I calculated it long ago but I can't find the original notes. It can be extrapolated from the default 74 ticks a day (and the distance represented by 1 tile) to ((33 ticks per cpu second) * 86400) in my patch, and I think it came about a tile size of around 8 metres or so. Too long ago to be sure, but I found a time speedup of 4x compared to realtime was a good compromise. It made transport by slow vehicles viable to keep factories running, or a lot less were needed to keep up deliveries. The newer setting for minutes per tick made realtime possible eventually. I had it set to 11, I think.

It was also quite easy to limit production (or passengers) in the code from 06:00 to 20:00 a day for a little extra realism with either emptying a station during the night or have no traffic servicing buildings. Even weekends are possible. Warehouses would be a nice addition.