The relationship of benchwork, riser height, and scenery depth is often discussed on the model railroad forums. The LK&O takes a bit of an unconventional approach to this relationship and so some explanation is warranted.
Typically, benchwork is on a single plane (top of the benchwork rails and crossmembers). The plane is below the lowest scenery elevation. Risers are used to elevate the track to the desired height. Scenery contour then fluctuates in height above and below the track level. The maximum depth of scenery is the benchwork plane but can go upwards as high as vertical space will permit.
While simpler to build, single plane benchwork sacrifices valuable deck-to-deck spacing in areas where deep scenery is not needed. Most of the LK&O route is in relatively flat land – Brittain Yard, a section of Market St. in Akron OH, the rubber factories, and Lapeer. Deep scenery is not needed in these areas. Small streams, a few culverts, and the occasional ditch are all that require below sub-roadbed elevation. And then, not very much. The sub-roadbed in these areas on the LK&O is set on 2″ risers. 2″ in HO scale = 14′ 6″. More than enough depth for culverts and ditches.
On the opposite end of the railroad is Kitzmiller deep in Appalachia. Here, the rugged mountainous terrain requires much more scenery vertical depth hence a lower benchwork plane and taller risers are called for.
To have the best of both worlds, maximum deck-to-deck spacing and deep scenery where needed, the LK&O is built at three different benchwork planes. The Akron area benchwork plane is 53″, six inches higher than the benchwork plane at Kitzmiller at 47″. A transitional benchwork plane at 50″ (3″ below Akron and 3″ above Kitzmiller) is used in the Metikki Mine area. The LK&O benchwork is stepped. This way I have vertical scenery depth where I need it and additional deck-to-deck separation where deep scenery isn’t needed.
Additional vertical scenery depth was needed in two places where the 2″ risers are used – the river in Akron that intersects the fascia and the river in Lapeer that also intersects the fascia. I did not want to sacrifice deck-to-deck spacing under the entire Akron/Lapeer area just for two small rivers. But the rivers need more than 14′ depth. So, in these two areas the benchwork rail is cutout across the rivers which sit below the benchwork plane and in between crossmembers. The cutouts add an additional 2″ of depth for the rivers. This makes the riverbed 29 HO scale feet below the sub-roadbed. This is enough depth to make a railroad bridge over the river look right. Steel strapping will reinforce the benchwork rail in the cutout areas.
Another vertical space saving technique is employed in the staging area on the lower deck. Here, there are no risers at all. The sub-roadbed will be attached directly to the crossmembers. This adds an additional 2″ of space. There is no scenery in the staging area so no depth below sub-roadbed is needed. The remainder of the lower deck is rolling countryside and has the same 2″ scenery depth as most of the upper deck.
Here you can see the benchwork elevation changes.
There is one unique exception to benchwork plane on the upper deck that required lowering. The bridge over the River Styx is a signature scene on the original AC&Y railroad. It is the long bridge over a deep valley that every model railroad must have. 🙂 The LK&O is no exception. The River Styx scene will look cool. Can’t very well have the river only 14′ below the bridge. The River Styx bridge sits atop towering bents. To facilitate the deep valley I greatly lowered the benchwork just in this area. All the way down to 41″. The River Styx valley can now be 100 HO feet below the bridge. Cool. There is no lower deck under this part of the layout so depth was no issue.
Well, there you have it. My thought process behind the benchwork. Now, whether or not it works as planned is yet to be seen!