[A]  Max aspect for this route is Yellow
[B]  Max aspect for this route is Yellow unless signal ahead is Green
[C]  Max aspect for this route is Red if signal ahead is Red
[L]  Approach released fron Red if signal ahead is Red.  Max aspect is Yellow
[N]  Approach released from Red if signal ahead is Red.  Max Yellow unless signal ahead is Green
[Q]  Approach released from Red if signal ahead is Red
[R]  Main route which is approach released from Red
[Y]  Main route which is approach released from Yellow
[1], [2], [3]  Preference order of alternative routes 
{ }  Intermediate signals which are pre-set for this route

