So,

Here is a design that captures the feel of Southern Pacific's Willamette pass route over the cascades.

I was always fond of the  Tehachapi Loop Layout, that was built for a hobbyshop display, and featured in the June 2000, issue of Model Railroader.  It had the all the flavor of  the tehachapi Line,  Bakersfield, with a yard, and engine servicing to show off your locomotive collection, it had the climb  up the mountains the sweeping 180 degree curve at caliente, and  as it passed though a tunnel, came out the other side of the backdrop into the famous Loop, around the mountain, and back  towards the bakersfield Side of the layout. For N scale on a 4x8 with some end triangles, It captured the feel of hauling SP or AT&SF tonnage over the loop.

What I was trying to do was the same but with  SP's cascade Line..   I thought about having the line start off at Eugene yard, but oppted to go with Oakridge.

At Oakridge there is a small yard, and  engine tracks to hold your fleet of helpers. also I added a very condensed version of the mighty Pope & Talbot Mill to do some switching. I also took some licence to add a team track on the edge of the yard located along the top edge.

Oakridge would be the Helper terminal for trains going up the Hill. as a train exits the  Helix/staging, it would slow and stop to pick up either headend or rear helpers. then the train would  start the climb to the summit. track speed along the line is between 20-and 25mph

leaving Oakridge.. the line crossed Salmon Creek Bridge,  easily modeled with MicroEngineering  plate girder deck bridge kits.. The line then passes the would be location of Pryor,Mccreedie Springs, and Heather Sidings, but since  its only 40 sqft of layout space.. these were omitted.  

Like the prototype, the trains will cross the Salt Creek Bridge over namesake creek on a 180 degree curve.. this is one of the Layout design elements I wanted to include, it is the most photographed scene on the line. with its 15"R  and many tall trees,  it should look great, the bridge is easliy contructed from Micro egineering  tall steel viaduct kits. here the railroad crosses highway 58, and salt creek.

now the line climbes up the south side of the canyon per the prototype.. passing through trees and tunnels,  the only siding on the Middle level of the line is Wiccopee, I  would have like to included it, but I didnt think a 5' long siding would work, or look well. 

Trains enter tunnel 20, which pops it out on the other side of the layout as tunnel #17. still climbing the "south middle leg" of the canyon, the trains pass through the "slide" area.. this section of land has been slowly sliding down the hill, many track realignments have taken place.. SP did a masive drainage project in the area, and has all but stopped the sliding. still there is a 15mph slow order in the area.  

The trains enter tunnel # 16, this  tunnel as on the real deal, is built on another 180 degree curve.

from tunnel #16 trains are now on the top level of the route.  The top represents all the sidings on the upper level of Willamette pass. I tried to incorperate a little of each.   Feilds, Cruzatte, Abernathy, and  Cascade summit.  Located on the "summit" siding, is Cascade creek, found at Cruzatte, as well as the old water tower from steam days. the siding travels along rock cuts, and into a rockshed/snowshed even tho there are no double track sheds on the line, I wanted to incude one to hide the tracks entering the helix.  from the shed, trains enter a double track 3 loop helix back down to oakridge.

Trains,  

Trains on the line could be a great selection, I dont know if  steam engines would work will with the sharper curves. but early black widow F and geeps would be right at home.  the 1960's saw many colorfull units on the the hill, mixed frieghts, autoracks, reefers blocks, and Lots of lumber.  SP ran the  Shasta daylight up untill amtrak took over. in more modern times, SP's vast fleet of tunnel motors would look great haulling forrest products up the hill, and emptys down to oregon's valleys. Amtrak runs the Coast starlight  both directions  early  versions of  train #11 an 14 could be F40ph's with herritage cars, or  superliners in phase II or Phase III,  with kato's  amtrak equipment you can run a complete version of  2 F40's, a baggage car or two, step down ex Hi level coach, 2 sleepers, a diner, lounge cafe, and 4-6 coaches. Oakridge Is also the storage yard for work trains and snow removal trains. For may years a daylight inspired Dinner, Named Snowflake was stationed here, along with a Jordan Spredder. Trains of ballest cars, tunnel repair, and water cars have been know to be stored here as well.

If your a fan of the Union pacific, this  would work just as well, though oakridge  was not used as a helper terminal that much, still getting your frieghts to Californa with DPU's would be fun.   The UP tends to place helper locomotives on at Eugene and run them to Klamath Falls. you can see  sets of locomotives 6-12 of them as a light power move from Kfalls back to  Eugene to help more loaded frieghts to california. In general many of the loaded trains headed to California, and empties  returned to Oregon for  forrest products. this dosent mean no loads went to oregon.. just that Oregon Ships allot of forrest products out of state. 

Operations

With the extra long siding that makes up summit-helix-oakridge one could have a couple decent sized trains. each stopping to pass each other at oakridge or  "Summit"  The layout could be set up for someone that just likes running trains though great scenery. Or you could make it a operations themed layout with helper  crews, and a local swiching the mill and team  track, and everyone gets out of the way for #14, and 11. 

down helix trains can take the inside  track, which is a bit steeper than the outside track, uphelix tracks would take the "main"  with this helix set up for stagging, one could have lengthy trains or several shorter trains  stacked behind each other.  With one side open to the helix you can see your trains as  they are on the loops.

The Layout,

The yard at oakridge is near flat. the  grade begins as you cross HWY 58 its about a 2.40% grade all the way to the top. half a percent steaper than the real line. but I wanted  the trains to look like they were climbing.  the track height reaches 7.5" above Oakridge yard.   The Helix is a 13.75"R and 12.5"R  each loop gains 2.5" on a about a 3% climb... yes I know my ruling grade is on a helix, and hidden.. but its the price to pay for a small layout like this.  If you keep trains short, you should be fine.  make sure your N scale cars are  propely weighted. and your track in your helix is flawless. The creeks, salmon, and salt, would have to be modeled a few inches lower to get the salt creek Viaduct to look correct.  with the ME  towers Kits you would have to cut off the bottom 1/3 to get the right height of the bridge.  As for  layout contruction. you could use Woodland scenics foam risers, and  pink foam insulation  to make a lightwieght  layout on a frame of 1x4's. or for something more perminant try cookie cutter with wooden risers, or Joef's strip laminent. with cardbord and tape for scenery construction. see his fantastic video's on it!  The run on this layout is suprizingy long for only 40 square feet. from the bottom of the helix at the road overpass to the summit siding in the snowshed is about 410" or 35 feet. or about one scale mile. not bad for a  smaller layout!

Track,

this plan was designed with atlas RightTrack freeware.  The sharp curves of 11.5"R are located in the tunnels, the viewable track is 13.75 and 15" R.  to get the feel and look of real track I used atlas code 55 template for the design, I would construct the curves with superelevation to look good. for switches you can come up with whats  good for you, under table swich machines, ground throw..  its all good..dont forget to paint your track a nice rusty brown, I find pollyscale roofbrown is a good choice. Ties along the line are still wood, concrete ties have not be introduced that i know of as yet. (i could be wrong tho)

Scenery

For construction, I would use JoeFs method,  plaster, cement, vermiculite.  paint, zip texture, and plant a few hundred trees, I tried to "plant" trees on the layout plan to block views. such as the mill, from salt creek bridge, as these two LDE's are many miles apart.  For structures there are very few, which will give you time to make the hundreds of tree's to get the layout to look like Oregon.  The  bridges can be made as stated above from ME kits . The through truss bridge going to the mill can be made from the new central valley  kits , or maybe a kato bridge with some work to replace the track to code 55.  The road bridge over Oakridge yard  can be modeled with anytype of concrete road bridge kits you see fit, and this hides the  tracks coming on and off layout.

This is my favorite lines to railfan, and plan layouts, this one  I could build, but I might pass up, and plan a differnt  design, still this holds the Flavor of Southern Pacifics Cascade crossing. hope you enjoy looking it over. If you think this might be a layout for you. Please let me know I would love to see it built.

Jason S