Automatic Block Signalling (ABS) Flashcards
What is the object of ABS?
*Where two or more trains are going in the same direction, to prevent more than one being in a track section at a time
*On bi-directional lines to prevent trains running in opposite directions being in a single line section at the same time
How is the object of ABS achieved?
*Trains proceeding in the same direction- by electronically securing the fixed signals at stop unless the track ahead is is clear
*On bidirectional lines with trains going in opposite directions- by the signals being electronically controlled by the track circuit and displaying a stop indication (preventing a train from entering from the opposite direction)
What are Station limits in ABS?
(operated by a Signaller)
*the portion of line between the Arriving Home Signal and the first Automatic signal in advance of the Departing Home signal
*Where a Departing Home signal is not provided, it is the first Automatic signal ahead of the Arriving Home signal
What is the procedure when detained at a Home Signal at Stop?
What information will the Signaller give you?
*Sound a long whistle
*Contact the controlling Signaller
*Provide: TDN, Signal post number, Position of train
Signaller will provide:
*Expected duration of delay
*Reason for delay
*If blocking facilities have been applied
If detained at a Home signal at Stop, when must the Train Controller be contacted?
*If the Signaller cannot be contacted
*If not fully satisfied with the cause and duration of delay
*If the delay will exceed FIVE (5) minutes
If detained at a Dwarf or Disc signal at stop, what must a driver do?
What will a Signaller provide?
Driver must:
*Sound a long whistle
*Contact the Controlling signaller
Signaller will provide:
*Expected duration of delay
*Reason for delay
What are the THREE exceptions to pass a Home Signal at STOP?
(ABS)
- Defective
- Track circuited (with NO low speed or calling on signal provided)
- Single line working has been introduced
What is required to pass a defective Home Signal at Stop?
- If it is protecting points, a fouling point or a tramway crossing?
- If it is not protecting any of the above?
- If protecting points etc. a Signallers caution order is needed (points need paper)
- Not protecting points etc. VERBAL instruction from the Controlling Signaller
What details are provided on a Signallers Caution order?
(must check they are correct)
*Name of Signal box
*Date, Time
*TDN
*Destination to and from
*Signal post number
*Signallers signature
How can you receive a Signallers Caution order?
Must you exchange names?
*Handed (default)
*Transmitted
*Dictated
Must exchange names
What are the steps for the exception of Track circuited with no low speed/calling on to enter an occupied section?
*Bring the train to be piloted in to a stand at the signal
*Receive VERBAL instruction and/or a GREEN HAND SIGNAL from the Controlling signaller
*Have a competent worker assist with the move
What is the Authority to pass a signal at stop due to Single line working?
*Be advised by the PILOT
*Have the opportunity to view the details on the Single Line working forms (Pilot will have)
*Verbal instruction from the PILOT to pass the signal controlling entry
Can a pilot authorise a driver past the EXIT of the single line?
NO
The driver must either receive a Proceed aspect or a GREEN hand signal
The exit is under the control of the Controlling Signaller, not the Pilot
What system does the MURL operate under?
Who controls it?
What signals are in the MURL?
*Bi-directional ABS
*Controlled by the Area Controller at Metrol
*All signals are Home signals in the MURL
What is the exception to pass a Home Signal in the MURL?
What authority must be received?
Defective
Protecting points with Route line displayed: Check points + Signallers caution order (transmitted)
Protecting points with route line not displayed: Check/lock points + Signallers Caution order (transmitted)
NOT protecting points: Verbal instruction from Area Controller
