Benchwork - Roadbed
Middle school model RR: cutting roadbed
Maybe it’s just the mild climate here, but I’ve never had any problem with sagging roadbed when I’ve used a glued-together sandwich of Homosote and plywood over 16” spacing between risers. Even when I’ve used ½” plywood it always felt plenty stable, even overkill.
So for light weight and ease of handling, I decided to risk being scolded by wiser and more experienced modelers and used ¼” plywood on this layout. I admit that I’m nervous about having to eat crow, but so far I’m not seeing a problem.
Helpers on Helix
Hello all - first post on MRH.
I want to build a helix (major statement!) - on an existing layout. I have it basically designed. It is an oval shape, each loop about 248 in. long, 29 in. radius one end, 25 in. other. It is right at 2%, so roadbed-top to roadbed-top separation is almost 5 in. Except for the first 1/2 loop, the helix will be entirely hidden. I'm not in favor of little openings/windows along the grade - I just can't figure out how to make them look right. Maybe LED's or CCTV, maybe.
Middle school model RR: cookie cutter roadbed
Jackfull gets a bonus point for resourcefulness.
Did everyone else finish their homework? Any questions? Some of you got stuck? Does this help?
Some of you probably remember the Pythagorean Theorem: the sum of the squares of the legs on a right triangle equals the square of the hypotenuse. Which means:
Middle school model RR: spline-drawn curves
The actual math behind the cubic spirals of railroad curves is not normally a part of the middle school curriculum and I have no intention of drilling kids into proficiency with them. On the contrary. But I do try to illuminate the mathematical aspects of their everyday experiences and help them see how those connect to fields like engineering, economics, music, or whatever.
Re-visiting the Lift Out Bridge...
Today I finally decided to tackle something that has been bothering me for awhile. The lift out bridge that connects the centre peninsula to the northern side of the layout has been not quite right since it was converted from a swing up to a lift out.
Great Works weekend
A great weekend of work. The crew has finished up the last of the bench work with fascia going up in the last areas. Cabinets being finished with doors hung and painted.
Homasote Spline Work
This is the crux of it. If this step isn't done right, it'll never be right.
Per Jeff Otto, three 2 inch strips on end, screwed together with drywall screws....no glue, no need for clamps. Handful of 8 foot long strips cut in half for borders on each side to attach scenery to.(Jeff suggests the borders cut at a 30 degree angle for a ballast profile)
Did the entire mainline in 4 hours....but thought better of it and went back to make sure it's all right.
Simple Switch Control
Here is what I will be using to control my switch's on the layout. In these photos you can see the parts that I used and how I used them. All these parts I got from my local hardware store, electronics store and a hobby shop that deals with remote control airplanes.
Middle school model RR: benchwork installed
It took a few more weeks but eventually we had all four sections complete and installed. Because the layout had to be lightweight and removable my benchwork design relies on the interaction of many components for rigidity. For example, the backboard is made from a 12” wide strip of 1/8” masonite which contributes a considerable amount to the stiffness when screwed to the panel frames. To protect the blackboard against which the backboard rests I had the kids install self-stick foam weather stripping.
Middle school model RR: cutting gussets
The wheels were in motion now and all three sections of my seventh grade math classes were hard at work on their respective components of the benchwork. In addition to the attention that they gave to their own parts of the project they were of course very interested in what the other sections were doing. Since everything took place in the same room it was natural for them to examine each other’s works in progress and think about how the various parts would come together. A very stimulating balance of mild competition and collaborating towards a common goal emerged.
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