Lennart's Model Railroad Blog

Lennart's Model Railroad Blog

About this blog

This blog is about my current model railroad layout project; The N scale "Summit" layout, which is a freelanced interpretation of the Southern Pacific Tehachapi tunnels and their surroundings. Or at least, that is what it is meant to be. What it will turn out to be is another matter. The banner photo above shows what I want to recreate in N scale.

Turnouts, part 7

Track layingPosted by lennart Sun, January 18, 2009 16:50:14

I have now finalized the first turnout, and it works. Well, at least on the workbench. How it will operate on the layout with real trains and not just a loose truck remains to be seen. But so far it looks promising. Here is a description of the last steps.

I started by installing the closure rails. That was straightforward. I glued tie plates to the ties, cut the rails to length and glued them to the tie plates. I did only glue the rail on the 10 tie plates closest to the frog, to make the point ends movable. I also left a gap between the closure rails and the wing rails, for electrical isolation of the frog area.

I then turned my attention to the throwbars. The stuff I bought from the Proto87 Store constisted of plastic throwbars, to be mounted between the head ties, and metal bars to be inserted in holes in the plastic bars. There shall be two such bars on each throwbar - one for each point. The "pointy" part of the bar shall rest on the rail base and press the rail towards the stock rail when the switch is thrown.

It immediatelly became obvious that these things were too large for code 40 rail. The plastic bars were too wide and the metal bars too high. The wheel flanges would catch them. So some kind of modification was required. I started by making the plastic throwbar more narrow, so that it would actually fit between the head ties. I then filed the metal bars to make them considerably lower. The "pointy" part would disappear in the process, but I figured it would be enough if the bar pressed on the point rail base. The photo below shows an origianl throwbar with an original metal bar to the right and my modified version on the left.

The next picture shows the final throwbar when installed.

One problem remained. When the switch is thrown then one point shall be pressed against its stock rail, but the other point need also to move towards the track center line. I could either bend the point rails inwards, and trust them to move by there own tension. That seemed not totally reliable so I decided to take of advantage of the fact that prototype tornouts usually have two throwbars.

So I set out to make a second one out of a piece of PC board tie. The only purpose of this bar would to drag the other point along when the switch was thrown. Two ties away from the actual point there would be enough material left of the undercut rail base to allow the point rail to be soldered to PC board bar. The photo below shows the point area with the PC board bar. The copper foil has been removed in the middle, to avoid an electrical short between the point rails.

So the actuating rod from the switch machine will move the plastic throwbar between the head ties. The metal bar will then press the point against the stock rail. The PC board bar will move as the point moves and drag the other point away from opposing stock rail.

And here the switch has been thrown to select the diverging route.

Before I eventually move the turnout to the layout, and attach an under-the-roadbed Tortoise switch machine, I will dress it up with some joint bars at the frog area and and add some cosmetic throwbar linkage. And of course the rail shall be wheathered.

Conslusions from this project: To build an N scale code 40 turnout with only wood ties, with tie plates and a more prototypical point area is doable, but is not realistic for a larger (or even medium) layout. For my small layout, where there will be no more than 5 turnouts it is managable.

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