When I began creating the Siskiyou Route I needed a means of determining what the mileage was at any particular place. I wanted the Mileage Posts on the Route to agree with those along the actual railroad. So I created a spreadsheet that would do it for me. The more that I used the spreadsheet, the more I added to it.
One of the things that I insisted on was that mileage shown in the Northwest Region Timetable for all of the various locations would be the same as found on the Siskiyou Route. I simply created a small factor to the data in the spreadsheet that "tweaked" it so that the two sets of data would agree. This provided me with a means of determining exactly where along the track each MP (mile post) needed to be placed.
The sheet includes every piece of mainline track and it's "centerline" length. As each piece of track was added the sheet kept a running total of how far the Route had progressed. When the final track was placed the sheet provided an exact length from Black Butte in California to Springfield Junction just outside Eugene, Oregon.
Along with the mainline, I also added all of the sidings, their lengths and names, tunnels, bridges, trestles, switches, DED's, signals, speed limits, and so on.
What I ended up with, including the Dorena branch line, the White City branch line, and the Yreka branch line was a spreadsheet that had 5,925 rows of data.