When (historically speaking) would the first welded (as opposed to riveted) girder deck bridges have been seen on railroads?
Matthew (OV)
About the time I decided that rivets were more effort that I was willing to put in to a bridge?
Or, if you trust this web site…
http://theconstructor.org/structural-engg/plate-girder-bridges/2066/ said:
Plate girders became popular in the late 1800′s, when they were used in construction of railroad bridges. The plates were joined together using angles and rivets to obtain plate girders of desired size. By 1950′s welded plate girders replaced riveted and bolted plate girders in developed world due to their better quality, aesthetics and economy.
Now see, that’s the kind of answer I was looking for! I have just recently bought two bridges from a popular maker of such things for large scale. I specified dimensions, and was very pleased with what came out of one of the best packed boxes I’ve ever seen … but immediately after the FB post showing one went up, an HO scaler friend started asking about “lack of detail” (notably, rivets.) I’ve seen both types … and was hoping to get away with the “Welded” look simply so I wouldn’t have to figure out a source for scale-ish rivet heads, and then mark and attach them by the thousands … and then repaint, etc. And, I’ve seen the welded variety of both the deck girder and the round-end-girder bridge, so I know I’m not being too farfetched. I just wanted to make sure you didn’t have to get to 1980 before you’d see them… So, I guess I’ll believe that little blurb, and proceed! 
(Thanks again) Matthew (OV)
(http://freightsheds.largescalecentral.com/users/slatecreek/_forumfiles/bridge.jpg)
I should point out that both the dimensions and internal bracing style of this bridge were custom ordered, and never even blinked at by the fellow making the bridge. Just for fun, here’s the round end one too:
(http://freightsheds.largescalecentral.com/users/slatecreek/_forumfiles/bridge2.jpg)
That business with the 1950’s matches my memory of these things too. I was just a kid growing up then, in an area where I got to see all this engineering & construction happening first hand, and I noticed such things… by 1966 I was measuring bridges, usually girder-type as a surveyor’s assistant… and we were often replacing older, shorter, (and riveted) bridges over roads with longer (welded) bridges as the roads were widened.
Your HO friend was a victim of the fact that most HO model RR structures are based on a pre-WW2 mythos, as that’s when the majority of the molds used in HO were modeled after, steam era, often 1920’s era, when heavily riveted structures like bridges were first built, these structures had been around for decades and some became the model bases for the plastic HO counterparts that were mass produced and used nationwide in the post war era and still being produced today in N HO and O, so its a standard mythology that all bridges are riveted, all tunnels have cut stone portals and all stations look like the ones Atlas sold for all those years. And lets face it, a modeled riveted bridge DOES look better, in any scale, thats why they continue to persist in the model RRing world.
As for rivets, Micro-Mark sells those decal rivets that you could use.
Interesting, that last. Wonder if the O scale ones are large enough for my purposes…
Probably not…if you want rivets make styrene panels with rivets and insert between the uprights
I wouldn’t bother with rivets. BUT, if you REALLY want them, go with the textured paint route - the decals will be too tiny. You can almost see them on here, done with texture paint:
(http://www.jbrr.com/assets/images/IMG_1695.JPG)
Here, done with escutcheon pins. Can you see them? :o
Have just discovered a potential solution to the rivet problem. I have a co-worker with an embossing machine that will make just the right size rivets in metal foil in 4x6" sheets. Between those, and Phil’s I’m betting I can make the bridge look better. I was going to scuff and shoot in in black primer anyway to get rid of the shine … as long as I can bond the foil to the scuffed metal, I should be in good shape.
The only tricky part will be doing the bottom of the deck girder bridge and not squashing the rivets before its installed…
Follow Jerry’s lead and emboss the self-adhesive foil tape. It sticks great outside. I used it on my diamond crossing 3 summers ago to make the plastic rail sections look like metal rail and it is still hanging in there.
That will work as well Jon!