01-09-2016, 11:55 AM
1452062419-siglengpres.ppt (Size: 3.31 MB / Downloads: 5)
This presentation will cover
A brief history of Signalling in NSW
Very basic principles
The different types of Interlocking Systems in Use
Control Systems
Signal interpretation
Signalling: A brief History
1855: Railway line in Sydney opened
Initial application of token working, then time table working until 1879.
1877: A campaign for a safeworking system was passed
1878: Emu Plains collision occurred just before the new system introduced
1879: Manual Block Instruments introduced
1881: First mechanical interlocking frame at Burwood
1888: Electric tablet
1891: Electric train staff
1910: Power Signalling introduced
1913: Double light system
1915: 3 position upper quadrant signalling
1924: Colour Light signals
1928: All electric miniature lever frame
Signalling: Basic Principles
Track Circuits: Identify the location of trains.
Interlocking: Prevents conflicting train movements, ensures locking of signals and points.
Signals: Visually displays information to train drivers.
Train Stop: Operates in association with signals to prevent trains overrunning an authority.
Points: Diverts trains at junctions or yards.
Signal Box / Control Centre: Operates the train movements
Track Circuits
Track circuits are used to locate trains in the system. Information is feed from the track relay to vital control circuits and/or to the Interlocking to provide train protection and locking.
A basic track circuit shown below is made up of the following components:-
A power source
A variable resistance
A relay
Insulated rail joints to separate rail sections
Interlocking
What is an Interlocking?
In general terms an interlocking is a location where plain track ends and trackwork with points and crossings complicate train movements. These areas are likely to be:-
Junctions where two or more main lines meet.
Complex yards or sidings are encountered. These may be at larger towns or depot facilities.
An interlocking provides for complex train movements and shunting of trains. It provides for the protection of multiple train movements within a localised area.
So the next question is how do you do that?