I got the idea for this scenario from Overlord1191's thread The Ultimate RO-RO Challenge.
However I don't expect one line in and one line out. Just create a station next to the factory in the center in any way you want. With an effective station and track construction, I expect it to be possible to complete the scenario in about 30 gameyears.
The following cargo pickup/delivery locations are included:
4 Iron Ore Mines
4 Coal Mines
2 Steel Mills
8 Chemical Plants
1 Factory (for the big station)
4 Cities
Industries are set to not shut down or start new. No mods required to run the scenario.
Winning condition is to transport 1 million crates of goods and only one station for the center factory. See how fast you can get this done. I'll post my score here later.