I wanted every train to be returned to its original starting position after the completion of timetable operations. I had already decided that I would like every train to run once in each time timetable cycle, although later I allowed the local goods and milk train to remain in their depots for a complete cycle to allow for loading and unloading. Because there were four intermediate passenger trains, I wanted there to be one per sub-cycle for each timetable cycle. To allow them to run in a different order for each cycle, there would need to be four cycles in total.
There were some other conditions that I wanted the timetable to fulfil. Firstly, for each sub-cycle, there should be two parts. During the first part, the branch train would run in the up direction, the 2-6-4T would run on the main in the down direction during the first sub-section, then in the up direction during the second, etc. During the second part the branch train would run in the down direction and there were two alternatives on the main line. In one case prairie would run in the opposite direction to the 2-6-4T and a long-distance freight would run the other way. In the other, a local freight (goods or milk) would run in the opposite direction to the 2-6-4T and express passenger would run the other way.
To see how this would work I constructed the following manifest. Notice that I have numbered the sub-cycles continuously from 1 to 16.
Sub-cycles 13 and 14 are slightly different, to allow for the local freight trains to return to their original starting position and 16 has an express passenger replacing the heavy freight used in 13.
After the manifest I needed to check whether this could all be achieved using eight storage loops at each end of the layout. The following feasibility matrix was used.
The numbers across the top represent the sub-cycles and the numbers in the table indicate the train in a particular loop at the end of a sub-cycle. So Sub-cycle 0 represents the starting position. It was essential that, at the end of Sub-cycle 16, the same trains were in each loop as at the start. In turn, this allowed me to propose the following routes from up to down and vice versa (including routes commencing or terminating at local depots).
After milk depot operations, it is necessary to invoke the Branch Main route (27) to ensure that the up main line is set to normal up operations. The Goods Reset route (30) serves the same purpose on the down main line. I will show the routes and associated points in a later posting.