Chapter 18: Block Instruments, BPAC & IBS Working PDF

(l) Block Instrument Telephone: Block instrument telephone, its flexible cord and the condenser or other means provided for isolating the telephone from the Block instrument circuit are in good condition. The isolation is such that there is no direct path for t...

(l) Block Instrument Telephone: Block instrument telephone, its flexible cord and the condenser or other means provided for isolating the telephone from the Block instrument circuit are in good condition. The isolation is such that there is no direct path for the current to flow from one circuit to the other. (m) Receiver diaphragms are not buckled and are at the correct distance from the pole pieces. (n) Receiver ear piece fits correctly and is screwed tight. (o) When a pair of block instruments of a block section falls in different contiguous Railway/Division, both instruments and their associated equipment shall be maintained by one agency. 18.8.2 Overhauling of Block Instruments: Periodical overhauling interval shall not exceed ten years for Single Line Token Block Instruments and seven years for Double Line Block Instruments and Handle type Single Line Token less Block instruments. Push Button Token less Block Instruments, UFSBI Block panel, and Embedded block working in Electronic Interlocking etc. do not require overhauling. The associated polarised relay shall also be overhauled along with the Block instrument. 18.8.3 Block Earths (a) Block earths and their connections shall be examined at intervals of not more than one month by the Section Engineer (Signal) and at intervals of three months by the Senior Section Engineer (Signal). (b) Block earths shall be tested for resistance at intervals of not more than 12 months by the Section Engineer (Signal) or Senior Section Engineer (Signal) in accordance with Annexure: 19-A3. Where the resistance exceeds 10 ohms, action shall be taken to reduce the resistance by providing additional earths in parallel. (c) In AC electrified areas, two different Earths shall be provided for Discharger and Block Earth. (d) The four Terminal Condenser used in filter shall be connected in such a way that the DC circuit is completed through the plate or foil of the condensers. It shall be ensured that any break in the foil or Earth connection, which might affect the efficiency of the filter, puts the circuit itself out of use. Chapter 18: Block Instruments, BPAC & IBS Working Page 369 of 530  Section 9: Maintenance of Single Line Block - Instructions 18.9.1 Single Line Token Instruments (a) Care shall be taken to see that the safety catch provided near the spring clutch shaft is in position and functioning properly and free to move about the fulcrum without any friction. (b) Token indicator shall be checked to see if it is free to move. The pin shall be oiled once a fortnight with axle oil medium grade to IS: 1628. Effectiveness of 'No token' lock shall be checked. It shall not be possible to take handle to “Train Going To” position when token indicator shows Red. (c) Care shall be taken to see that "Train going to" and "Train Coming From" locks rocker arm is free to move about its fulcrum pin. The locks shall be about 1 mm above the rack; if not, the locks shall be changed. The edge of the lock shall be square. (d) It shall be ensured that all parts of the instrument, which undergo wear and tear, are replaced at the time of overhauling. (e) The locking Pawl shall be checked to ensure that it is correctly shaped, square ended and the width is 9.5 mm. (f) Care shall be taken to see that in the case of Tablet instrument, the tablet holding arm release lever is working satisfactorily and the tablet can be released only after full rotation and release of the instrument handle in the Train Going To" position. (g) It shall be checked that the notches in the rack are correctly shaped and square. Note: (i) RDSO Booklet No. STS/E/BTl/IMI may be referred to for detailed instructions regarding maintenance of Token instruments. (ii) Stipulation as given in section 7 of this chapter may be referred. 18.9.2 Single Line Tokenless Instruments – Push Button Type: The tests enumerated in para 18.5.2 shall be carried out during routine maintenance. 18.9.3 Double Line Block Instruments – SGE Type: Locking assembly shall be replaced during each overhauling irrespective of its condition. It shall also be ensured that all parts of the instrument which undergo wear and tear are replaced at the time of overhauling as per approved instructions. Note: (1) Tests enumerated for Double Line Block Instruments in para 18.6.2 shall also be carried out during routine inspection. (2) Maintenance Schedule for Block Instruments are given in Annexure: 18-MS1 in Appendix I. At stations having heavy traffic the Railways may prescribe more frequent inspections, if considered necessary. Chapter 18: Block Instruments, BPAC & IBS Working Page 370 of 530  Section 10: Maintenance of Block Proving by Axle Counter 18.10.1 Block Proving by Axle Counter using UFSBI Block Panel (a) Various parameters of Axle Counter track equipment and UFSBI shall be maintained within permissible values as per the instructions issued from time to time and as per the OEM manuals. (b) It shall be ensured that various signal levels at prescribed points of electronic equipment are within permissible limits as per laid down instructions. Section 11: Maintenance of Embedded type Block working 18.11.1 Block working built into Electronic Interlocking (a) Maintenance and parameter of Embedded type Block working shall be maintained as per maintenance schedule of Electronic Interlocking and Video Display Unit (VDU) maintenance schedule issued from OEM maintenance manual. (b) It shall also be ensured that all equipment connected with EI related with Block working shall work as per laid down instructions Section 12: Intermediate Block Signalling (IBS) 18.12.1 General Requirements (a) IBS is an arrangement made for increasing the section capacity by splitting of a relatively a long block section into two portions namely rear section and advance section by placement of IBS at the point of near bifurcation, subject to other considerations, such as presence of steeper gradients on approach of the IBS, neutral section, visibility of signals etc. If required, up & down IBS may be staggered to suit the local condition. (b) The rear section i.e. "station controlled intermediate block section" starts from LSS of the rear station and ends at IBS including 400 meters block overlap in that direction. (c) Advance section i.e. "block controlled Intermediate Block section “starts from IBS and ends at home signal of advance station including block overlap in that direction. (d) Track sections both in Rear section i.e. "station controlled intermediate block section" & Advance sections i.e. “block controlled Intermediate Block section” are monitored either by Axle Counter or by Track circuit. (e) Train entry into rear section i.e. "station controlled intermediate block section" is controlled by LSS of rear station in that direction. (f) Train entry into advance section i.e. “block controlled Intermediate Block section” is controlled by IBS in that direction. Chapter 18: Block Instruments, BPAC & IBS Working Page 371 of 530  (g) A Signal Post Telephone (SPT) or any approved type communication shall be provided at the IBS post for communication with the station in the rear. (h) IBS system needs distant and inner distant signal where applicable for pre warning of IBS. (i) IBS works like Class C station & IB Distant signals are to be provided to match with the section signaling. (j) IBS block overlap of 400 m shall be separately monitored. (k) Where axle counters are provided, resetting arrangements are also to be provided. (l) Provision must be there to indicate that a train has passed IBS at “On” Position/blank. (m) IBS system needs panel with various indications and push buttons at each block station pertaining to direction of traffic. (n) IB Signal shall be provided with a marker consisting of a white coloured disc with letter 'IB' in black. (o) Control of IBS lies with the SM of station in rear. 18.12.2 Resetting Operations: There are two types of resetting operations which requires co-operation of the other end Station Master. (a) When a train passes IBS at “On” position/blank. (b) When Axle Counter fails. 18.12.3 IBS system will permit only one train in the entire block section, when a train passes IBS at “On” position or axle counter is not clear even after the passage of the train beyond the axle counter section. Procedure to be followed by the Loco Pilot to pass IBS at “On” position/blank as per GR 3.75: (a) When phone communication is available between IBS and rear station, the loco pilot shall stop his train in rear of the IBS and contact the SM of block station in rear on SPT, then pass the defective IBS, if authorized by SM. (b) When phone communication is not available between IBS and the rear station, the loco pilot after waiting for 5 minutes can go beyond IBS at a speed not more than 15 kmph which should be reduced to 8 kmph in case of inadequate visibility like fog, night conditions etc. The loco pilot should proceed at restricted speed till he reaches advance station. Monitoring is required through indication for IBS blank. Chapter 18: Block Instruments, BPAC & IBS Working Page 372 of 530