They cope with scheduling by, 1, making the trains longer and, 2, running the bulk freight behind schedule when there is a conflict.

Its a self-fulfilling prophecy. The major transport task is time-insensitive, weight-charge-sensitive freight. Ergo, if you can save enough money to trim down the charge per ton at the cost of sometimes running half a day behind schedule, that's a good swap. But then you have a rail network that cannot run passenger trains at full speed because they are giving way to a late running coal train.

Suppose you have an Express and a bulk freight running eastbound, and another pair of the same running westbound. The bulk freights hold, one of the Express switches to the bulk freight line, the Express pass, then the bulk freights pass.

Hit the capacity limits for that set-up, and shift to a two-way Express/Local and bi-directional bulk freight line.

Hit the capacity limits for that set-up, and shift to two way Express-Only and two way Local/Bulk.

And for most ROW in the US, four tracks and they are built out.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.