Friday, July 6, 2012

Diamond, part 1

All the tie strips for the code 55 rail are glued in place, and the complete trackage is now easily distinguished. As seen in this picture.

Sometime ago I decided to make two of the spurs cross, creating a diamond (which can also be seen in the picture). This to create some visual interest. And for the opportunity to build a diamond, which I have never done before.

When now installing the tie strips I was forced to consider the diamond as well. I started by drawing lines where the rails would eventually cross. I also marked the position of the ties.

After having studied some pictures of diamonds on the Internet I realized that the ties needed to be diagonal to both sets of rails. Otherwise they would not be able to support rails in both directions at the same time. I arrived at the pattern in picture below.

I had some H0 6" x 6" scale lumber at hand, so I used that to cut the ties for the diamond. In the end I squeezed in yet one tie on each side. This to get a tighter tie spacing. The spacing I had originally planned (as in the picture above) just did not look right.

Then I could proceed with the adjoining ordinary ties, like this.

Next I will start laying track, but I will save the diamond for last. But I have understood that I will need an auto reverser or a DPDT switch to handle the frog polarity of the diamond. Since I want the diamond to adapt automatically I have ordered a Digitrax AR1 to have handy once track laying reaches the diamond.

Thursday, July 5, 2012

Rail height transition

With the switch machines in place I could turn back to track laying. I have so far only laid the code 70 track. The code 55 spurs remain to be done. But before I could begin that task I needed to fix the rail height transition. Since I do not use any rail joiners this was a simple matter of shimming the code 55 track so that the rail tops became aligned with those of the code 70 track.

I used the standard procedure applied when building super elevated curves - pieces of masking tape cut successively shorter and used to build up a smooth grade. In my case it turned out that four layers of tape was what it took. Here is a picture of some masking tape shims arranged in front of the existing code 70 track.

A this test fit of some tie strip with a piece of code 55 rail on top shows that the rail tops are aligned.

Wednesday, July 4, 2012

Reinforced actuator wires

Due to a number of reasons, a wedding anniversary trip to Rome and a cold among others, have made layout time scarce lately. But the last few days I have managed to make some useful progress - all the Tortoise switch machines are now hooked up and possible to control with toggle switches on the fascia.

Most of them worked fine on the first try, but a few of them did not. They did not move the points all the way up to the stock rails, with a derail as an inevitable consequence. The first attempt to remedy this was of course to slide the green plastic piece on the Tortoise, the one with a hole which the actuator wire runs through, further down. This to create more actuator wire swing. But that did not help.

Since there is quite a vertical distance between the top of the Tortoise and the turnout, 2" of foam and 1/3" of MDF, the stiffness of the actuator wire could be the problem. The original wire is quite flimsy, so I had switched to another type of wire from the start. I used wires about 1 millimeter (around .035") thick. So I ruled out the wire as the cause of the problem. Especially since 7 out of 9 turnouts behaved as they should.

The only reasonable reason for two of the turnouts to have problems is then that the points of those turnouts are harder to move all the way up to the stock rails, as compared to the others. And the only reason for that is the electrical wiring of the point rails. My guess is that the wires I use for this simply create to much mechanical resistance.

Since I could not, at this point, make anything to lessen that resistance, without losing power to the points, my only option was to overcome the resistance (brute force). And since I refused to believe that the problem was lack of force in the Tortoise itself, it all came back to the actuator wire. It needed to be stiffer still, for these two turnouts.

The only thicker piano wire I had at hand was more of a thin steel rod than a wire, so I did not want to use that. Some flexing of the actuator would still be healthy, both for the turnout and the Tortoise. So I ended up soldering a piece of stiff rod along part of the actuator wire, making the wire stiffer but still flexible. The photo below shows a wire with a rod attached to make it stiffer.

The wire reinforcement turned out to be the trick. Both troublesome turnouts now move the points all the way up to the corresponding stock rail!

I since detected yet another turnout that sometimes shows the same effect, but now I know how to fix it.