Modeling Interest 3 - Traffic

In Layout Design Process 4 - Railroad Modeling I identified that the layout design process can be broken down into three primary functional areas: Concept, Structure and Layout Detail. In this blog we will discuss the third of the five elements of Concept 2) Specific modeling interests - Traffic.

The traffic element includes 3 elements: 1) the types of trains to be run (streamline passenger v commuter, merchandise fast freights v local freights v mixed trains), 2) the traffic density (the number of trains to be run during an operating session), and 3) the length of trains to be runas indicated by Modeling Interest - Railroad Operations.

Types of trains to be run

• Passenger. Logging operations had logging camps near logging reload locations. Movement to cutting sites was often done by home made speeders or by flat car. The railroad would on a regular basis transport loggers lining in the camps to town on weekends. In the mid-50s logging camps were becoming obsolete as trucks became more prevalent and more loggers were living in local towns and commuting to cutting sites. My passenger modeling consideration suggested a local (perhaps mixed service) between Montesano and the logging camp.

• Freight. Industry practice on short lines and logging railroads suggest locals, usually run as extras, operating based on the demand of the customer. I would anticipate at least two freight trains serving coal and stone customers, one freight train serving the lumber company, and one freight serving the paper mill.

• Yard Switching. Freight traffic would move through a central yard, located near the Class 1 interchange locations. The yard would classify the incoming cars in five sorts: 1) Interchange to NP, 2) Interchange to MILW, 3) Interchange to UP, 4) local freight north and south bound, 5) local switching. Yard switcher would usually do local switching within yard limits.

• Interchange. The Northern Pacific employee timetables listed a 75 car siding at Montesano, Washington. MILW and UP interchange tracks are located at Melbourne WA. This would suggest 3 transfer runs daily.
  

Traffic Density

Traffic density is defined as the amount of freight moved. Small amounts are considered light density, large amounts are considered heavy density.

At the industry level, the size of the industry (in terms of cars received and shipped), the volume rate (cars loaded or unloaded per day) and the demurrage rate( the number of days the industry had to load or empty the car before a daily charge was made) often determined the size of the industry's siding. A small industry with a small volume rate would rate a small siding with on call servicing. A medium industry with a large volume rate would rate a small siding with daily servicing or a large siding with alternate day servicing. Large industries with mismatched sized sidings would require multiple servicing per day, often suggesting a dedicated railroad switcher assignment, or an industry owned switcher.

Heavy Industry

• Logging. Movement of logs from the reload site to the sawmill would be by logging train. Logging railroads in the Grays Harbor area loaded between 60 and 120 flat cars per day. Based on the size of the sawmill I anticipate daily activity would be 24 logging cars inbound, and 10 boxcars, flat cars or gondolas outbound daily.

• Pulp and Paper. The paper mill would see a variety of loads and empties - chips in open hopppers and gondolas, chemicals in tank and boxcars, finished paper in boxcars, fuel in hoppers and gondolas. Chips would be loads in and empties out. Chemicals would be loads in and empties out. Finished paper would be empties in and loads out. Daily activity would be 15 to 20 cars.
  

Medium Industry

• Coal Mine. The coal mine would see empty hoppers and gondolas in and loads out. Occasionally the coal mine could receive supplies in boxcars and flat cars. Based on the size of the coal mine I anticipate daily activity would be 14 hopper or gondola cars inbound and outbound.

• Sand and Gravel. The sand and gravel processing area would see empty hoppers and gondolas in and loads out. Based on the size of the sand and gravel plant I anticipate daily activity would be 4 hopper or gondola cars inbound and outbound.
  

Light Industry

• Creosote Plant.The creosote plant would see loaded gondolas and flat cars of raw materiels of cedar poles and unfinished railroad ties either daily or several times per week. The plant would also see a loaded tank car, probably weekly.

• Pole Yard. The pole yard would see empty flat cars or gondolas in and loaded flatcars or gondolas out, probably one or two a week.
  

Length of Trains

The WWSL is a class III shortline. Based on the overall size of the layout, I determined that the longest train would be no more than 8 50 foot boxcars, with no more than 75% of the cars being delivered to any single industry.

The next blog will discuss locomotives and rolling stock interests.