I’ve been eyeing some truss bridges, and the Atlas 18" Warren Truss one looks interesting and affordable…plus it comes with bridge track. But I was wondering, can anyone who has seen or has an Atlas bridge comment on whether they look toy-like? Such a bridge ends up being a prominent visual element, and I want to be sure it doesn’t look cheesy.
Second question for any bridge experts…for a span of like 50-70’ over a branch line, would the prototype use a short truss bridge or a thru girder bridge, or is it just a flip of a coin? Are there any operational guidelines for when a truss bridge is used, esp. if it’s a relatively short span like that. I’m thinking perhaps of a Micro-Engineering thru girder instead of that Truss…
Lastly, are all such bridges in the prototype painted black or gray(silver)? I want to be able to paint mone anotehr color, but never recall seeing such a bridge that isn’t either of those colors. Are there any roads that painted their bridges a different color?
I obviously don’t know a lot about bridges, besides that they look cool, and it’s time I start making some choices. Appreciate the guidance. Thanks!
I used two of them on my last layout. I thought they turned out well. Like most of the Atlas kits, it depends on how much time you put into it. On mine for example, I painted the walkways with a light tan color to represent wood, painted the railings light green, and then after assenbly weathered the whole bridge with powdered charcoal & sealed it with flat finish spray. BTW it’s made to basically snap together, which is nice because you can remove the top to do maintenance on the track.
I think the only real change I made is they have a kind of a splice plate that screws in place to hold the two halfs of the bridge floor together, IIRC when in place it left something sticking down under the bridge. I carved those parts off and glued the plate in place, so the bottom of the plate was flush with the rest of the bridge.
Since my new layout is going to be a double-track mainline, I don’t know if I’ll have a place to use the old bridges, but I wouldn’t hesitate to use one or both if the opportunity comes up.
I actually liked the Atlas 18" truss bridge… for some reason I think of the area near Sunbury Pa and maybe one of the bridges there. I actually plan to purchase one of these and work on the bench the technical problems of getting a good match to my kato track soon.
Safety…that may be because, according to the Atlas site, the birdge was “inspired by a prototype Northumberland, Pennsylvania”. Is that anywhere near Sunbury?
Sounds like their truss bridge is ok.
Hope to hear on some of the other Qs…like why a truss vs. a thru girder.
Northumberland… That’s it! I called it Sunbury anyhow. Easy to cross the river to the east bank and run on the flat towards I-80 instead of fighting the mountains on Rt15 (And a active scale house) =)
Anyhow… Truss gives ability to span long distances. The Girders give strength for about up to 100 feet or so… they really cannot make steel plate much longer than that. I understand the WW Bridge II being built south of DC has some of the longest plates possible.
So Safety, you nailed it!..the bridge is the prototype you thought of. Guess you’re ready for Double Jeopardy*…“I’ll take Bridges for $500, Alex…”* [:D]
And well, I take it then that a Truss bridge is more expensive to build than a Thru Girder? And that for a distance less than, say, 75 feet it wouldn’t make sense to build a Truss bridge? I think the gap I have would equate probably to about a 65’ span. I guess I could make it longer, 'cause i’m just getting into foam building mode.
I do like the look of those Truss bridges…they look awfully cool.
Seriously though, I like Atlas brideges, if you paint them, weather them and then be sure to add scenic details when you install them, they look great.
You can spend 25$ and higher on a Noch or Walthers or go Atlas. I agree with everything that’s been said. Detail and weathering and no one can tell. You put em’ out of the box on the layout and you get what you paid for. I use all Atlas in N Scale and used them in HO. Especially the plate girders with railroad logos on them.
I’m no bridge expert but I had to do a fair amount of bridge work as part of my construction project management consulting career. The type of bridge is governed by several factors, safety being first and cost being second (at least with good contractors. [:)] A truss bridge is much more expensive to build but it can carry greater loads over a longer span. A plate girder bridge is very strong but it is limited in span - about 50 feet unsupported is the biggest one I’ve dealt with. There’s also the issue of abutment conditions. It the bridge abutments can be placed on good solid rock, you can build a stonger bridge. If the ground is soft or, even worse, the grade to the abutment is man-made, you need a lot of concrete form work and pouring and usually need wing walls. In this circumstance, a plate girder bridge at its maximum span might be replaced with a truss bridge to give the required level of safety. Since you’re building a model, do what you think looks good. This is just some bridge trivia from the real world
In the city of Moose Jaw, Saskatchewan, which at one time was a major Maintenance point and is still a Division point for the CPR and is also the Canadian end of the Soo Line. There is a CNR bridge over the east end of the CPR yard, and it is a sight to behold. I think there is seven different types of bridge decks used here. It is if they just had a lot of spare units and hooked them all together to span a creek the yard and a small lake. So I believe that whatever you decided to buld there is probably a prototype for it somewhere.
I’ve got one of the old “chord” bridges, 18 inches long and similar to the current through truss bridge. I painted mine “moss green,” which is a dark color and looked very good. I added a whole bunch of rust, and then painted one corner bright, new silver. I added some painters and scaffolding and got an interesting scene.
Like any kit, I think of what comes out of the box as a starting point. I added Caboose bridge abutments, too.
As for colors, I have seen aluminum (looks like, but isn’t, silver,) black, several shades of green, tan and my prototype’s favorite, oxide red. In some cases, the color is dictated by the local community’s idea of appropriate appearance, especially if the bridge crosses a significant thoroughfare or the City Park (or is clearly visible from same.)
The, “Painters at work,” scene can be done in many ways, from just started to almost finished to spot cleaning and priming before an overall repainting. For the morbid, a partially collapsed scaffold, emergency response vehicles on scene… (My daughter is a first responder - firefighter/paramedic - which may influence my thinking.)
An inexpensive kit can become a masterpiece or a more expensive model can end up looking toylike. It all depends on detailing, painting and weathering.
As for the choice between through truss and through girder, there is also the matter of clearances. A through truss doesn’t lend itself to the movement of oversize loads that will pass right over a through girder without a hiccup. Of course, the preferred design, if possible, is a deck bridge. Underside clearance is usually the deciding factor.
I think Altas bridges look great, as long as you paint and modify a bit… below is a bridge that uses an atlas girder truss… look good to me, but you be the judge.
Here is a closeup of the Atlas portion…actually 2 of them spliced to make a longer span…
And here is a silver colored bridge… I like both silver and black…
Anyway, just my thoughts… these bridges look great if you put real wooden ties and guard timbers, guardrails, etc. Have fun!
Nope, they’re not cheesy at all. In fact, with a little painting and weathering, they’re pretty darned good looking. See my icon in the corner, I’ve got one of my Yellowstones crossing an Atlas bridge on Yuba Summit–one of two 'twin’s in the same area. I’ve also got several other Atlas bridges on the layout (I have fifteen bridges total, some kits, most kit-bashed) and the Atlas do the job pretty well for me, IMO.
You’re welcome. My son is a structural engineer and would probably disagree with some details but I think it’s close enough for government work. [:)]
Brian, nice looking work on those bridges. The detail on the silver painted one is especially good. The only thing that makes me cringe (from a professional viewpoint, not because of your work) is that brick abutment. Brick would never be used for abutments, especially one as large as the one you’ve modeled. It doesn’t have the structural strength and there’s no easy way to anchor it to the vertical surface behind it. Nobody but a few nerds like me would notice and it and it looks nice so I wouldn’t change it. Well, I would because my son will see it and I’d have to listen to half-hour lecture about the correct uses of brick. [:-^]
I remember reading the through girder bridges were pretty expensive to construct and maintain compared to deck truss and deck girder bridges, and you had the clearance issues as well. Basically, as I recall, real RR’s wouldn’t use the through girder bridges unless there was some sort of underside clearance issue, such as a road, waterway that is subject to frequent flooding or other clearance issue (boats), or the like. For a short span, a deck girder bridge would be the most likely logical choice, assuming no underside clearance issues… A short deck truss would probably be overkill. The deciding point was around the 85-100 foot mark, at which poing the truss bridge would probably be cheaper, especially if you had major issues with building any center abutments (too tall, in a deep waterway, in soft mud, steep terrain, etc.) It also depended on how strong the bridge needed to be. I won’t get into that now (for lack of my reference, among other reasons). Post another question (or email me) if you want more on that issue.
If I recall my structural engineering courses correctly, part of the issue with the type of bridge, besides cost, is the abutments and/or footings for the span. The SF/Oakland Bay Bridge is a good example, part of it is a suspension cable bridge and the other part is a cantilever structure all dictated by the soil conditions at the bottom of SF Bay.
I would go with a deck girder bridge in a flash, but the problem is one of clearance; there’s a main line under the bridge, over which a branch line rises up to a mountain gap.
I guess for a short gap, like my 65’ one, a thru girder seems the choice. I may lengthen the gap and go with a truss since I’ve got a jones to use one. [;)]
Good news is, my abutments will be built on solid rock. I’m planning cut stone abutments.
I’m thinking of the silver bridge, which I’ll weather to a rust color. Not too rusty, since inspectors wouldn’t allow that in reality.
