I will explain here how to build stations longer than 16 tiles.
You probably noticed that the station name moves while building.
We then say that the station name lies in the gravitation center of the surrounding tracks.
The end of the station can only lie eight tiles away of the center of the station name.
There are some tricks to move that gravitation point.
Just build a normal station 2 tracks wide and 16 platforms long.
Now put 4 extra track pieces on one end.
Build also platforms on these pieces.
Look what is happening with the station name.
It's moving to the right.
Now try to make the station track longer.
20 tiles is no problem now.
If you wish to even make it longer, then you have to breakdown some pieces.
Demolish some platforms just left of the station name.
Note that the station name no moves in the opposite directions.
Now you can build three extra rows of platforms on the right side.
Break down the help tracks and fill up the gap.
Now you have a station which is 23 platform long.
You now can experiment your self with stations that are 3 or 4 tracks wide.
I made a station before with 80 tracks and 6 stages high.
Severous made a single track station 67 platforms long.
So go on and build.
