Double Line Electrical Block Instruments PDF

CHAPTER II DOUBLE LINE ELECTRICAL BLOCK INSTRUMENTS – DESCRIPTION AND METHOD OF OPERATION 2.01. Type of Instruments – Double Line Block Instruments in use on Eastern Railway are of three position Lock & Block type. 2.02. Description of Instru...

CHAPTER II DOUBLE LINE ELECTRICAL BLOCK INSTRUMENTS – DESCRIPTION AND METHOD OF OPERATION 2.01. Type of Instruments – Double Line Block Instruments in use on Eastern Railway are of three position Lock & Block type. 2.02. Description of Instruments – The various parts of the Block Instruments, as marked in the Diagram below and their functions are described below :- From the illustration it will be seen that the instrument is provided with :- (a) Two needles, an upper and a lower indicating ‘Train on Line’ ‘Line Closed’ and ‘Line Clear’ on segments coloured red, white and green respectively. (b) A Commutator (c) A Bell Plunger (d) A Block Bell 2.03 Needle indications – The needle indications are :- (i) Line Closed (needle vertical, on white segment) (ii) (iii) 4  The “Line Closed’’ indication is that shown when there is no train in the Block Section and “Permission” has not been given for any train to enter it. The “Line Clear” indication is that shown when permission has been given or received for a train to enter the Block section. The “Train on Line” indication is that shown when the Block section is occupied by a train. 2.04. The Upper Needle – The indications of this needle refer to trains leaving the station and give a visual indication of the condition of the Block section in advance. It is electrically controlled by the Station Master at the Block station immediately in advance and its indication can only be altered by him. The indications of the upper needle corresponds with those of the lower needle of the corresponding instrument at the station in advance. 2.05. The Lower Needle – The indications of this needle refer to trains approaching a station and give a visual indication of the condition of the Block section in rear. It is worked entirely by the Station Master of the station at which the instrument is located. The indications of the lower needle correspond with those of the upper needle of the corresponding instrument at the station in rear. 2.06. Relation of the needle indications to Block sections – Two Block Instruments are provided at each station, the Up instrument for signalling trains to and from the next Block section in the Up direction and the Down instrument for trains to and from the next Block section in the Down direction. The lower needles indicate the condition of the Block sections for trains approaching from either direction and the upper needles the condition of the Block sections for trains proceeding from the station in either direction. 5 2.07. The Commutator – The turning of the Commutator operates the lower needle of the the cabin immediately in rear. (a) The Commutator (like the needles) has three positions – (i) Normal position : when the lower needle of the Block Instrument indicates “Line Closed” and the pointer on the face of the Commutator in vertical (Segment-white). (ii) Line Clear position : when the lower needle of the Block Instrument points to “Line Clear” and the pointer on the face of the Commutator is ected to the right (Segment-Green). (iii) Train on Line position : when the lower needle of the Block Instrument indicates “Train on Line” and the pointer on the face of the -Red). (b) The Commutator is locked in the “Train on Line” position only if the “Line Clear” indication has been previously given. It remains locked until the train clearing the station operates a treadle or a track circuit or an Axle Counter and the reception/last stop signal has been placed to “On”. If, however, the Commutator is turned direct from its normal (Line Closed) position to “Train on Line” it does not become locked. (c) The commutator shall be turned immediately the Bell Code (GR-14.05) has been signalled and before releasing the Bell Plunger. The Bell Code shall always be given before turning the Commutator. 2.08. The Bell Plunger – The plunger is placed in the centre of the Commutator and when depressed gives one beat on the bell of the corresponding instrument at the other end of the Block section. The Bell Plunger shall only be employed for signalling trains on the prescribed Code of Bell signals. 2.09. Block Bells – These bells are provided to give an audible signal by means of the prescribed Code of Bell signals. (GR-14.05)) 2.10. Method of governing the movement of trains from Block station to Block station. – In the case of each train, after the “Call Attention” beat has been given and acknowledged by station in advance, before any other operation on Token or Block Instrument is made, the names of stations working together shall be exchanged on the telephone, as an assurance that the correct stations are in communication. 6  The following is the sequence of operations for signalling train at either A, B or C class stations – Taking three stations X, Y and Z and a train travelling from X to Z and proceeding on its journey the Block sections being clear and the Block Instruments showing “Line Closed”, then – Station X Station Y Station Z (1) Sends “Attention Signal” (2) Acknowledges to Y (one stroke/beat). “Attention Signal” to X (one stroke / beat). (3) Attends telephone. (4) Attends telephone. (5) Gives name of station on (6) Gives name of station telephone. on telephone. (7) Asks Line Clear for the (8) Gives Line Clear on train on telephone giving telephone repeating the number and the number and description of the train description of the train with the Private Numbers. supported by a Private Numbers. Note :- Exchange of Private Numbers while seeking and granting Line Clear should not be adopted in case of suburban and quadruple line sections. (9) Sends “Attention Signal” (10) Acknowledges to Y. “Attention Signal” to X. (11) Sends “Is Line Clear” signal to Y according to the description beat prescribed in the bell code (Two beats). (12) Acknowledges “Is Line Clear” signal by an exact repetition and on the last beat of the signal turns the commutator of its Block Instrument to the right indicating “Line Clear” (Two beats). 7  Station X Station Y Station Z (13) Immediately after receipt of the last beat of acknowledgement and on seeing that the upper needle of its instrument now points to “Line Clear” takes off departure signal for the train. (14) Sends “Attention Signal” (15) A c k n o w l e d g e s to Y after departure of the “Attention Signal” to X. train. (16) Sends “Train entering (17) Acknowledges “Train section” signal to Y. (Three entering section” signal beats). by an exact repetition and on the last beat of the signal turns the commutator of the Block Instrument to the left (Three beats). (18) Returns the departure (19) Sends “Attention (20) Acknowledges signals to “ON” after the Signal” to Z. “Attention Signal” to Y. train has passed the last stop signal. (21) Attends telephone. (22) Attends telephone. (23) Gives name of station (24) Gives name of station on telephone. on telephone. (25) Asks line clear for the (26) Gives Line Clear on train on telephone telephone repeating giving the number and the number and description of the train description of the train with the Private supported by a Private Numbers. Numbers. Note:- Exchange of Private Numbers while seeking and granting Line Clear should not be adopted in case of suburban and quadruple line sections. 8  Station X Station Y Station Z (27) Sends “Attention Signal” (28) A c k n o w l e d g e s to Z. “Attention Signal” to Y. (29) Sends “Is Line Clear” (30) Acknowledges “Is Line signal to Z according to Clear” signal by an the description beat exact repetition and on prescribed in the bell the last beat of the code. signal turns the commutator of its Block Instrument to the right indicating “Line Clear” (two beats). (31) Immediately after receipt of the last beat of acknowledgement and on seeing that the upper needle of its instrument now points to “Line Clear” takes off departure signals for the train. (32) Sends “Attention Signal” (33) A c k n o w l e d g e s to Z after departure of “Attention Signal” to Y. the train. (34) Sends “Train entering (35) Acknowledges “Train section” signal to Z. Entering Section” signal by an exact repetition and on the last beat of the signal turns the commutator of its Block Instrument to the left. (36) Returns the departure signals to “ON” after the train has passed the last stop signal. (37) On the train clearing the rear block section, sends “Attention signal” to X. (38) A c k n o w l e d g e s (39) Sends “Train out of “Attention Signal” to Y. section” (Four beats) signal to X and on the last beat of the signal turns the commutator of its Block Instrument to normal “Line Closed”. 9  Station X Station Y Station Z (40) Acknowledges “Train out of section” signal to Y by an exact repetition (Four beats). (41) Returns the departure signals to “ON” after the train has passed the last stop signal. (42) On the train clearing the rear block section, sends “Attention signal” to Y. (43)A c k n o w l e d g e s “Attention Signal” to Z. (44) Sends “Train out of section” signal to Y and on the last beat of the signal turns the commutator of its Block Instrument to normal “Line Closed” position. (45)Acknowledges “Train out of section” signal to Z by an exact repetition. 10