One of our late friend, Bob Hollowell, gifted me a Pratt Truss bridge he had built years ago and no longer used. I have now used it on two layouts.
I purchased the ME bridge track segments, I think they're about 28" or so long, forget. I wanted to be able to remove the bridge because it was one of the first items I installed along with the roadbed and tracks, and it crosses over a nether track...I had to do all that scenicking under it.
So, I have two tracks comprising bridge track, meaning eight ends that need joiners. It works well, provided you don't remove and replace the joiners 20 times. Or, you'll have to replace them for a tighter and cleaner fit and interface for the various rail ends. But, it works.
Not my usual standard for quality, but I think it will suffice to give the general gist:
I have Central Valley truss & girder bridges in series with a middle supporting pier. Those kits have ties where rail (I used code 83) is laid on the ties and little plastic nubs are peened (smashed) across the rail web. I added some CA at points as well as the peened nubs hold was a bit marginal.
To your point, I used 3' flex track rails longer than the length of the 2 bridges. I liked the idea of not having a joint to align between the two, which could have more of a tendency for a horiontal and/or vertical kink (at the joint), due to any misalignment of each bridge. With the continuous rail, any misalignment tendency tends to be a minor curve vs. a more severe kink that can occur at a rail joiner. Similarly, I continued the rails a couple of inches past the bridge ends (with added ties) much like Kevin's photo shows. That allowed the rail joints to be on the adjacent, flat cork roadbed rather than above the subroadbed / bridge abutments interface, where (again) I prefererred not to have a rail joint.
As I now have ballasted and am adding scenery, I am realizing how "permanent" I am making my layout. It is too large to be moveable, so if we move I will be salvaging selective items. The bridges would be one target, like structures. As described above, I was more interested in best installation and reliability and did not much consider removal difficulty.
HO Ogden Meet (2) by Paul Ahrens, on Flickr
Paul
Modeling HO with a transition era UP bent
Hello All,
kenbenWhat's the standard rule-of-thumb?
There isn't one.
How long is the bridge in actual inches or scale feet?
As others have posted, How "permanent" do you want it to be?
On my pike I have a kitbashed span that crosses the track below at an angle. The approaches to this bridge are curved. The actual span is straight.
The bridge track extends about 1/2-inch on each end to tie into the curved sections. This 1/2-inch also allowed me to build in prototypical guard rails with the proper extensions.
Yes, there is a joint in the center of the bridge track because I use sectional track.
If you use flex track- -which comes in 36-inch lengths- -you should not need a joint along the length of the bridge track.
Because of the placement of this span on my pike I do not need it to be removable so I used standard rail joiners. But, I did not solder these joints- -just incase I need to remove this span for upgrades.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
I have been using Micro-Engineering bridge track for my past few bridge installations, and I love it.
I cut the bridge track just a little long, then I replace the ties off of the bridge section with plastic ties cut from Atlas sectional track. I just put the rail connections where they end up.
-Kevin
Living the dream.
Is your layout permanent or temporary? If temporary, can you live with two bridges joined together in your future layout?
Henry
COB Potomac & Northern
Shenandoah Valley
I have a grider and truss bridge in my new layout. Is it best to add track to just the bridges (creating 4 rail joints on each) and then tie into the track on either side OR just run the track straigh through the bridges (which would make them perminate)? What's the standard rule-of-thumb?
THX