Pier Girder Help Needed

[HAZMAT9]

Need some help. Don't know much about the Atlas Pier Girder bridge or any bridge for that matter, but am I supposed to place roadbed over that particular bridge or just a section of track? I placed the bridge in place and aligned it with the roadbed on each side of the cut out and find that the bridge w/ a section of track is lower than the roadbed and doesn't match up. If I stick in a piece of roadbed on the bridge w/ track on top it does line up....is this or isn't this correct? Just don't know enough about pier girders in general and this is frustrating me!!! Thanks, Steve[%-)]

[mononguy63]

Steve, you can't go wrong either way. You'll find real bridges where the track is supported directly from the steel deck framing and others that are fully ballasted and have weeds and underbrush growing on them. Generally speaking, newer bridge construction will be the former and bridges that have been in service for a few decades will look more like the latter.

[selector]

Lift your piers with something that you can cut and shape to look like a pier base. Even the cork might work. I would lift the entire structure until it supported the basic track and ties. You can hide such adjustments with paint, fake or real rocks, water, etc.

[HAZMAT9]

The pier girder isn't supported by piers themselves, the span has two notches on each side meant to attach to terrain on both sides of the bridge. Makes sense to prop the bridge up to meet the track and roadbed. The bridge looks more like it's meant to be used without roadbed since the structure is somewhat "see through" as you can see the bottom of the gultch through the ties....just never used one of these before, interesting style of bridge.

[nbrodar]

Just a note...the Atlas bridges, other then the pier girder, have the track built in. The bases are meant (I think) to line up with 1/4" roadbed.

In real life, the current trend is to use a closed bridge deck, and regular ballasted roadbed. It's a smoother ride, gives the trainman somewhere to walk, and limits the amount of crud falling on people and cars below the bridge.

Open deck bridges, where the track it secured to the bridge deck, are falling out of favor. There's always a jog in the track where it crosses the bridge, there's usually no provision for the trainman to walk, and stuff is continually falling on people below the bridge.

Nick

[bogp40]

Most bridges are supported on bridge shoes. These are anchoring feet located at the ends of the main beam/ girders and rest on the abutment shelf. If you add shoes or block the distance needed, the rail can be aligned.
Just a note, open deck and trestles use bridge ties which are much thicker (taller) than standard ties. Micro Engineering makes bridge flex track in 9' and 36' sections. It is avail in N, HO, and HOn3. The most common for HO scale is the code 83 that comes with code 70 guardrails and guard timbers, fire barrels and platforms. Very nice stuff and great people to deal with.
Bob K.