I’m modeling the Soo Line and Milwaukee Road in Wisconsin (freelanced, but based on the real companies). Since i’m still in the building stage, I still have time to ask, “Does anybody know if either of these roads ballasted their bridges”. I’m currently building a bridge across a river, but it’s long enough that I would think that the companies would treat it like another strech of track. If anybody has info about their bridges, please sound off.
Peace
Since you are freelancing, you can establish engineering standards for yourself - within reason.
Ballasted decks can’t be used for the lift spans of bascule bridges, for obvious reasons. I seriously doubt that they would be desirable for the moving spans of lift or swing bridges (those tons of crushed rock would add considerably to the power needed to move the span.) Most bridges with ballasted decks are either deck girders, deck trusses or concrete structures that are little more than glorified culverts. On the opposite extreme are the huge viaducts like Starrucca, which were the earliest ballasted deck bridges - not surprising since the deck itself was stone (or, later, solid concrete.)
Chuck (Modeling Central Japan in September, 1964 - with lots of open-deck bridges)
Isn’t it just a matter of heavier counterweights? I can see getting into trouble with a span that lifts from one end at an angle rather than straight up. I’m unaware that real railroads glue their ballast down.
Mark
Note that I specified, “Bascule bridges.” That’s the family of bridges that tilt up at one end. If the deck was ballasted, the result would be something like emptying a dump truck.[#oops]
Another factor I hadn’t thought of. The rail alignment at the joint between the moving span and the fixed approaches has to be held to, at most, a few hundredths of an inch. If the connection is simply on ballasted track, it wouldn’t take much to knock it well out of tolerance.
Chuck (Modeling Central Japan in September, 1964)
Not sure we got off onto moving bridges, but anyway…except for the Mississippi River bridges between MN and Wisconsin, I don’t know that Wisconsin has that many navigable rivers that would require moving bridges of any type - and I can’t recall seeing any type of moving bridge that had a ballasted deck. I doubt it would work to keep the track in alignment, plus the issue of ballast falling and moving around and getting stuck in moving parts etc. would seem to make it a poor choice for a moving bridge.
Although I don’t have any specific examples of the Soo or Milwaukee using a ballasted deck bridge right at hand, I can’t see any reason why they couldn’t use one. I’m not sure about the “long enough” part though?? Except for a stone arch bridge, like the GN bridge in Minneapolis, my impression is that ballasted deck bridges are normally fairly short spans??
See if this link helps you:
The bridge that i’m building is a long river bridge (attaching two parts of my layout) that is stationary. It would be like a deck/truss bridge on large peirs. It dosen’t move at all, since it is large enough for the small boat to go under it.
Peace
My guess would be that wouldn’t normally be a ballasted deck bridge.
Hello “train freak,”
I don’t profess any expertise on either the Milwaukee Road or the Soo Line, but I may be able to help a little. A quick survey of photos of Milwaukee Road bridges in Wisconsin suggests that the Milwaukee favored open-deck bridges rather than ballasted decks. I had a harder time finding definitive photos of Soo Line bridges. Some of the Soo’s major bridges may have had ballasted decks – contrary to some posts on this topic, ballasted decks are used on some very long railroad bridges – but I wouldn’t hazard a guess as to whether most Soo Line bridges had open or ballasted decks.
The difference in construction, as you may understand, is that for an open-deck bridge special bridge ties are laid directly on the supporting beams or stringers. A ballasted deck requires construction of a trough supported by the bridge beams or stringers. Originally most of these troughs were timber, but concrete was used as early as the beginning of the last century if not earlier. Ballast is spread in the trough and ties and rails laid on top as if on the usual roadbed.
Ballasted decks make it easier to maintain an even surface between the approach tracks and the bridge itself, as the bridge track is easily raised as ballast is added.
So long,
Andy
So, if I were to be building it on a more realistic basis, it would just be easier to go with the unballasted deck? It seems like it would be less work in the “shop”, and easier to maintain[tup]. Thanks for all of your input on my problem!
Hi Ryan,
Depends on how you build your bridges, I guess, but my prototype, the Santa Fe, liked ballasted deck bridges and I find them very easy to build. Actually what I do is cut back my plywood subroadbed to fit inside the bridge structure, built the bridge deck trough on top of that using stained stripwood for bridge timbers, then build and ballast track across the deck as if the bridge wasn’t there. I go back later and add the beams or girders as necessary under the deck.
So long,
Andy
The Milwaukee did have ballasted deck bridges in some locations. Some of the large trestles out on the Pacific Extension were ballasted deck.
The early 1970s replacement bridge over the Des Moines River between Madrid and Woodward, Iowa was a ballasted deck bridge. Parts of that bridge have been used by the UP for the bridge replacing the Kate Shelley bridge.
Jeff
I guess which you choose could depend on whether you intend on scratchbuilding the bridge(s) or using kits?? A quick search of Walthers shows that Mirco-Engineering offers ballasted deck bridges in 30’, 50, and 85’ lengths. Looks like they’re the only ones in the HO catalogue.
The Wisconsin River was considered navigable, and many crossings of it were moveable spans. Might have been an old state law. The CNW bridge at Merrimac had a swing section, and many of the bridges on the MILW Prairie du Chien line had swing sections. Most probably didn’t get much use, if at all, but they had to be there.