This page is one in a series on the buildout of an N scale model railroad depicting the BNSF Scenic Subdivision in Washington state in the Cascade Mountain Range. You can find the main table of contents for all the articles in the series HERE.

Welcome to Model 160 and we hope you enjoy the project!


So our first mountain scenery layout project will feature BNSF’s beautiful Scenic Subdivision or Scenic Sub for short. Originally built by the Great Northern Railway as means to cross the Cascade Mountain Range, the Scenic Sub covers roughly 155 miles from Seattle, Washington to Wenatchee, Washington. It includes steep ascents/descents of 2.2% grades for long stretches which tax any equipment (especially at elevation) clawing its way to the summit.
The area we are modeling and talking about can be seen here on Google Earth with the Cascade Tunnel on the right and Seattle on the left:
Here is one of Great Northern Railway’s PR shots:
The part we are modeling is from roughly Gaynor Trestle through Gaynor Tunnel climbing ultimately to the eastern portal of the the longest tunnel in the United States – The 7.8 mile long cascade tunnel:
The best way to show part of the reason why I choose this area is to show you this:
BNSF heading west across Gaynor Trestle over Nason Creek (Joel Hawthorn Photo):
Amtrak Empire Builder headed east over Gaynor Trestle (Matt Donnelly Photo)
BNSF intermodal headed east about to enter western portal of Gaynor Tunnel (Joel Hawthorn Photo):
Amtrak Empire Builder heading west across Gaynor Trestle (Joel Hawthorn Photo):
Eastbound out of the eastern portal of the Cascade Tunnel (Reed Skyllingstad Photo)
As you can see, a beautiful area for railfanning…
The current Cascade Tunnel is actually the second Cascade Tunnel. The original tunnel was located at 500 feet higher elevation and required a number of switchbacks through difficult terrain and avalanche areas prone to deep snow. Relocating the tunnel also removed 21 miles of 2.2% grades. So a new tunnel was built and opened in January of 1929. It was originally electrified territory until diesels started ruling the grades and a ventilation system was installed in 1956. Since then the tunnel requires approximately 45 minutes to ventilate the full 7.8 miles. This has created an overall bottleneck these days for BNSF as the number of trains that can pass through the Cascade Tunnel is limited by the time required to ventilate the tunnel.
As part of the ventilation system there are a set of doors that close on the eastern portal. You can see them in operation in this video:
My plan is to animate those doors and use block detectors to trigger them. More on that later.
The Gaynor trestle (sometimes referred to as Nason Creek trestle) was built in 1949 when Great Northern did a realignment to remove a large curved trestle that lead into the Gaynor tunnel. The current trestle made it a straight shot through eliminating 300 feet of mainline and significant curves.
So here is the layout plan for this section:
Grades are roughly 2% through the length of this section of the layout. Nason Creek winds it’s way in and out of the layout and strategic use of view blocks with mountains and trees will hide where the creek enters and leaves the layout. Plus many of those view blocks will provide better layout design areas/elements and key places to take photos. A lot of thought has gone into how best to use this space to get not only location specific shots, but also non-descript mountain scenery photos. The layout needs to double as not only a project to be written about, but as one of a number of different “scenes” where I can photograph n scale equipment from different eras.
So that’s the overview. Next we’ll look at the layout space and the beginning of benchwork.

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Scenic Sub Project Part 1