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.

U25B Decoder Installation

Rolling stockPosted by lennart Sun, June 27, 2010 20:14:48

I have some engines sitting in line waiting for decoders to be installed. Two of those engines are Atlas U25B:s. The other day I installed a TCS M4 decoder in one of those (SP 6700). A straigtforward installation where I reused the forward LED from the existing ligth board, but sacrificed the rear LED in order to get the decoder in. Here is a picture of 6700 heading out of the staging yard:

I think I mentioned in an earlier post that I had some problems with one of the staging yard turnouts. Some cars had a tendancy to derail when passing that turnout. I thought I had fixed that problem, but when test running SP 6700 and its new decoder the loco derailed on that precise turnout. Every time. But only when taking the straight route! When doing so it always climbed the point rail and the front truck took the divering route instead. I am not 100% sure but I think the problem was related to the spacing between the point rails. They seem to sit to far apart on this particular turnout. Anyway, I managed to make the problem go away by installing a pair of guard rails, as shown below:

I cut them from a piece of code 55 flex track, and glued them in place with CA.

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