Mackay Sugar Cane Central Traffic Office

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Traffic on all four networks is controlled from one central location at Pleystowe mill. The four traffic officers (TO) on duty sit in one common soundproof room with a traffic supervisor. Each TO has a console with a schematic of his rail network projected onto a screen on the wall in front of him. This screen, known as the Electronic Mimic Board, is a computer programme that has some basic rules of train control built in. The following is a very simplified version of how trains are controlled. Each train has a head and tail icon which allows the TO to move trains around the network and display what section of track each train occupies. When the head of a train is cleared into the next clear section, the traffic officer simply picks up the head icon with the computer mouse and drops it on the node where he is clearing the train to. If this section is unoccupied, a transaction number is generated which is issued to the train crew as their authority to proceed. The train crew repeats back the transaction number and the limit of the authority for confirmation by the TO that they have received and understood their authority. If the track section is occupied, the head icon can not be placed on the track. The programme will reject the movement, return the icon to where it came from and not issue a transaction number. The tail icon remains at the other end of the trains limit to ensure no following train can enter the occupied section until the preceding train has cleared it.

A TO station also has three computer screens for the following tasks:-
1. Multiple camera views of the empty and full yards at the TO’s respective factory
2. Schematics of the empty and full yards showing capacity and status of each line in the holding yards
3. Runs a programme called TO Tools whereby the TO keeps track of empty deliveries, full bin pickups, train crewing and scheduling. See Traffic Office 1 photo

The TO has a UHF radio as his main point of contact with the train crews. A train can move from one mill to another through a handover process in an area between two networks known as a Block Zone. This border between two networks is controlled by one TO and train crews must change radio frequency accordingly to enter a “foreign” network and come under the control of a different network TO.
The Racecourse Mill network console. The networks projected onto the wall are (from the left) Racecourse network, in the centre the Pleystowe Mill network and the network on the right being Marian Mill network. The monitors on the desk in front of the Racecourse TO are (from the left) Video monitor of the Racecourse full and empty yards, TO Tools computer and then the yard schematic screen. The Racecourse Mill network console
Traffic Office 1
This shot shows the 4th network on the left of shot. The serene scene is not part of any stress relief programme! The EMB computers must be shut down and rebooted once a day. Here the Farleigh Mill network is being rebooted and will be back online shortly. This shot shows the 4th network on the left of shot
Traffic Office 2

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