|Written by Bob Canfield for Family Garden Trains(tm)|
|Written by Bob and Pat Canfield for Family Garden Trains|
The B&P Garden Railroad (B&P) - Part 2 - Building an HDPE Roadbed Infrastructure That Will Survive Las Vegas Summers
Note: This is a follow-up to Evolution of the B&P Garden Railroad Part 1. In addition, technical aspects of the following text will be best understood if you first read the Family Garden Trains Primer Articles regarding HDPE Flexible Roadbed by Paul Race, Bill Logan and Bob Zajicek.
If you'll recall, we decided earlier this year to have an outside O Gauge railroad, using a raised roadbed made from HDPE planks that are split and reassembled into a ladder-like framework (see Paul and Bill's HDPE Roadbed article for an overview). We also decided to preform the curves for our roadbed so we could squeeze a kind of double figure-eight into the space we had to work with.
After getting a load of HDPE lumber and preassembling many roadbed pieces, we began actual roadbed construction and placement in early September 2007. As we are writing this article, it is early October, and we’ve been at it for about five weeks. We have approximately 90 percent of the double mainline roadbed in place. The photo to the right was taken standing just south of the waterfall looking toward the north end.
Most of our preset curves have worked as expected, especially the five 180 degree curves at the North (3) and South (2) ends of the B&P. Making these concentric curves was accomplished by first making 180 degree, 40.5" (081) radius sections using our jig for curves.
Once the 40.5" radius is formed, we can use 3/4" Schedule 40 PVC pipe sleeves as spacers to maintain the 4.5" on-center track separation. This makes it relatively simple to make either the 45" (090) or 36" (072) radius curves, using the 40.5" curve as a jig.
When building an indoor O-Gauge layout, quality bench work is critical. We have concluded that, in our outdoor railroad, our roadbed installation, is our “bench work.” Consequently, we have spent a lot of time ensuring the integrity of the roadbed and its supporting structure. We hope to conceal most of the supporting structure with trestle bents and/or shrubs.
We are using PVC pipe as roadbed support because it is easy to work with, will not deteriorate if proper UV protection is applied, and is structurally sound. The way we are using it is a variation on the method described by “Split Jaw Products” for the placement of their G Gauge PVC Roadbed. Proper assembly of the 1.25" Schedule 40 PVC pipe sections also helps maintain the 4.5" on-center separation of the two mainlines.
When we started, we tried securing the PVC stanchions by cementing them into concrete blocks. Unfortunately, the finished concrete block with PVC was very cumbersome to handle. It also kept us from placing the stanchions as close to the existing concrete patio areas and block walls as we needed to.
As the photograph above shows, we now use the same PVC parts, but dig a footing and bury the PVC directly in concrete. First, though, we get the new pieces of roadbed connected and properly aligned - then we determine the PVC stanchion locations. This ensures that the vertical PVC pieces properly align with the roadbed’s openings.
In addition, when we laid our first sections of HDPE roadbed, Las Vegas temperatures exceeded 110 degrees. The HDPE softened, prompting us to use twice as many vertical supports as Bill Logan's plan ordinarily calls for. This reduces sagging, which probably isn't a big problem for Bill in Ohio. It also validates our choice to use PVC instead of HDPE vertical supports, which would have cost us a lot more money if we had to double them.
Construction has to be stopped for about four weeks due to previous travel plans. We hope to restart work before mid-November. Hopefully, we will be able to provide another update before the end of the year.
Still, the promised Christmas mainline for the Grandchildren may have to be set up inside on the carpet!
We hope our experience gives you some useful ideas and helps you plan your project more effectively. Please contact us through the Family Garden Trains Contact link if you have any questions. Just put the words "Questions for the Canfields" somewhere in your comments and Paul will forward them to us.
Bob & Patricia Canfield
Las Vegas, Nevada
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Note: Family Garden Trains™, Garden Train Store™, Big Christmas Trains™, BIG Indoor Trains™, and BIG Train Store™ are trademarks of Breakthrough Communications (www.btcomm.com). All information, data, text, and illustrations on this web site are Copyright (c) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 by Paul D. Race. Reuse or republication without prior written permission is specifically
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