In the MBC 2010 I wanted the signal system to give me useful and clear
information. Therefore, I set it up so that at a divergence (switch; turnout;
junction) the upper signal (aspect) indicates whether you are going to go to the
right and the lower signal indicates whether you are going to go to the left.
Generally I use the “North American Right hand Rule” (we drive on the right side
of the road). So both westbound and eastbound trains generally keep to the right
at a divergence.
I asked a brakeman in the CPR yard near me how it is determined which way a
switch stand is set, that is which way is green and which way is red or, in yards,
yellow. He thought for a moment and replied, the green position is the position
in which the switch stand is normally left, that is the position in which it is
locked. I have used this rule.