Wednesday, 30 July 2014

Sandwich Baseboard:

My current layout under construction is primarily an around the walls structure with one island section. The frame is suspended from the walls with no legs. This facilitates clear access underneath for wiring and also keeps the floor clearer. Previously I have used aluminium square tube as a frame and styrofoam as a baseboard. This worked very well but had one limitation which we will discuss later. My current frame is a traditional open grid box frame of 75-100mm x12mm structural plywood. Keeping everything lightweight was important.

On a previous layout and also on a diorama I built, whilst the current house was being completed, I used a sandwich design of styrofoam between boards as the base. This method uses timber on either side of 15mm styrofoam paneling. My first effort was based on 3mm MDF timber as the "bread" around the 15mm stryrofoam sandwich filler. This worked well. I did seal the MDF with paint before installing in case water penetrated the glue of the sandwich.
On my current layout I decided to be more conservative and use 3.5mm plywood, as the bread. Luan plywood or MDF would save money and probably work as well. I started with 2400 x 1200 x 3.5mm plywood, and glued 15mm styrofoam sheets between the plywood sheets. I experimented with several glues. You can buy special glue for styrofoam but in the end I found full strength water soluble PVA white glue very effective. First lay out the first sheet of plywood on a flat surface and coat the whole area with glue. Spread it with a brush. Use water if necessary (sparingly so as not to dilute the glue too much)  to help the glue spread. Next step is to lay the foam sheet on top of the plywood. Then spread glue over the styrofoam sheet and lay the top sheet of plywood on top or alternatively spread glue on the second plywood sheet. Use weights to compress the sandwich over 24 hours whilst the glue dries.
The sheets of sandwich material once made could then be cut into the various sections, just like cutting regular plywood.  For straight cuts use a circular saw. For shaped cuts use a jig saw with a fine blade. Before installing any sections and after the sections were cut I sanded and then sealed the edges with "No More Gaps".  After the No More Gaps dried I painted the whole sandwich section to help seal it. Painting the sandwich an earth colour would be beneficial for future scenery applications.
The sandwich section is slightly lighter than say a 12mm plywood section and just as stable - perhaps more so. The only downside is the sandwich is 21-22mm thick versus a 12 mm plywood base. However if there is a problem such as for sections where track passes underneath and you need maximum clearance you can cut the lower elements of the sandwich and create only a 3.5mm overhead height if required.
I have had this design in use for nearly 10 years and many colleagues also have used it successfully.
There are some advantages over dense styrofoam and plain plywood.
With the sandwich of plywood on both sides and styrofoam in the middle we have timber top and bottom which you can easily screw into. This is handy for mounting small items under the layout like wire hangers and switches.  The weight of the sandwich overall is lighter than plywood. Sytrofoam is good but when you want to attach something to it having a plywood base helps. Of course all methods have positives and negatives, but the sandwich model works well for me.
Here is a section laid on some risers. This section is not sealed on the edges with No More Gaps, and is also not painted so you can easily see the construction. The sandwich will accept a wallboard / chipboard screw to attach it to the riser and keep it stable.

Here is another view of the sections in place showing the risers and supports.
Here is a long section of sandwich board installed. 
Here is another picture of the supports for the sandwich base. Having the sandwich made of plywood allows it to be screwed to the risers. The sandwich base here joins traditional plywood with a section underneath allowing the two sections to be screwed and glued together.
Here is a typical set of risers and supports. The sandwich board above is screwed to the riser horizontal support. 
Give sandwich boards a try. I have sandwich boards, plywood, and spline roadbed on my current layout which you can follow on:

Thursday, 17 July 2014

The First Track:

Once the frame was installed it was time to make the track base for the lowest section of the layout. This was the staging area and reversing track. As mentioned earlier my professional consultants convinced me to have staging and in consultation we agreed a good idea would be to have this "hidden" at the front of the layout where it was most accessible. Staging is an area to store trains once they reach a destination, or to hold them until a next use on the layout. When you are operating hidden staging can be an area where visitors believe the train is actually out of site but in another area. A lot of this reversing section is hidden and travels along a back section of the frame. Hence this section was installed first. I also wanted to make sure it was as good an area and reliable as possible before proceeding as this area would be the most difficult to work on once the final layout was in place. 
The staging section travels from a mid level to the lowest level at the back of the layout before joining the layout at the front for a very long 4 track staging area. On returning to the mid level the train is reversed. All the track is accessible by using my low mobile chair to slide under the layout.
At this stage of construction I made my first risers. Risers are 50mm wide plywood with a section (50mm x 20mm) on the top of the riser that gives a larger base to support the track base. Prior to installing I make the riser and drill a 2mm hole though the additional section attached to the riser so that later I can screw the track base to the riser from underneath.
Here is the first section with risers.
The base for the staging area is all 12mm top grade plywood, either 50mm wide for single track, 80mm wide for double, or 120mm wide for the 4 track section. Once installed we then focused on the roadbed. My choice is cork which when purchased from bulk suppliers is very cheap. A 100mm x 60mm sheet of 3mm cork is A$5.50. It is easy to cut into strips to suit the track width. On the 4 track section I made the section 110mm wide. For the corners and curved track we split the single sections so they bent around the minimum radius of 18 inches. The cork was attached with white glue (PVA) spread to cover the area of the cork roadbed and then pinned down with punch pins. The PVA glue was spread with a cheap paint brush. Here is a section just glued and pinned down to dry.

The next phase after the cork dried was to sand the cork to ensure a smooth base for the track. 
I needed to get the staging track installed and working first before adding the next and major level of the layout. So this meant installing the power and control elements of the layout. I moved to Digital Control (DCC) in 1997 with a System One unit. This has evolved into an NCE system. I plan to use just one power unit with 4 isolated sections each with each own section controller. The staging area will be one section and run off the second control of the NCE power controller which enables automatic reversing of the section. DCC buffs will understand, but I apologise to non model railroad technical readers. On connecting up my DCC Controls I had a short circuit. I approached Gary Spencer - Salt from Model railroad Craftsman ( the local NCE and SystemOne supplier) and he sold me an EPROM upgrade. Unfortunately this did not work and after several iterations his repair person said my Command Station was dead. Gee, 17 years of service and dead!!.  Gary advised he had possibly one last SystemOne Command Station board and he gave it to me. It worked. Thank you Gary and Model Railroad Craftsman at Blacktown in Sydney.
One lesson I learnt many years ago was to wire every section of track and not rely on rail joiners for power. I also prefer to wire the track underneath before installing it. Here is an example of a section of track wired prior to installing. As we install the track we identify where the connecting power leads are and drill holes through the cork and baseboard for those wires to attach to the bus power leads below.

One area to also address is the power bus leads and wire selection. I use household power cable and shred the outside white plastic to expose three 15amp+ cables in black, red and green. The red and black are the power bus cables. I use the green and some separately purchased 15amp white to be my main staging area bus wires.
Then it was time to lay the tracks. My approach is to use coloured caulk to hold down the track. 
So now we have the track roughly in place and the feeder wires through the holes to connect to the bus bars below. I spread the caulk and spread it so that it does not rise up above the sleepers of the track. See the photos below.

Laying the track on the caulk and using the wire leads through holes to the bus bars below will roughly align the track. Then I use a meter long metal rule to ensure it is straight. It is key to get the track straight or as good as you can using eye sight and then a roller to impress the track into the caulk.
Where I have already laid track I use a guide built from 40mm plastic to get he tracks parallel. See the photos below.

I would like to say every bit of track went down perfectly. But it didn't. I discovered bad solder joints, and some of the track that I had recycled from a previous layout proved hard to use. Also I had some different brands and this was difficult to get level and perfectly connected.
My advice would be not to cut corners by trying to save a few dollars on old track. Code 80 track is a different height to code 55. The sleepers are different height. I cut out the bad sections of track and installed new track and now am reasonably satisfied with the staging tracks and the first tracks laid. 
All the new track laid will be the latest Peco concrete or wood sleeper code 55.
Here is the first train being tested on the staging tracks. I will run long trains and back them up over all tracks prior to being satisfied and progressing to the next level - the key layout tracks. But here we are in Mid July 2014 after 3 months work.

Initial Wiring:

I needed to get the staging area track laid first. I also realised that I needed to get the bus wires in. The next step was to wire up the section controls and the DCC controllers so we could test the first trains and wiring.
I purchased 100M of household power wiring and stripped the insulation so the three insulated wires were exposed. One red, one black and one green wire. The red and black would be the major bus wires separately labeled to identify their circuit. The wires are 2.5mm copper and rated at 15amp.
For the staging area which also was a reversing loop my bus wires would be a green and white wire.
A number of other decisions were made at this stage:

1. Wiring switches:

All the switches would have the frog isolated by cutting through the rails just before the frog, and soldering jumper wires across the outer rails to provide continuous power. Previously I have cut the rail with a Dremel saw but on too many occasions I slipped and hit the out rails. So this time I ordered a jeweller's saw from Micro Mart to do small fine cuts. The cuts were sealed with .010mm plastic super glued into position.
The frogs are all powered with "Frog Juicers" from Tam Valley, in California. Below is the frog isolated section with plastic super glued into the gap. The second photo is a green wire soldered to the frog of the switch. This lead goes to the Tam Valley "Frog Juicer" which switches the polarity and provides continuous power to the isolated frog of the switch.

2. Switch Control:

All the switches will initially be controlled manually. The Peco switches have throw bars with "blobs" on each end which is ideal to push with the fingers, or as one member of the local NMRA does move with the top of a clutch pencil. The clutch pencils have an indentation in the end exactly the right size to fit over the Peco "blobs". I will probably get around to making some combined uncoupling picks and switch activators from plastic or wood in the future.

3. Wiring Track:

All track is wired prior to installing. I cut the dividers between the sleepers underneath and file and tin the rail prior to adding the jumpers.

A couple of tools are handy to strip the insulation from the cable and to bare the bus wires to connect. Here are some pictures of the tools and stripping wire.

4. DCC Block Protection:

The layout will be divided into 4 separate electrical circuits protected by circuit protectors.
Here are the 4 circuit boards - one has three circuits and the other is a single.
The staging tracks are connected to the single control.

All good - connected up to the Command controller and voila - the train ran on the staging tracks. Here is the first train on tracks.