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Petone - The Control Machine In the 1950s when the Petone panel was commissioned personal computers were science fiction. The panel on the first floor of Petone Box is the equivalent of a Graphical User Interface (GUI), controlling the relay logic located on the ground floor and also in some field locations. |
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Panel Diagram Switches Switch Layout Bells Switch In/Out Buzzers |
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The Petone Panel
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Diagram
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A down train is at Ava and another train is at Melling. |
Note the quick and simple methods used to make changes to the diagram. The yellow paper hides the now lifted Fletcher siding. |
Switches
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47 points are in the reverse position and are free because no signal has been cleared over them, there are no track circuits occupied and 48 points are normal. |
Signal 77 has been cleared for a train on the down main, locking 48 points (the crossover) normal. When a train passes 77 signal the indication will change from Green to Red. If the Down Main is switched-in the indicator light will flash, meaning that the lever must be put to stop. If another train is to be signalled on the down the light is allowed to flash until the train has cleared the overlap; the lever is then restroked. |
Switch Layout and Signal/Point Numbering
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The numbering of the points and signals is based on the position of the switch on the panel. This explains why signal 14 is followed by 17 but signal 11 was followed by 13. |
Bells
Notifying Trains. Originally information about trains was passed from signalbox to signalbox by bell codes. When a signalbox switched-in the box was connected to the bell and phone circuits.The bells were out of use by ??.
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![]() (Above) This indicator reminded the signalman which box the bell circuit was connected to. The indicator did not perform any switching function. The slides were moved to the left to display in turn Woburn, Taita, Trentham & Upper Hutt. ![]() |
Switch In & Out and Indications Check
Up & Down Mains. The Up and Down Mains can be switched in and out independantly. When a main is switched-out the running signals display illuminated A-lights and operate automatically. |
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Buzzers
When the Down Main is switched in a buzzer sounds when the approach track circuit is occupied. The same applies on the up main. |
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Last Updated: Wed Feb 29 17:25:49 NZDT 2012