The layouts are set up to be operating as a shunting/switching challenge - that is to shunt the wagons/cars to a predetermined position in the minimum number of moves.
Please read the instructions first. I know most people will ignore this advice until they have tried the layouts, but they are there if you want them! The instructions page applies to both layouts, some sections are common to both and others are specific.
Because of the self contained script you may disconnect from the internet after the page has opened and still continue operating, useful if you are paying for connection time by the minute.