The New SLF

In 1996, we moved into a new house, but one that totally lacks any modeling space beyond the garage. To make matters worse, the garage is without a suitably configured corner in which to mount the existing layout.

As most model railroaders know, one excuse for a rebuild is as good as any. The space issues combined with technological advances in the hobby (namely Peco Code 55 track components), limitations of the bookshelf design, and my desire to have a "better" layout resulted in the decision to start over. To spur myself on, after the 2001 Albuquerque GATS show I dismantled the old sectional layout and got rid of the framework. Though there's still a lot of garage cleaning and rearranging to do, I'm currently planning and building the 21st century version of the SLF to fit in a 107 by 406cm (42x160-inch) area along one wall of the garage.

Level "0" - Swiss Staging

Plan of the lower hidden level - Each grid square is 76mm square (3"x3")
Click on the plan for a larger view

The lowest level consists of staging that feeds the double-track mainline leading north to the Simplon Tunnel. This construct solves two problems of the earlier layout:

  1. I have a lot of Swiss prototype equipment that must be segregated from the Italian part of the layout (because of the prototype's differing catenary and electrical systems)
  2. Though I'm sold on operations, there are times when I (and visitors) just want to watch a parade of trains

On the 'map' this layover yard represents the city of Domodossola, the Italian station where the SBB turns over international trains to the Italian Railways. To provide adequate space for the many trains that will transit this heavily-used corridor, the layover yard includes eight through tracks and three stub-end tracks. The stub tracks will hold push-pull sets like the RAe TEE and the Bern-Lötschberg-Simplon automobile shuttle train (if I can get it to operate reliably in push mode).

A full 165mm (6.5") of elevation separates the hidden trackage from the first visible level. In a layout of limited size, a helix is the obvious solution, but having previously built one following the traditional flex-track-on-plywood-circle method, I was not looking forward to the task. Just in the knick of time, a photo in the NMRA Layout Design Special Interest Group's Layout Design Journal led me to the idea of using Kato's new double-track viaduct to construct the helix.

The 381mm & 414 mm (15" & 16-5/16") radii of the double track are a perfect fit to the depth of the layout design! Each loop of the "trial" helix raised the track by 63.5mm (2.5") resulting in a 2.65% (1 in 38) grade on the inside track and a 2.45% (1 in 41) grade on the outer track. The Swiss railway (as well as the Italian) employs left-hand running - spiraling up in a clockwise direction allows the gentler grade of the helix to be on the uphill side. By November 2001 it was obvious that the +2.5% grade on a curve was too much for some of the typical consists I had planned. In order to reduce the grade to a manageable 2%, I modified the Helix to an oval design by adding Kato's 248mm (9-3/4") straight double-track viaduct sections to the loops. Due to the lack of transition curves, this does cause a bit of a "jerk-and-jog" in the trains, but I think it will be okay.

The new Oval Helix (original circular helix shown in the inset photo)

The secret to supporting the helix is the pier structure, built of square brass tube and square Plastruct ABS plastic. The core of each pier is a continuous piece of 1/8" square brass tube affixed to the base board. Progressively longer spacers are cut from the Plastruct and strung on to the brass tube to form the initial grade. The individual pieces of viaduct are snapped together and strung on the piers (at each joint Kato fortuitously provided a pair of square holes that allow the brass tube to pass through). Once the first circle of the helix is complete, the rest of the needed Plastruct spacers are cut to the same length, thereby maintaining the grade and the computed minimum separation of the decks.

Initially, I planned to use Kato track just for the Helix. As that decision percolated, I gradually 'warmed-up' to the idea of continuing the Kato track through the entire hidden portion of the layout. Normally, the idea of 'snap track' brings out the garlic and crucifix in me, but there were some obvious and darned near irrefutable advantages to consider:

  1. Kato's turnouts with their self-contained switch motor are ideal for the hidden yard - zero maintenance, and if there is ever a problem, removing and replacing will be relatively simple.
  2. The turnout's power routed live frog is on my list of track "must haves."
  3. With a few gaps, the track is compatible with my plan to operate the layout using Digital Command Control.

Planning for DCC is not the "cake walk" I imagined it would be! Since all this area will be covered (but adequately accessible for retrieving derailed trains and performing light maintenance), I've had to provide for all of the needed electrical hookup during construction. Because I hope to someday dispatch trains on the Simplon main via computer, I need to include switch machine control and to plan for detection and transponding of the trains. This latter need has upped the complexity of the gaps and feeders to excede that required for a conventional DC layout!

There was no argument that Unitrack would be expensive! But careful shopping helped me save 20-25% on each item (Hint: get some on-line prices and take them to your local hobby shop; most owners will jump at the chance to meet the price on a guaranteed bulk order!)

Oct 2003 - 100% Unitrak not necessarily a good thing! It occurred to me that I had unwittingly engineered additional electrical complexity into the design by using Kato turnouts at the departure end of the hidden yard. This would also increase the cost of the DCC installation due to additional stationary decoders and because the Kato turnouts need a special adapter to work with the Digitrax stationary decoder. What I needed was a simple 'spring' switch ladder at the departure end. A quick comparison showed that Atlas #6 Custom Line turnouts were geometrically similar to the Kato units. The change has been made in both hidden yards and the excess Unitrack turnouts sold on ebay.

26 Jan 2004 - Getting trains on and off the layout will only become more difficult after catenary is installed! This may not be a big problem once the control system is in place, but now is the time to think about it. One idea is to extend one of the stub staging tracks through the end wall of the layout, crossing the loop at grade. I can then attach a 'fiddle track' to the layout to add or remove trains. A simple DPDT interlock will protect the loop.

Front access to the hidden yards is covered by a pair of scenicked lift-off facias that add 15cm (6") to the front of the layout. The primary scenic element of the lift-offs are the roadway that traverses the Simplon Pass. I've animated this road using Faller's new N Scale Car System.

Now in N Scale - the Faller Car System (catalog #162000)!

Up to the next level!

Last update: 22 November 2007