While I’m spending a lot of time playing with decoders, that’s not the only thing on my mind. One idea that’s been eating at me for a while now is to redesign the under-table storage tracks. I’d originally planned to locate these under the Urban Station scene, reached by a helix that led down to them from the “unsceniced” end.

On reflection, this was less than ideal. First, any access to the underside of the layout for wiring work would require removing all of the trains from storage. Second, the helix to reach them would be quite long, at five and a half turns, which would be expensive and overly complex. Third, if I needed to work on the trains, I’d be kneeling on the concrete floor and reaching into a narrow space to access the trains on the back track, which pretty much guaranteed I wouldn’t be able to do much. The only thing it had going for it was that I could store a full-length sixteen-car Shinkansen (2.5m or eight and a half feet long) down there.

I’ve also been toying with the idea of putting a “cap” above the helix, and adding scenery to the “unsceniced” end, perhaps a small hillside with houses and narrow roads, topped by a forested area with a Shinto Shrine or Buddhist Temple (or both). And before I built that, I really needed to figure out what the helix was going to look like, and how I’d support the cap above it without interfering with the trains.

This past summer I’d been cleaning out the basement, and had freed up an area off to the side of the layout. Not a large area, but it would support a table about 80” (2.0m) in length and a bit over 20” (51 cm) wide. This gave me the idea of building a small visible “yard” scene, that could double as a small storage facility. It would also be reachable by a much smaller helix of about 3 and a quarter turns.

A bit of measuring has me largely convinced that I can build the helix fairly simply using Tomix double-track 428/465mm viaduct track. I’ll need to deal with the difference in track spacing at each end (Tomix is 37mm, Kato is 33mm for standard Unitrack), but there is room at both ends to build a transition.

Of course, all this is pointless if there isn’t enough room to store anything. So I knocked up a quick diagram to see what I could fit.



That’s not too bad. No room for Shinkansen, but I can store four 10-car commuter trains without using the two center tracks (which allow trains to switch from the inbound track to the outbound track). Two of those tracks are even long enough for my 11-car Yamanote commuter trains. That means I can rotate through a set of six commuter trains (four in the yard, two on the main) without taking anything off the track. That’s pretty good.

Beyond that, I get at least two and possibly three tracks that can hold specialty trains that are short (e.g., Joyful trains or my East-i E track inspection train). The last couple of tracks can store freight cars and locomotives.

And if I really want to store a long train, such as my 16-car M250 express freight train, I can always split it across two tracks. The table height (a bit below waist level) makes working on trains on the table fairly reasonable.

And finally, I have room in one corner for a couple of buildings, a turntable, and an enginehouse or engine/car repair building, so I can make a small scene and not have this just be a ladder of storage tracks (this also gives me what can be half of a longer yard with some support facilities if I eventually get a larger basement.

So, there’s enough here to justify the helix. Now, what does it look like? Well, in the space available and with the clearances I want, I can’t quite manage the 2% grade I wanted, but I’m under 3% and that should be good enough for Kato trains (which supposedly will climb 4% grades as a general rule, although I’m not sure that extends to 11-car commuter trains).

And it looks like my idea of using the Tomix viaduct will work. I have some issues I need to work out with supports. Right now I’m planing 1/4” threaded rod on each side of the viaduct at eight locations (where the joints between 45-degree viaduct segments are) with nut/washers supporting short strips of thin brass or aluminum to hold up the viaduct. I think I have space to mount the rods, but I need to do some mocking up to be sure. If not, I’ll step down to the next size of viaduct, but that will increase the grade and/or decrease the per-loop spacing (and thus clearance).

I did discover one mistake: when I added some end-sections to the two major scenes (green parts on the diagram at the top) I left inadequate clearance on the one at the end of the Urban Station scene, so I’m going to need to cut it back a few inches. Fortunately it’s removable and holds nothing except some painted foam today, so trimming it won’t be a big issue.

And that’s where I’m at right now: I need to do a bit more work before I’m ready to build the cap and scenic it. And the cap probably will come before the helix and the yard scene. But I’ve got a plan, and even if I end up changing it later, that’s something to start with.

Monthly Status for January 2013

This month went to decoder work. Mostly prep, but I’ve done my first round of tests and am in the middle of preparations for doing some more. In the process I’m learning a few things about decoders I’d overlooked before (like how they map function keys to outputs; somehow I’d never needed to know that before). I’ll have a lot more to say on this in future posts. At the rate I’m going, I expect to be engaged in this activity until spring comes, if not longer.

Tags: Administrivia, Benchwork, Tomix, Helix