Red shunting signals are found in small-arm semaphore ( the arms are about the same size as those of permissive signals ) and disc varieties ( the disc is about 12 inches / 30 cm diameter ).
12.
Furthermore, a permissive signal may be marked as a "'Grade Signal "'where a train does not need to physically stop for a " Stop & Proceed " signal, but only decelerate to a speed slow enough to stop short of any obstructions.
13.
In the Australian states of New South Wales, Victoria and South Australia, as well as New Zealand, a permissive signal has the lower set of lights offset ( usually to the right ) from the upper lights; in Victoria and New Zealand, an absolute signal displaying a red or white " A " light is also treated as a permissive signal.
14.
In the Australian states of New South Wales, Victoria and South Australia, as well as New Zealand, a permissive signal has the lower set of lights offset ( usually to the right ) from the upper lights; in Victoria and New Zealand, an absolute signal displaying a red or white " A " light is also treated as a permissive signal.
15.
Changes in assumptions about train performance, and changes in operational rules also had notable impact on system throughput, such as the prohibition of movement of trains past permissive signals at restricted speed ( No Key-By without permission from Control Center . ), the system consists of about 14, 850 signal blocks, 3, 538 mainline switches, 183 major track junctions, 10, 104 automatic train stops, and 339, 191 signal relays.
