nl-2011-04-feature


Feature

Bridges . . . Bridges . . . Bridges . . .

by Ray Del Papa

 

As custom builders, one of our favorite challenges is designing and building bridges of all sorts for all scales. Many of these are hybrids where we kit-bash manufacturer’s offerings, and many are either completely scratch-built, or a combination of scratch-building and kit-bashing.

 

So, in many of our upcoming newsletter editions, we will often feature new articles on various prototype bridges and some of the custom model bridges we have done.

 

 

CENTER LIFT BRIDGES

 

One of my favorite types of bridges is the vertical lift span or the center lift bridge. A vertical lift bridge is built with two towers that guide the center span either up or down. The center span workings consist of steel cables which are attached to counter weights and a winch or hoist motor. There are also ample wheels and pulleys that the cables pass through, this makes for a very impressive bridge structure. The lifting of the center span allows for the passage of watercraft.

 

Here is the Steel Bridge in Portland Or. The center span is double decked, on the top deck motor vehicles, MAX light rail and streetcars pass, the bottom deck caries the railroad tracks and sidewalks. Photo from http://pdxmacs.com/gallery/bridgetown.

 

These bridges come in various sizes and are located throughout the country. Many different railroads used them to span navigable waterways. Therefore, no matter what railroad you model, if you need to span a navigable waterway, you can add one of these eye-catching bridges to your layout.

 

To my knowledge, there are a couple of generic lift bridge models available in HO and one in O scale. Not sure about N scale.  Nevertheless, with so many structural steel thru truss bridges on the market in almost every scale, there is ample opportunity to tackle a lift bridge model as a kit-bash/scratch-building project for those of you who are so inclined. A nice example of this approach is an HO lift bridge we recently completed.

 

liftbridge HO model

 

Or, for those of you in O scale, the most notable model (if you can find one) is Lionel’s operating lift bridge. Weathered up, this bridge looks nice, but if your demands are for prototypical accuracy, this offering will require a lot of modification.

 

 Hoist mechanism for a vertical lift span

Hoist mechanism for a vertical lift span” Joseph Elliott

 

 lift bridge in Cape Cod

 

Cape Cod Railroad’s center lift bridge at Buzzards Bay Mass. This was the longest center lift bridge in the world at one time. Photo from http://hubpages.com/slide/Cape-Cod-Canal-Railroad-Bridge/1123817 


from the April, 2011 SMARTT Newsletter

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