Monthly Archives: March 2014

Lighting & Benchwork Update

Those of you who have been following along know that one of the core electronic pieces I’ve been working on for the CRNW is an LED lighting system tied into the fast clocks. Over the run of an operating session, I want to transition from “dark” (really dim blue light) through the brilliant warm light of daybreak, the bright white of midday, and the through the golden hour and sunset back to dark. The system will consist of the fast clocks – obviously – as well as a MRB-GIO to figure out color and intensity, and then a set of power booster boards that actually control the 2000W going to the LED strips. The power boosters will be local, each controlling <20ft of layout, to keep the amount of power being switched to a more manageable level.

The prototype power booster boards for the LED lights showed up a couple weeks back, but this weekend was really the first chance I’ve had to try integrating them with the full system. I connected one up to my test LED strip and mounted it back over Cordova, and then connected it to a MRB-GIO and did some basic programming to turn it into a lightning controller.

Results are promising – I need to do a bunch more tweaking on the exact light transitions, but my first try came off pretty well. I also did a few tests using a bunch more strips to increase load. The system was designed for up to 6A per channel, so I cranked it up to around that. Heating was actually less than I expected – the board only slightly warm to the touch even switching 6A on a couple channels.

I’ve posted a few photos of the new power control board, as well as some samples of midday, evening, and night light. Night isn’t that bright, I promise. It’s just the camera evened out the exposure.

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On the benchwork front, I did get the top deck extended from Strelna over to the north end of the Chitina yard. The bottom deck is still being pondered – I’d really like to add a short Katalla Branch as a very low level. The problem is that I can’t figure a way to shove a helix under where the junction should be. I’m contemplating a train elevator along the wall (hidden behind the Miles Glacier Bridge area), since trains to/from the coal fields above Katalla would be short – 6-8 cars plus power. Regardless, I’m still pondering it.

Oh well, off to Memphis for the week tomorrow. I’ll figure out what I’m doing about a potential Katalla branch train elevator when I get back.

Benchwork Update

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Just a quick note to say that progress is finally being made again.

Last Thursday, I ripped two more sheets of 3/4″ plywood to replenish my dwindling supply of plywood dimensional lumber. It’s really remarkable how quickly building benchwork grid goes through a supply of the stuff.

This weekend, I’ve spent significant type tackling building the benchwork itself. The result is that the grid is now complete from Kennecott through Strelna on the upper deck, and Cordova through mid-Alaganik (where it turns the corner) on the lower deck.

One of the things of note is the large gap for the Kuskulana River bridge. My layout includes four of the railroad’s most notable big bridges – Miles Glacier, Chitina (third crossing of the Copper), Kuskulana, and Gilahina. Three of the four are selectively compressed, but the Kuskulana crossing will be done to scale. That means 238 scale feet of depth from railhead to water, or about 18 inches. Fortunately, the deep vertical part of the canyon is only about 170′ across at the water line, and about 190-200′ at the rim. The larger bowl sort of depression of the valley is about about 775′ across, or just under 5 real feet in N scale. The CRNW spanned the gap using 2x 150′ deck trusses (one on each side) and a 225′ deck truss over the main canyon. Then there was another 250′ of trestlework to connect the steel bridges with the grade.

Here’s a couple pictures from when I visited back in 2009 that illustrate the main chasm and the bowl-shaped valley it cuts through:

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And finally, here’s the piece of benchwork that will eventually support the model canyon – yes, it seriously impinges upon the bottom deck, but it’s the only place I do this, and it’s to make a significant visual element that everyone familiar with the line will recognize.

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