Edges are denoted as:
id1 id2 id3 val
where
id1 is the type of train
id2 is the id number of one station 
id3 is the id number of the other station
val is the number of rails going from one station to the other 


Nodes are denoted as:
id name cx cy
where 
id is the id number of that station
name is the name of that station
cx is the x-geographical coordinate
cy is the y-geographical coordinate