Section 4 - Smith Canal - Part 1

It's time to lay out the Smith Canal section. The layout design given and druthers of this section is identified in Station 4 Smith Canal.

Layout Design Elements

 This section consists of eleven layout design elements:

1. A narrow backdrop partially concealed by a coal distribution company.
2. Waterway bank scenery adjoining the Demaine Yard and the Preacher's Slough section.
   
3. A waterway that begins as a narrow stream (canal), becomes a slough and ends as a small river.
4. A sandbank along the waterway.
5. A single track main line going from the Demaine Yard to Preacher's Slough
6. A beam bridge crossing over a small stream.
7. An embankment that is the roadway for the main line between Demaine Yard and Preachers Slough.
   
8. A concrete arch culvert under the embankment.
9. A multiple span deck plate girder trestle and a concrete beam bridge crossing the waterway. 
10. Two concrete abutments and two concrete piers.
    
11. A tunnel that is bored thru a ridge line that acts as a scenic view block.
    

Section Construction

See the WWSL section construction reference page for the construction technique. 

As this section is a river scene I have modified the construction technique. Instead of using the two 1"x3" girders on the bottom of the section, I need a solid bottom on the section for the riverbed. The 1"x3" girders are replaced by a 2-foot by 8-foot piece of plywood, 3/4 inches thick. The two ends of the section are cut out to permit attachment of the section electrical connectors and section interface bolts.

ROW Design Considerations 

5. The most critical design considerations on this section is curvature of the main line. The turnback curve section width is 60 inches. Technical specification is a minimum 4 inches between track and the edge of the fascia. This restricts the turnback curve to 48 inches (60 - 4 - 4 = 52/2 = 26 ( a 24 inch radius when laying out the curve from the interior).

6. I'm thinking of a ATSF T-rail bridge for this location ... but that may change. See 4.1.9 Smith Canal Bridge S1 (T-rail Beam Bridge) for construction details.

7. The embankment is the second critical design consideration. This location is on top of the WWSL's DCC system and would be a convenient location for a programming track. With this in mind, the programming track 4-inches from the fascia reduces the outside embankment width and depth but allows a full embankment width and depth on the inside. 

This calculation also places the curve radius point 32-inches into the section. This leaves 11 inches for the waterway and far bank scenery. I don't see that as an issue.

8. As a continuation of the Right of Way Engineering Process I would like to engineer a concrete arch culvert. This embankment would be a perfect location. See 4.1.8 Ditches, Drains and Culverts for additional information.

9. A multiple span bridge crossing the waterway. Tentatively this will be modeled as a three span deck plate girder trestle and a concrete deck span. Most of this bridge will be on a curve, with appropriate engineering. I have a Central Valley deck plate girder trestle kit I can kitbatch. See 4.1.9 Smith Canal Bridge S2 for construction details. 

10. A portion of the 2nd Division Right of Way will not be modeled. That section is the Chehelis River Bridge and joint trackage rights with the Milwaukee Road and the Union Pacific between South Montesano and Preachers Slough. The tunnel will act as the unmodeled trackage rights portion of the WWSL. See 4.1.10.2 Tunnel S1 for construction details.

Laying out the Right of Way

I am not going to go into great detail about putting down the roadbed lines. See the Right of Way Reference Page  for the details if you haven't had the fun to do it before. 

Because this section ties into both the Demaine Yard  - Section 3 and the Preachers Slough  - Section 5, some layout of those sections (the main line locators) will need to be done at the same time, primarily the main line locator at the northern-most Preachers Slough curve (6 inches from the fascia ) and the WWSL Arrival.Departure Track at Demaine Yard (4.5 inches from the fascia).  

Essentially you're going to follow this process: 

1. Lay out the programming track at the 4 inch line. 
2. Lay out the main line turnback curve at the 6 inch line. 
3. Lay out the main line to the Demaine Yard Arrival / Departure Track at the 4.5 inch line. 
4. Center the radius at the center of the section width.
   
5. Lay out the transition template line.
   
6. Lay out the main line curves.
7. Lay out the S1 bridge template and adjust as necessary.
8. Lay out the S2 bridge template and adjust as necessary.
   
9. Locate the abutments and piers (to include heights).
10. Layout the sloped river bank on the Demaine Yard/Preachers Slough side of the waterway.
    

 Laying out the turnouts 

A WWSL Common Standard #6 turnout needs to be laid out on the Demaine Yard - Smith Canal module connection. WWSL technical specifications specifically requires at least two inches of straight track from the turnout to the joint, so some adjustment will have to be made.

Roadway Details

• The WWSL 1st Division is designated Class A main line. See See 4.2.11.1 Modeling Technique for High Profile Roadway for details.
• One of the NMRA Model Railroad Engineer - Civil certificate requirements for track work is a super elevation of the track and roadbed on a curve. While the WWSL would not prototypically use super elevation on its roadway, I am going to super elevate the curve between bridge S1 and S2 for certification purposes. See 4.2.4 Super-elevation for Curves for additional information.
  
• The WWSL programming track is designated as retired track. See See 4.2.11.9  Modeling Technique for Retired Roadbed for details.

Right of Way Drainage.  See 4.1.8 Ditches, Drains and Culverts

• Drainage
• Culverts. The
  

In the next blog (Section 4 - Smith Canal - Part 2)  I will discuss the Landform Design Considerations.