Roadbed

Religion rears its ugly head again

Roadbed, I've learned, is another one of those 'sorry I brought it up' subjects in model railroading. We know the methods: cork, foam (a la Woodland Scenics), Homasote.  I went with Homasote not because that was what I wanted (which was cork) but because I was convinced to go that route.  The reasons given were simple enough:

• At 1/2" thick, Homasote has a higher, more realistic profile for mainline running
• Once sanded and sealed, Homasote is stable for long-term operation
• Available in sheets, Homasote is more versatile to support mainline, branch, yard and terminal operations

As a cellulose-based material, the downside is obvious: Homasote is a f------ nightmare to work with! The three reasons for this are obvious: dust, Dust, DUST!  Milling it makes a lot of dust, and that fibrous crap gets into everything.  Sanding it makes a lot of dust, a finer fibrous powder that takes forever to remove.  Point made.

Even with the advantages elucidated here, which are as much justifications for my decision to use it as good reasons, I know many who would argue passionately for cork.  That could easily come to blows, so I just walk away.  I like cork - its look, feel, even its smell.  Again, I was convinced to go with homasote for the reasons above.  The best thing to do with a religious argument is not to have one.  Homasote was my choice, and now it's time to move on.

Using Homasote for roadbed

Laying roadbed:  The benefits of using Homasote come from a lot of work with it.  It comes in 4'x8' sheets, which need to be milled into planks and strips for yards and roadbed respectively.  Using my table saw with blade set at 45 degrees, 2 1/2" strips were milled for the mainline.  Wider sections were milled for sections of double-track mainline requiring crossover switches, as shown here:

In order to handle curves, the roadbed was notched on a mitre saw using a guard.  Following are the stages of Homasote construction.  Because the material is porous and uneven, sanding and sealing are absolutely essential to its successful use.  Here are the stages we followed:

Laying the roadbed on the mainline in single-track sections, showing notching, was done with carpenter's glue and temporary screws to hold the bed in place while the glue set and dried:

Double-track mainline was laid with parallel sections:

Turnouts were spliced into the mainline as shown at the middle left of this picture and here:

Sealing and sanding and sealing again: Once set, the roadbed needed to be sealed.  This was a lesson Brad learned from working with Homasote as a builder over the years.  Because it is so porous, Homasote can get distorted with changes in humidity over time.  In this case the Homasote was sealed with the cheapest interior latex flat paint I could find.  The key to painting is to choose a highly-contrasting color so that sanding reveals the imperfections more easily to be corrected.  With our 50+ eyes, that effect could not be underestimated.  Brad always insists on black for this purpose. I chose a dark chocolate (precise color doesn't matter, since the contrast is the aim) because it is built up earth (this argument is largely pointless, since it all will be covered up.  Ultimately, it was a capricious choice on my part), and the initial coat was put on generously. 

Next came sanding, which was needed to level the roadbed and remove any imperfections that could adversely affect operation.  Here's where the advantages of contrasting paint become evident.

Once satisfied that the roadbed was even, a final coat of paint was put onto the Homasote to seal it.

Planking for terminals and yards:  One advantage ofHomasote is that it comes in sheets that can be cut down for areas with a lot of track, such as yards, industry and terminals.  My terminal complex - the focal point of the layout - was set with sheets of Homasote on a deck of 1/2" MDF for maximum strength and stability.

This end view shows both the double-track bed set down, where custom crossover switches will be the lead into the terminal from the mainline. This track leads to a solid shelf 25' long for the terminal operation.  In front of this curve we wil plank over the section for the freight house complex, which currently is planned to be the first scene to be finished in the terminal zone.

For the yard, immediately below the terminal, the construction method was virtually the same.  In the foreground of this blurred image is the grade track.  Eventually, this grade will be hidden by the yard complex, which is planned to be both a working and staging yard for the mainline traffic on the layout.  As noted earlier, I don't care for grades even though my friends say they are 'cool,' because the city is the focal point of the operation.  To ensure the smooth operation of the mostly-hidden grade, we used the 30' straight of the west wall to set the most aggressive portion of the 2% maximum grade (wide 50" Radius curves at the far end solved the rest).

With the Homasote in place, sanded and sealed, we turn next to the track-laying part of the layout.  

Footnote: Homasote is a registered trademark of  the Homasote Company.  For more information on Homasote, see http://www.homasote.com/