Layout Progress Report #12 as of 04/18/2010

It's been a busy couple of days on the Cahaba Southern, as the upper main level benchwork was started and completed.  Most of the major wood cutting work had been done several months ago when the lower level was made.  At this point all that needed to be done is for the beams to be cut to length and a few pocket holes to be drilled, as the cross-members were ready to go.  The other part that required some work is the benchwork around the helix, as it required some angled cuts and some fitting around the helix itself.

The first piece of framework is mounted to the walls.  As can be seen in the picture support blocks have been put in place around the walls to help support the framework.  In addition to these blocks which are mounted to the wall studs the framework is attached to the wall studs as well with 3 inch screws.

The second piece of framework is completed and mounted.  It is secured to the wall, the first piece of framework,  and the framework around the helix.

The following picture shows the helix framework in a little more detail.  3 of the outside helix support rods had to be shortened as they were in the way of the framework.  Small wooden spacers were cut to support the helix at those points where the rods were shortened.  I'm sorry that I didn't take any pictures as I was doing this, as I plain forgot too since I was so busy figuring out these adjustments!  Sometimes even the most well-thought out plans require last minute tweaks....

The third piece of framework is in place.

Then the fourth and final piece of framework is installed.

That went quick!!  I guess after the weeks of working on the helix there was some renewed energy to work on the Cahaba Southern again.  Next it will be time to work on the curved backdrop for the main level, as well, as getting some lighting in place for the staging level.  Until then.......

How-To: Laying & Joining Flextrack in a Curve

Laying and joining flextrack on curves is something that can be daunting and frustrating for beginners as well as experienced model railroaders alike, but here is the technique that has served me well over the years. The following pic shows a piece of Peco 55 flextrack in place on a 17" radius curve on my helix, waiting for the next piece. First things first is always put the movable rail on the inside of the track.

When putting the movable rail on the inside that inside rail will end up being longer.

Using a cutting tool (in my case a Dremel with flexshaft and cutoff wheel) I then trim the inside rail to match the length of the outside rail. You can see the red mark of where to cut the rail.

After the first piece is trimmed to length I lay the second piece out, movable rail on the inside, with a radius close to the final one.

Now the second piece needs trimming on the inside rail.

Once the second piece is trimmed, attach the two rails together with rail joiners.

Next solder the 2 pieces of flex to each other and the joiners.

Here is the soldered rail.

A little cleaning up along the top edge and inside edge with a needle file to remove any stray burrs, giving a perfectly smooth joint.

Now pull the track out of the way towards the inside and put down the adhesive latex caulk to hold the new piece of track.

Smooth out the caulk and set the new flextrack piece in place, tapping in some thumbtacks to help hold it. The caulk will turn clear when dry.

All done, or as in my case: Lather, Rinse, Repeat!!!  

Layout Progress Report #10 as of 03/15/2010

Just a quick update:  The first loop is completed, so I wanted to get a quick few pics of it before I start putting down the cork roadbed and track for the first loop.  I will say this:  when the helix is finished I will use the inside as a tornado shelter!  As flimsy as the rods may look, the wood pieces are solidly in place!

Layout Progress Report #9 as of 03/14/2010

The fun has begun....the helix, that is.  As previously shown, my layout is 2 levels, the upper scenicked level connected to the lower staging level with a single track helix.  The design specifications for the helix are as follows:

• Single track 
• 17 inch radius
• 2.5" rise per loop
• 6.5 loop total

Using nominal 1/2" plywood with cork and Peco 55 track this yields a height clearance of almost 1-7/8", with a grade of 2.34%.  This is more than the NMRA recommended clearance of 1.65"

If you do a search on the internet you will find many different techniques for building one, including purchasing some kits to make the helix build simple.  I decided to make the components and build it myself, as it is the most cost effective solution.  Keeping with the cost effective theme meant that cutting the helix loops as semi-circles out of plywood would also not work as it leaves a lot of wasted wood.  I decided to use a technique of making a circle out of 12 straight pieces of wood, with each end of the wood cut at a 15 degree angle.  Here is a CADRail drawing of what it will look like:

With a table saw and miter saw it will be rather straight forward to cut these pieces to size.  I will be able to cut all the wood needed for the helix using one piece of 4x8 plywood.  To join the pieces of wood to make the helix I will cut an 1/8" slot into the edge of the wood and connect them with some 1/8" thick masonite pieces.  The same masonite pieces will be used as supports using threaded rod risers.

I started working on it Saturday morning after a trip to Lowes for the remaining hardware.  First thing was to rip the plywood to 3" wide strips, and then cut them down to the appropriate length with the miter saw.  Here you see the pile of wood strips cut to length:

Here you can better see how the wood pieces will work together:

Now is time to cut slots into the ends of the wood strips.  To  do this I am using my router table and a slot-cutting bit.

Here you can see the business end of the slot-cutting bit with a guide bearing on top.  It will make short work of cutting the slots.

After some serious sawdust the wood strips are slotted.

Then I cut the 1/8" masonite slot pieces with the table saw and miter saw, and drilled some holes for the threaded rods.   Here is the whole pile of parts that will make the helix.

First I made a jig to mark the track centerline on each piece out of a couple pieces of wood.  Doing this before assembly will make things easier.  Once again I will use a punch to mark the line.

Next it is time to grab one circle of pieces and lay it out on the base to see how it will fit.  I also marked where to drill the holes for the threaded rod risers.

The next close-up will give you a better idea of how the helix will be put together.

Once everything is laid out and marked, it was time to remove some of the base where the helix will start.  I calculated that after 3 sections the helix will rise above the base, so I cut a hole with a jigsaw for that.  I also drilled the holes for the threaded rod risers and started putting them into place.

All the threaded rods are in place, secured in place with nuts, washers and loctite threadlocker.

Here you see the first three pieces in place.  The first piece is spliced to the base, with the remaining pieces supported by risers under the base until the first masonite tongue piece is used.

So the helix construction has begun, next time I will continue to chronicle the building of the helix....