Hi. I've got about 3/4 of my 5' x 10' HO layout track laid (not counting 2 yards to be added last). The last section of main trackage, an upper level reversing loop, will include 2 Central Valley bridges in series: a 9-3/4" girder bridge followed immediately by a CV 21" truss bridge, with a pier where they butt together. On these CV bridges, the (code 83 in my case) rail can be added to the decks by squishing down the plastic tie spikes over the rail flange. I'm wondering whether it is better to unitize the 2 bridge decks together by using common pieces of flex rail. Otherwise, I figure I'd have to put rail joiners at the pier between the 2 bridge decks, which could contribute to vertical or horizontal kinking. I figure any vertical difference in the bridge shoes (I have not yet assembled the truss deck) can be handled with shimming one as needed.
Is there a preferred way to handle this junction?
Paul
Modeling HO with a transition era UP bent
peahrens Hi. I've got about 3/4 of my 5' x 10' HO layout track laid (not counting 2 yards to be added last). The last section of main trackage, an upper level reversing loop, will include 2 Central Valley bridges in series: a 9-3/4" girder bridge followed immediately by a CV 21" truss bridge, with a pier where they butt together. On these CV bridges, the (code 83 in my case) rail can be added to the decks by squishing down the plastic tie spikes over the rail flange. I'm wondering whether it is better to unitize the 2 bridge decks together by using common pieces of flex rail. Otherwise, I figure I'd have to put rail joiners at the pier between the 2 bridge decks, which could contribute to vertical or horizontal kinking. I figure any vertical difference in the bridge shoes (I have not yet assembled the truss deck) can be handled with shimming one as needed. Is there a preferred way to handle this junction?
I have done exactly as you propose. The CV truss rails were installed and left about 4" longer, the girder set in place and the trussbridge w/ the extra length rail was set carefully lining up the rail into the spike detail. then the spike detail was peened over. I made sure that I used a wood block support under the section not to damage the bridge/ shoes from this process. I use a bit of CA placed w/ toothpick to help hold the rails in place. Those small plastic "spikes" are fragile and want to make sure the rails are held firmly. Had an accident w/ the truss bridge when handling, rails got bumped and pulled out of spikes. The remaining rail was placed making sure it was placed beyond the abutments. Note, I like to anchor the bridges by doing this, it requires hand laid wood tie and spiking the bridge in place. This allows great anchoring but allows the bridge to be removed if needed. After a few inches of wood tie the Walther's/ Shinohara is continued. blending the wood to plastic tie weathering is the only issue.
Modeling B&O- Chessie Bob K. www.ssmrc.org
Bogp40, I'm not quite following. Did you use rail 4" longer than the 2 bridges combined (about 30-3/4") or did you just make the rail 4" longer than the truss and have a joint in the girder bridge??
I'll figure this out eventually!
Wherever possible, I prefer to use full lengths of stick rail. In addition to fastening the rail on the bridges using the built-in plastic tabs (I can't call them spikeheads with a straight face) I slide pieces of Atlas Code 83 flex tie strip onto the ends that will be laid on the `ground.' Since there are guard rail extensions to consider, I use the brown tie variety, even though most of my mainline track is laid on concrete ties. In my own modeling, if the rail extends well beyond the end of the bridge the brown ties yield to concrete at the ends of the guard rails.
To prevent damage while handling, consider arranging a temporary brace over the rails and fastening the bridges to it with twist-ties. That will provide useful stiffness and take the stress off those fragile tabs. Once the bridges are anchored to pier and abutments the brace can be removed.
Chuck (Modeling Central Japan in September, 1964 - with lots of bridges)
The CV truss was constructed first and when the rails were positioned they were allowed to extend 4" past the end of just that one truss bridge. . Note" before fitting rails both bridges were positioned adjusted and fit abutments, shoe shelf, etc. Then the girder was positioned. Now, when the truss was set in place, w/ rails the rails ran onto the the girder about 4". Those were set(peened) and the remaining rail laid making sure it ran past the abutment for the anchoring I mention.
There are so many methods of installing bridges, I just like to install by spiking that extended rail a few inches on the wood ties, The ties are glued in the fashion of normal handlaid, sanded to the plastic tie thickness and then stained. This also helps in adding guard rails of code 70 and allows you to extend them past the abutment as well. This allows for some very solid bridge anchoring , but is very easy to remove if nec.
Also with those rails running past the abutments, feeders are easily soldered up through benchwork. Since the double bridge had a rail splice on the girder one the rails had feeders @ both ends. You could do this w/ continuous one piece rail, however those rails attached to the truss bridge and extending about 12-14" could make setting the rails on the girder difficult plus the possibility of damage.
I use bridge track. It comes in three foot sections like flextrack, and the guard rail is included that you glue in. On two or more bridges that are going to be used together, I use one long section.
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.
I used the ME bridge track in 36" long sections for this application and trimmed the second one to fit. It has the code 70 guard rail as well (although not installed yet; bridges to be finished). On my CV bridge (in the background ) I ran the rail about 3-4 inches past the end and fastened them to the abutments.
-Bob
Life is what happens while you are making other plans!