuesday, August 23, 2011 9:19 AM

BerkshireSteam

You know, I just seen one of these last time I was at the hobby shop in N. Now I think I will get it for sure.

Heh.

 

I have a second one to build and find a place for. I tend to buy things in "2s" so that if I like it, I have another to play with. And if I mess it up...I have spare parts.

So many of this type (or ones that look like it) in the area I'm modeling (Cumberland Plateau) that several will, I think, serve to help capture the "look and feel" of the area.

Plus, they're fun to build.

 

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