A few guys here have asked that I start a thread about the unconventional roadbed I am using on my N scale Allegheny Eastern layout. I have written about it on my blog, but it was suggested it should also be shared here.
Not exactly sure where to start, but here goes...
The Allegheny Eastern goes through revisions more often than I change socks. I am constantly trying new ideas in design and construction. If I find one that seems to work very well I'll often redo the entire layout. I'm not above starting over from scratch if need be, though these days this happens less and less. The general design has crystallized. The last major changes are in process (famous last words).
I've tried some rather unorthodox ideas in planning and constructing the layout. One of the materials I've tried several times is extruded styrofoam. Through much trial and error I developed a construction method for roadbed I tend to call styrosplines. This is the construction I am currently using on the All East. Although I was using a plywood and foam lamination based on traditional "cookie cutter" construction. I found myself using and entirely different construction when revising a small section of the layout. It was this revision that caused me to rethink my approach and set me off in a new direction. I liked the results so much that I started rebuilding all the roadbed in the same fashion.
It's pretty simple and straightforward. Using a straight edge and a razor blade from a utility knife I cut 4' x 8' sheets of 1/2" thick styrofoam into 32 strips 1 1/12"thick. I cut along the sheet so the resulting "splines" are 96" long...
These splines are very flexible horizontally, like flex track. They can be formed into long graceful curves. They can be curved into a radius of about 12" before they will snap. I suppose if great care was taken, they could form even tighter curves. I prefer wider curves as they look more realistic. On the Allegheny Eastern the minimum radius for mainline curves is about 18".
I have found that the splines must be used in sets. For one track, two splines laminated together are exactly the right size. Two tracks requires four splines, and four track, the typical arrangement on the All East, requires eight. To make any of these configurations I simply laminate the correct number of splines together using a foam compatible glue. I personally use Aileens Tacky Glue from a local craft store. It's flexible, and holds tight. It's like white glue but dries to a rubbery consistency.
I usually lay out the roadbed ahead of time and use coffee cans full of bolts (and/or paint cans) to hold it in position until I get an alignment that suits me and follows the general lines of the track plan...
I then begin gluing up the splines. On my four track mainline I glue up the first pair and let the glue set...
I find that laying the first pair as far as I am able is the best method of constructing the roadbed. This primary layup goes pretty quickly. I can do the entire length of the main grade, about 33 or so feet, in a few hours...
This creates the general arrangement of the track for all the other splines to follow. Each additional spline is then glued to the previous one to form a horizontal lamination...
One other reason I try to complete an entire section is the fact that the splines never line up length wise. They all start out 96" long but as each spline gets further from the center of whatever curve they form they wind up with staggered ends...
This "offset" gets more prominent the longer the roadbed gets. What starts as a half inch after the first curve can grow to a foot or so at the far end of the roadbed. This offset is actually a good thing, The more staggered the joints are, the stronger they will be after the glue sets. In fact, it's a good idea to stagger the splines as much as possible. It's rather like laying boards in a hardwood floor. You do not want the joints to line up.
There is one other odd thing to way I lay road bed. Following the conventional way you would extend the roadbed a little at a time, placing risers at regular intervals at certain heights. On the Allegheny Eastern I build the road bed first and then elevate it to create the desired grade. The splines allow me to create roadbed that is essentially one long laminated piece. In creating grades I start from the top and install and adjust risers so I can maintain a smooth slope to the bottom. This does not mean that I "eyeball" the incline. I know ahead of time how high the grade will go and how long it must be to maintain the desired percentage. The All East climbs to a height of 106 scale feet as it winds its way up the east slope of the Alleghenies. The resulting grade is about a scale mile long at a constant 2%.
I think photos can reveal more of the process than all the words I can ever type. We'll follow the unfinished roadbed from Tunnel Hill down to BO tower...
This helix represents the west slope of the Allegheny Mountains. It's a 100 odd scale feet high overall and a scale mile or so long.
Tunnel Hill is the highest point on the All East and the summit of both eastern and western grades. It's also the location of the loop where helpers turn around and head back down The Hill.
Remington, where the four track main splits in two to pass through the tunnels at Sugar Run Gap.
At Kittanning Curve the Allegheny Eastern four track mainline loops like a giant horseshoe around the Burgoon Valley.
The bottom of The Hill at BO tower where helpers are assigned to trains for the climb to the summit.
The photo at BO tower shows a transition from plywood table top to the styrospline roadbed. This is about to change as the entire mainline is being reconstructed with splines. The plywood under the Llyswen yards and certain other areas will be replace with 2" thick extruded styrofoam sheets.
The ongoing (and rather insane) saga of the construction of the Allegheny Eastern can be found at
http://kelticsylk.blogspot.com/
