One note about this construction is that I've made some improvements in the track installation techique. I learned, during the prepping of the Atlas switches, to file down rough edges in the switch rails that can catch wheels and cause derailments. Having done that procedure now for 24 switches I automatically paid more attention to the rail joints in this new section of construction, using the diamond files and even the rotary tool to make all rail connections super smooth. During testing I found that the newly installed track resulted in very smooth operations -- even better than what I found on the previously installed track. At some point I'll go back and apply those lessons to the rest of the staging track.
The only other construction note is that I compromised a bit on the wiring standards. The most recent construction consisted entirely of track re-used from the first staging attempt, usually in groups of 2 or 3 track sections soldered together and with the original feeder wires intact. As a result, I ended up with a few single sections of track with no feeder wire. Instead of adding an extra pair of feeders I just soldered these to one of the adjacent track sections. Throughout this process I've been using the multi-meter to test for shorts and I've found that there is virtually no resistance between adjacent rails soldered together, so I expect no troubles with this compromise. In fact, I'm beginning to think that my feeder-to-every-other-rail-joiner stategy may be overkill.
Once everything was completed, cleaned, and tested with the DC SD90MAC locomotive I hooked up the Digitrax and tested a long train on both grades. Here's a picture from part of that test:
The train in question is 33 Athearn Bethgon Coalporters, which are harder to pull than most other cars due both to weight and higher resistance wheels. With the two locomotives this train is almost 13' long -- over 2000' scale feet -- and would justify two or three lead engines in normal operation.
I found that two Kato diesels (SD40-2, latest release) pulled this up the 0.9% approach grade (the upper tier staging entry track near the wall) without any noticable affect on speed. Just for grins I tested the same train up the short 3.5% grade in the upper tier staging yard (as shown in the photo) and they got up just fine, albeit with some speed degradation.
Alas, when I tried two Atlas diesels (SD60M) they struggled mightily with just the 0.9% grade, making slow progress at full throttle and lots of wheel spinning.
This matches my previous experience with Kato and Atlas diesels from my 2002 test layout, although at the time I attributed the difference to the fact that the Atlas diesels I had then being only 4 axle (dash-8s) versus the 6 axle Katos (C44-9W). But, the Atlas SD60M also has that problem and it has 6 axles. Fortunately, most of my mainline modern freight diesels are Kato (17) versus only 4 for Atlas. For now I'll stick with Kato until I do some research and see if the Atlas problem can be solved easily. If not I can get by with assigning the Atlas engines to lighter duty work.
Finally, a note about time -- mostly because when I re-read these posts later I'll wonder why it took 3 weeks to finish the last section of the upper tier. My last post on upper tier construction was on March 28. One factor is that there was a lot of work required in this small space. 8 switches, reusing already soldered track, and fitting a lot of track into a conjested space all required extra time and attention. But the main factor is that I didn't have a lot of time the past 3 weeks due to lots of work at work and at home (prepping for 2 birthdays, Easter, some financial matters including the IRS, and several snowstorms that required driveway attention).
I may get more free time in coming weeks, but as the (hopefully) last Spring snow melts the outdoors is beckoning -- first the spring thinning of our little patch of forest, then the outdoor railway, which will generate a few posts of its own. I resolve to keep making weekly progress on the N scale layout, however. The next step is the middle tier of staging.
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