Thursday, 14 December 2017

Demand Based Car Flow - Model Fleet Part 1 - A layout re think

As part of my desire to model the 1920's I have set about developing a car fleet for my railroad. Part of this process is determining freight movement across the layout and in tern determining the umber of cars required for operations.

Tony Tompson has written extensively on car moment, waybill creation and operations on his blog. One series of his I have found particularly helpful is Operations: Demand Based Car Flow.

Using Tony's methodology and generating a distribution schedule of sorts based on the industries on the Yacolt Branch highlighted a problem with my proposed layout. The Yacolt local ended up being over 10 cars long to service all the required industries if I modeled Homan through to Yacolt.
At the same time i have been struggling to fit all Homan through to tunnel 1 on 1 deck of the layout.

My aim for the layout was to generate enough traffic that I can run one freight local a day and additional passenger service / dedicated log trains. Using my sample schedule I found that restricting the layout to service only industry past Battle Ground the car lengths averaged out at 6 cars. An acceptable length for my layout.

Sample Distribution Schedule -  showing cars arriving on layout from staging.
Using my distribution schedule caused a re think of the track plan and a decision to model the layout from Battle Ground through to Yacolt and the Murphy Lumber Co.

This will result in the following trains:
- Yacolt Local - Departing Staging (Vancouver junction) through to Yacolt and return
- Daily passenger service AM and PM service
- Murphy Log Trains

As a result its back to the drawing board and track planing for the lower deck with the new school of thought.

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