The following example shows how the Double Colour Light Signalling system in Sydney works.

                                               R
               G       G       G       G       R      R      R               G
___Train_2-->__G_______Y_______Y_______R_______G______R______R___Train_1-->__G
                      ^^^     ^^^             ^^^
                 These signals are sometimes omitted

				Green Green   Full Clear, or "2" - Minimum of 2 signals before a stop signal.
Auto		Home

				Green Yellow   Preliminary Medium, or "1¾" - Minimum of 3 signals before a stop signal, or 2 to a turnout.
Auto		Home

				Green Yellow   Medium, or "1½" - Minimum of 2 signals before a stop signal, or 1 to a turnout.
Auto		Home

				Green  Red   Caution, or "1" - Expect next signal to be at stop.
Auto		Home

				Red  Red   Low speed. Maximum 25 km/h. Green
Auto		Home

				Red Red   Stop
Auto		Home

Yellow Yellow   Medium Turnout - next signal is not at stop

Yellow   Red   Caution Turnout - Expect next signal to be at stop

The following animated GIF was designed and created entirely by Matt Smith

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