[K]  Approach release from Red when next signal is Red, this route clears to Green only
[L]  Approach release from Red when next signal is Red, this route clears to Yellow only
[M]  Approach release from Red, this route clears to Yellow only
[N]  Approach release from Red when next signal is Red, clears to Yellow, clears to Green only when next signal is Green
[Q]  Approach release from Red when next signal is Red
[R]  Main route which is approach released from Red
[1], [2], [3]  Preference order of alternative routes 
{ }  Intermediate signals which are pre-set for this route

