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6 Cards in this Set
- Front
- Back
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What are double line systems? |
Two sets of tracks running parallel between two block signal boxes. One track set is used for trains travelling towards Melbourne (UP lines) while the other track is used for trains travelling away from Melbourne (DOWN lines). The left hand track is the correct track for trains to enter and travel upon. There are two types of double line systems: - double line block - double line with automatic block signalling (ABS) |
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Craigieburn to Seymour What is the object of the double line block system? |
The double line block safe working is achieved by using block instruments and fixed signals. A two position signal is used as the drivers authority to enter the section and proceed to the signal box at the opposite end of the section. Once a train has entered the section, another train is not permitted to enter the same section until the first train has arrived complete at the opposite end. The object of the double line block system is to prevent more than one train being in the same section between two block signal boxes on the same line at the same time. |
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What are the station limits on a double line block system? |
Station limits on the double line block system is the portion of line between the home signal and the starting or departing home signal. |
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North Melbourne to Sunbury What is the object of double line with automatic block signalling system? |
Three position automatic signals are placed at intervals between signal boxes. The number of trains that can travel in the track sections between two signal boxes is limited to the number of signals. The line between each automatic signal is called the track section. The object of the double line system with automatic block signalling is to maintain a safe interval between trains by preventing a train entering a track section that is already occupied. |
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What are the station limits on double line block with ABS? |
The line between the home arrival signal and the first auto signal. |
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What is the object of the Manual Block Working and how is it achieved? |
Following the failure of the double line block system, the object of manual block working is to prevent more than one train in the block section between two block signal boxes on the same line at the same time. This is accomplished by the proper working of the fixed signals - the STOP aspect must always be displayed at all fixed signals and only be placed to PROCEED when a train is to enter the block section and the line ahead is clear. The employee who operates the block working must also work the fixed signals-signaller. The signaller must not permit a second train to enter the block section in the same direction until the train controller has granted permission-after confirming the previous train is clear of the section ahead. The blocking facility must not be removed until it has been confirmed that the first train has arrived complete at the block signal box in advance. |
