I've just uploaded a new and quite challenging switching scenario for the Industrial Interactive route to my website. It has a BN theme and the work order includes switching at the Chemical Plant, it'll take about an hour to complete if you're quick. You'll be handling several cuts of cars that barely fit on the runaround track, and many sidings are blocked by cars -- a real puzzle!
You can download it here: http://golden-age-rails.com/rwscnrio.html
[Edit]: You can also download a rail vehicle swapping tutorial on my website.
Please note: if you swap rail vehicles in this scenario, you should be careful to use cars of the same length (or shorter).
This scenario is set up as a freestyle switching scenario, you get only four marshall instructions which you can complete in any way and order you like. Just make sure all consists end up on their destination sidings at the end and you'll be able to complete the scenario with the green checkmark. To get the most fun out of it, pick up all the inbound cars from the yard at the beginning, add them to the back of your engine so you don't have to push a long train without a caboose through the middle of town, and then figure out the runarounds and switching moves at the plant as you get there. All drops and pick ups at the plant can be done in a single round trip, you'll just need need to be creative with the switching at the plant.
Have fun!
Michael
Some screenshots below. Caution, these screenshots may contain spoilers!
