It is said that the left hand running on the C&NW came about when it double tracked the Chicago commuter area.
The story goes:
All the depots had been constructed on the north or east side of the tracks (this would be on the left hand side of the inbound trains.)
When the line was double tracked the additional track was located away from the depot. How inbound commuters needed shelter while awaiting their trains so the Chicago bound trains were run on the track closest (the left hand track) to the depots. The returning commuters would get off their trains and head home immediately.
BN