CHAPTER -XIII

OVERHAULING AND TESTING OF INTERLOCKING

(MECHANICAL ELECTROMECHANICAL AND RELAY INTERLOCKING)

GENERAL REQUIREMENTS

13.1 Interlocking Frames

13.1.1 All interlocking frames, interlocking key boxes and Station Master's Slide Control frames shall be overhauled and tested periodically as per requirements contained in Section 'A' and 'B' respectively of this Chapter. The records of the same shall be maintained as per Section 'C' of this chapter.

13.1.2 The Electromechanical Frames shall be overhauled and tested periodically as per requirement contained in Section 'D'.

13.2 System and Equipment Testing

13.2.1 Relay interlocking and solid state interlocking installation shall be tested as indicated in Section 'E'.

13.2.2 Periodical testing and overhauling of electrical signalling equipment used in signalling installations shall be done as per requirements contained in Chapter XIX.

13.2.3 Periodical testing and overhauling of mechanical signalling equipment used in signalling installations shall be done as per requirements contained in Chapter XII.

SECTION 'A' - OVERHAULING OF INTERLOCKING FRAMES, INTERLOCKING KEY BOXES AND STATION MASTER'S SLIDE CONTROL FRAMES.

13.3 Periodicity

All interlocking frames, interlocking key boxes and Station Master's Slide Control frames shall be overhauled once in every three years or earlier if necessary.

13.4 Programme of overhauling

13.4.1 The Divisional Signal and Telecommunication Engineer shall draw out a programme of overhauling of interlocking frames, interlocking key boxes and Station Master's slide control frames on the Division on a monthly basis spread preferably over the first 9 months of a calendar year. Any overhauling work that may fall into arrears due to unforeseen circumstances shall be completed during the remaining three months.

13.4.2 The programme shall indicate:

(a) Particulars of Interlocking Frames, Interlocking Key Boxes and Station Master's slide control frames to be overhauled month by month;

(b) Dates of last overhauling.

13.4.3 A Copy of the programme shall be supplied to each Supervisory SSE/SE/JE (Signal) who has to carry out the overhauling accordingly.

13.5 Requirement of materials for overhauling

The Supervisory SE/JE (Signal) shall check before undertaking the work that the material needed for overhauling of interlocking frames, interlocking key boxes and Station Master's slide control frames is available. If not, he shall requisition the same sufficiently in advance so that it is available for the work in time.

13.6 Interlocking Frame

13.6.1 Instructions for working of Traffic during overhauling

When a lever frame, Station Master's control frame or interlocked key box or any other interlocking frame is being overhauled, the station shall be worked in accordance with special instructions issued by each Railway to ensure full compliance with G.R.3.38 and 3.39 and the Station Master shall be responsible for ensuring that all the facing points over which the train will pass, are correctly set, clamped and padlocked and that all trailing points over which the train will pass are correctly set before taking 'OFF' signals. The manner in which Station Master will ensure this shall be clearly laid down. Detailed temporary working instructions shall be prepared for every station by the Divisional Safety Officer for each phase of the work in consultation with concerned Divisional Signal and Telecommunication Engineer and supplied to the station before overhauling is commenced.

13.6.2 A notification showing the date and time when the overhauling work would be taken in hand, its probable duration and instructions for the station Master to issue Caution Order to drivers and for Loco Foreman to advise drivers to observe the temporary speed restriction shall be issued jointly by the Divisional Signal & Telecommunication Engineer and the Divisional Safety Officer.

13.6.3 For the portion of the yard, which is controlled by the Cabin to be overhauled:-

(a) Before undertaking overhauling work wherever required, suitable communication facilities shall be provided.

(b) The Driver shall be issued a Caution order at the last stopping station instructing him of the speed restriction of 15 Km/h at the station where overhauling of interlocking frame is in progress.

(c) Special instructions for reception/dispatch of trains and shunting operations, if any, should be drawn keeping in view GR & SR 15.09 (2) and annexed to the notification referred to in 13.6.2.

(d) Distant/warner signal and main home signal proceed aspect shall be made in- operative. Distant/warner signal shall be kept at 'ON' position.

(e) Wherever work is required to be done during night hours, adequate lighting arrangements shall be provided.

(f) Section of the track, on which caution is to be imposed, must be specified.

13.6.4 Only after the Station Master on duty has assured himself that the line has been correctly set and facing points locked for the required movement, he may permit the signals to be taken 'OFF' for the reception or dispatch of a train.

13.6.5 Disconnection Memo on Form No. S&T/DN (Annexure-2, Chapter XI) shall be given by the SSE/SE/JE (Signal) incharge to the Station Master on duty and his signature shall be obtained before starting the work and reconnection memo shall be given after the work is completed.

13.6.6 The issue of caution orders and the imposition of speed restriction of 15KMPH shall remain in force until interlocking frame has been tested by the authorised official and normal working is restored.

13.7 Detailed Instructions for Overhauling

13.7.1 All interlocking frames shall be overhauled under the personal supervision of the SSE/SE/JE (Signal) incharge.

13.7.2 Before taking up the overhauling of a lever frame, the SSE/SE/JE (Signal) incharge shall examine the lever frame and collect the necessary materials to carry out repairs/rectify deficiencies noticed.

13.7.3 Quadrants, Quadrant supports, Levers, Lever shoes, Locking Boxes, Locking Box supports and Holding down bolts shall be examined to see that they are rigidly fixed and properly secured. The levers shall be aligned in straight line in case any misalignment exists. It shall be ensured that all the parts of the Lever Frame including the spare levers and their tappets are intact. It shall also be ensured that proper padlocking and sealing facility exists.

13.7.4 All notches in tappets, locks and the lock rivets shall be examined to ensure that they have not become unduly worn or slack. False (spare) notches in tappets shall be filled up or the tappets replaced.

13.7.5 All interlocking bars shall be examined to ensure that they are rigid, truly straight and not twisted or buckled. Spare holes in interlocking bars shall be filled up.

13.7.6 All tappets and connecting link pins shall be examined to see that they are not unduly worn out and do not permit excessive lost motion.

13.7.7 All worn out/cracked parts must be replaced wherever necessary.

13.7.8 The inside of the locking box as also the bars, the tappets and the locks shall be thoroughly cleaned with a stiff brush and kerosene. Afterwards, they shall be polished with graphite mixed with thin oil and finally dusted with graphite.

13.7.9 Each interlocking bar shall be tested before refitting to ensure that the locking provided through it is correct and the lost motion of the locked levers or their catch handles is within the permissible limit, i.e. the lever block cannot be moved more than 12mm over the lever quadrant in the case of locking operated directly by the lever. In case of catch handle operated locking, it shall not be possible to raise the catch handle block more than 10mm. Defects, if any, shall be rectified.

13.7.10 Locking shall be refitted carefully. Before replacing the covers, the locking shall be again powdered with graphite. Thin mineral oil shall be used for lubrication when graphite is found unsuitable owing to climatic conditions.

13.7.11 It shall be ensured that waste cotton pieces or any other foreign materials are not left inside the locking boxes.

13.7.12 Before replacing the covers, the locking shall be carefully checked with the approved locking diagram.

13.8 Resumption of normal working

13.8.1 It will be personal responsibility of the Supervisory SSE/SE/JE (Signal) to test all interlocking frames up to 20 working levers after completion of overhauling and to introduce normal working. As regards interlocking frames with 20 to 30 working levers, normal working can be introduced after completion of overhauling and testing of interlocking by the Supervisory SSE/ SE/JE (Signal). The Divisional/ District/Assistant Signal & Telecommunication Engineer must, however test the locking as soon as possible after normal working has been resumed by the Supervisory SSE/SE/JE (Signal).

13.8.2 When the lever frame to be overhauled is more than 20 working levers, as soon as the overhauling work has been completed, it will be the personal responsibility of the Supervisory SSE/SE/JE (Signal) incharge to intimate the Signal Officer concerned that the interlocking frame is ready for his test.

13.8.3 In regard to interlocking frames with more than 30 working levers, it will be the persona! responsibility of the Signal Officer concerned to test all such interlocking frames after completion of overhauling and to introduce normal working.

13.8.4 The testing referred to in para 13.8.1 to 13.8.3 shall be carried out as per approved locking table.

13.8.5 The Divisional/Assistant Signal & Telecommunication Engineer must keep in close touch with the progress of the overhauling work and see that the duration of the work is reduced to what is actually necessary to avoid undue continuance of the restrictions imposed on the traffic working.

13.9 Overhauling of Interlocking Key Boxes

13.9.1 Interlocking Key Boxes must be overhauled under the personal supervision of the SSE/SE/JE (Signal) incharge.

13.9.2 Disconnection Memo on Form S&T/DN (Annexure-2, Chapter XI) shall be issued by the SSE/ SE/JE (Signal) to the Station Master on duty and his signature obtained before starting and reconnection memo issued after completion of the overhauling work.

13.9.3 The responsibility for the safe custody of the interlocking keys released from the interlocking key box as long as the locking is disconnected shall rest with the SSE/SE/JE (Signal) in-charge.

13.10 Overhauling of Station Master's Slide Control Frame

13.10.1 Station Master's Slide Control Frames shall be overhauled under the personal supervision of the SSE/SE/JE (Signal) incharge.

13.10.2 Instructions for working of Traffic during overhauling as laid down in paras 13.6.1 and 13.6.2 shall be applicable during overhauling of Station Master's Slide Control Frames.

13.10.3 The Supervisory SSE/SE/JE (Signal) incharge shall issue disconnection memo on Form S&T/DN Annexure -2 (Chapter XI) to the Station Master on duty and his signature obtained before starting and reconnection memo issued after completion of overhauling work. The following precautions should also be taken by SM on duty to ensure the safety of the train movements.

(a) The Cabin man on duty should be instructed to see that no signals are taken 'OFF' by him unless permitted by the Station Master on duty.

(b) It should be ensured that no electric slot or key is transmitted in an unauthorised manner and that no conflicting slot or key is transmitted.

13.11 Certificate of Overhauling

Locking overhauling certificates on Form S&T/LO Annexure-8 for all interlocking frames, interlocking key boxes and Station Master's slide control frames shall be promptly submitted by the SSE/SE/JE (Signal) to the Divisional Signal & Telecommunication Engineer, in duplicate. The Divisional Signal and Telecommunication Engineer shall, after necessary scrutiny forward a consolidated statement of the overhauling carried out every quarter along with one copy of the Certificate to the Chief Signal & Telecommunication Engineer for his record.

SECTION 'B' - TESTING OF INTERLOCKING FRAMES, INTERLOCKING KEY BOXES AND STATION MASTER'S SLIDE CONTROL FRAMES.

13.12 Periodicity

13.12.1 Locking of interlocking frames, interlocking key boxes and Station Master's slide control frames shall be tested once in a year or earlier if required.

13.12.2 Locking shall also be tested before opening a new installation, after every addition and alteration and immediately after overhauling.

13.13 Programme of Testing

The testing of interlocking frames, interlocking key boxes and Station Master's slide control frames shall be done in a programmed basis on the same lines as laid down in Section 'A' for overhauling. The testing programme shall be arranged as follows:-

First at the time of overhauling, second a year later and third 2 years after overhauling. At the  end of the third year, a test should be carried out separately only if overhauling is not proposed to be done within two months of the date on which periodical testing is due.

13.14 Essential requirements of Locking to be tested

13.14.1 It is essential that the interlocking of all signals with the points is so effected as to ensure the following conditions :-

(a) It shall not be possible to take 'OFF' a running signal until all points on the running line are correctly set and the facing points locked, all points giving access to the running lines from interlocked siding and goods lines are set against the running lines and interlocked level crossing gates on the routes including overlap are closed and locked across the road way. A signal lever when pulled shall lock or back lock as necessary the levers operating the points and gate locks referred to above.

(b) It shall not be possible to take 'OFF' conflicting signals at the same time.

(c) When signals are at 'ON', all points, which would be locked by the taking 'OFF' of such signals, shall be free.

(d) It shall not be possible to take 'OFF' a Warner Signal until all the relative Stop Signals in advance have first been taken 'OFF' and when 'OFF' it must back lock such signals.

(e) It shall not be possible to take 'OFF' main home signal to proceed aspect unless all advance signals like advanced starter, intermediate starter and mainline starter are taken 'OFF' to proceed aspect.

13.14.2 The locking in the frame shall correspond with that shown in the approved Interlocking Table.

13.14.3 The Locking shall be strong, durable and accurate and it should not be possible -

(a) for any mechanical lock to enter a notch other than that for which it is intended;

(b) to force the locking.

13.14.4 The locking in the lever frame shall act on the commencement of the movement of the lever in the case of a direct type lever frame. In the case of a catch handle type of lever frame, the locking shall act on the commencement of the movement of the catch handle.

13.14.5 The release locking shall not be effected before the completion of the movement of lever and releasing the catch handle in the case of catch handle type lever frame.

13.14.6 Lever collars and slide collars shall be tested so that it is not possible to operate a lever or slide with a collar placed on it.

13.15 Methods of testing

There are two methods of testing the locking :-

(i) against the Interlocking Table, and

(ii) against the signalling Plan.

13.16 Testing by the Supervisory SSE/SE/JE (Signal) :-

The supervisory SSE/SE/JE (Signal) shall test locking against the interlocking table and do spot checks from the Signalling Plan.

13.17 Testing by the Divisional/Assistant Signal and Telecommunication Engineer

Divisional Signal & Telecommunication Engineer/Assistant signal & Telecommunication Engineer shall test locking against the interlocking table as well as make spot checks from the Signalling Plan.

13.18 Instructions for testing

13.18.1 All levers shall be placed in their normal position before testing is started. When testing against the interlocking table, levers shall ordinarily be tested consecutively beginning from lever number-1.

13.18.2 In each case where a lever is released by a combination of other levers, it is necessary to have all the levers of the group pulled over to test the back locks, then to put back each lever separately, leaving the other levers pulled over, to test each individual lock.

13.18.3 Some examples of testing locking are as follows -

A. Warner Signal

(i) Try the Warner lever. It should be locked.

(ii) Pull over the relative Loop Homes and Outer Levers and also Loop starters if worked from the same cabin. Try the Warner lever again, it should be locked.

(iii) Pull over the relative Main Home and Outer levers and try the Warner lever again. It should be locked.

(iv) Pull over the Main line Starter lever and once more try the Warner lever. It should be free if there is no other running signal in advance of the Starter signal.

(v) After pulling the Warner lever, see if the Outer, the Home and the Starter signal levers are back locked.

(vi) Replace the Warner, the Outer and the Home signal levers, but leave the starter lever pulled over. Try again to pull the Warner lever. The Warner lever should be locked.

B. Stop Signal

(i) Set up each route separately, and if the stop signal is released by another signal (e.g., the Outer by the Home), prove that the releasing and back locking is correct as in the case of Warner signal levers.

(ii) See that all conflicting point and signal levers, both in advance and in rear of the signal under test, are locked.

(iii) Replace the signal lever under test and pull over each conflicting point lever or combination of conflicting point levers in the route separately and see if the signal lever is locked.

(iv) Try each conflicting signal with the signal lever under test in the normal position, pulling such levers as required releasing each conflicting signal.

(v) Points in rear of the signal under test should be tried both in the normal and reverse positions with the signal lever reversed to see if the both ways locking is correct. The extent of this both ways locking in rear of each signal varies according to local condition.

C. Junction Signal Test

In Figure 1, when lever No.2 is tested, it is not sufficient to pull 3 and try if 4 is locked normal because 3 locks 4 both ways. The methods of testing where the facing points stand normally unlocked, should be as follows :-

(i) Try 1 and 2. Both should be locked.

(ii) Pull 3 and try 1, 2 and 4.2 and 4 should be locked and 1 free.

(iii) Pull 1 and see that 3 is back locked.

(iv) Replace all levers and pull 4 and 3.1 should be locked, 4 locked in reverse and 2 free.

(v) Pull 2 and see that 3 is back locked.

D. Point Locking

The locking between point levers is tested on the same principles as the locking between signal levers, care being taken that each point lever is free to be tested by pulling the releasing levers, if any, and also that points are not being held by facing point locks.

E. Special Locking

Figure 2 is an example of special locking, where 1 is released by 3 when 2 is normal. The method should be as follows :-

(i) Try 1,1 should be locked,

(ii) Pull 2 and try 1,1 should be free,

(iii) Pull 1,3 should be locked and 2 backlocked.

(iv) Replace all levers. Pull 3 and try 1,1 should be free,

(v) Pull 1,2 should be locked and 3 backlocked.

In each case, where a lever is released by a special combination, as in Fig.3, where 1 is released by 4 with 2 and 3 normal, each part of the combination must be tested on the same principle as before. Either 2 reverse or 3 reverse must "break-down" the release on 1 by 4.

F. Reciprocal Locks and Checking

As each lock is tested, its reciprocal should, whenever possible, be tested at the same time. As and when they are dealt with, the figures must be ticked off on the interlocking table so that no lock is missed.

G. Locked Levers

While testing a locked lever, a steady pressure should be applied so as to ensure that it is not free before the releasing lever has completed its travel. This will prove that there are no conflicting notches.

13.19 Test Charts

Test Charts showing the manipulation of various levers to check each locking as detailed in para 13.18.3 should preferably be prepared to facilitate testing of large interlocking frames.

13.20 Lost Motion Test

When a lever or catch handle which should be locked can be moved more than the allowance stipulated in para 13.7.9 it should be considered as having too much lost motion, which must be removed.

13.21 Certificate of testing locking

Certificate of Testing locking on Form S&T/LT (Annexure-9) for all interlocking frames, interlocking Key Boxes and Station Master's slide control frames shall be promptly submitted by the SSE/SE/JE (Signal) to the Divisional Signal & Telecommunication Engineer in duplicate. The Divisional Signal and Telecommunication Engineer shall, after necessary scrutiny, forward a consolidated statement along with a copy of the certificate to the Chief Signal and Telecommunication Engineer for his record.

SECTION 'C' - RECORDS

13.22 Records of testing and overhauling

Record of testing and overhauling of interlocking frames, interlocking key boxes and Station Master's slide control frames shall be maintained as follows :-

(a) At individual stations : In the Signal incidences and Inspection register.

(b) With the SSE/SE/JE (Signal): In a separate Register, a separate page shall be used for each interlocking frame, interlocking key box and Station Master's slide control frame.

(c) With the Divisional Signal & Telecommunication Engineer and the Chief Signal & Telecommunication Engineer: On cards. One card shall be used for each interlocking frame, interlocking key box and Station Master's slide control frame. These cards shall be suitably filled to indicate -

(i) Testing or overhauling due "current period".

(ii) Testing or overhauling "over -due".

(iii) Testing or overhauling "done during the period".

(iv) Testing or overhauling "done during previous period and not requiring immediate attention".

(d) A site verified copy of approved locking table and locking diagram, which was basis for testing on completion of overhauling shall each be maintained with the SSE/SE/JE (signal) and the Divisional Office.

13.23 Date of last overhauling and testing

Date of last overhauling and testing shall be painted on the lever frames, interlocking key boxes and Station Master's slide control frames.

SECTION 'D' - TESTING AND OVERHAULING OF ELECTROMECHANICAL INSTALLATIONS

13.24 Mechanical Locking

13.24.1 Instructions contained in the preceding paragraphs for the installation, maintenance, overhauling and testing of locking of mechanical interlocking frames shall also apply to electromechanical installations with mechanical locking frames wherever relevant.

13.24.2 The mechanical locking of interlocking frames shall be tested for lost motion, as per para 13.7.9 and lost motion, when in excess of the prescribed limits, shall be removed.

13.25 Electrical Locking

13.25.1 In electromechanical installations electric lever locks, key transmitters, circuit controllers etc shall be provided as per approved plan.

13.25.2 Diagram of electrical circuits for each such gears shall be prepared and shall show all the necessary controls which shall be required to release a particular lever.

13.25.3 Where lever locks have been provided in the mechanical lever frames for controlling operation of Electric Point Machine, Electric Signal Machine or for route holding etc the functioning of the same shall be tested.

i) Points Lever: - In points lever ABDE locks are provided for Track & Indication locking. Lever shall be tested to ensure that the lever lock is energised and the lever is free to be operated in A/E position only when the controlling tracks are clear. The lever shall again be locked in D position when the point is being operated from normal to reverse and lever shall be free only when the points has operated fully and locked and detected in reverse position. Similarly, while operating the lever from reverse to normal the lever shall be first locked in E position to ensure track locking and subsequently will be held at B position for point operation. The lever lock shall not energies at B position unless the points have operated, set, locked and detected in normal position.

ii) Signal Lever: - While pulling the signal lever from normal to reverse the lever shall be locked in A position and will be free only when route for the reception of the train has been correctly set, all facing points locked and all the controlling tracks are clear i.e. all conditions are fulfilled for taking 'OFF' the signal. While putting back the lever from reverse to normal position the lever shall be locked at B position and will be free only when the intended movement is completed and it is free from back locking as well as approach locking where provided. Normal indication locking must also be effective in B position in case of semaphore signal.

13.26 Testing and overhauling of Electrical Locking

13.26.1 Mechanical interlocking frames provided with electrical signalling equipment shall be tested and overhauled as per requirements contained in Chapter XIX.

13.26.2 The testing of electrical locking shall be carried out in accordance with the approved release circuit of each lever as shown on the approved diagram of electrical circuits.

13.26.3 For testing the electrical locking provided on a lever, the other levers required to release that lever shall be pulled and it must be ensured that the lever is free to be pulled mechanically.

13.26.4 All the conditions for the release of the electrical lock of the lever under test shall be set up. The lever shall now be pulled from normal to reverse for testing of A&D locks and reverse to normal for E&B locks and proper functioning of the lever locks checked.

13.26.5 A test lamp/voltmeter shall now be connected on the electrical lock of the lever under test. The lever shall now be pulled from normal to reverse and vice versa. The test lamp should lit up at lock positions. The lever shall be held at these positions one after the other and all the lock release conditions shall be broken one by one. It shall be ensured that feed to the lever lock is disconnected each time. While doing this test, care shall be taken to test each circuit individually one after the other duly isolating other parallel circuits.

13.27 Testing of other electrical equipments

13.27.1 Instructions contained in section 'E' for testing of electrical signalling installations shall also apply to electromechanical installations wherever relevant.

13.27.2 All electrical equipments such as electric lever locks, circuit controllers etc., as well as wiring shall be examined and tested for insulation. The insulation must not be less than ten Mega Ohm. Defective equipments shall be replaced.

13.27.3 Moving parts of circuit controllers, their mechanical connections and contact makers shall be checked. Repairs and replacements should be carried out wherever necessary.

13.28 Date of last overhauling and testing

Date of last overhauling and testing should be painted on the interlocking frame.

13.29 Certificate of overhauling

Locking overhauling certificate on Form S&T/LO Annexure -8 (para 13.11) for all mechanical interlocking frames shall be promptly submitted by the SE/JE (Signal) to the Divisional Signal & Telecommunication Engineer, who shall after necessary scrutiny forward a consolidated certificate to the Chief Signal & Telecommunication Engineer.

SECTION 'E' - TESTING OF ELECTRICAL SIGNALLING CIRCUITS

13.30 General

The checking and testing of electrical signalling installations may be divided into five different groups as detailed below:

13.30.1 Physical inspection of the installation.

13.30.2 Checking of the wiring and cables.

13.30.3 Testing of the individual circuits.

13.30.4 Testing of individual apparatus.

13.30.5 System testing of the installation.

13.31 Test Procedure

Systematic methods such as marking on locking/selection tables and suitably and clearly marking on the circuit diagrams while checking the circuits and equipment should be adopted to ensure that all circuits have been completely checked.

13.32 Suitable proforma should be devised for recording the tests of electrical equipment before testing of the installation is taken up to ensure availability of records of the tests and their analysis.

13.33 Testing Instruments

Suitable instruments should be used in the testing of electrical signalling circuits. Calibration of these instruments should be checked periodically.

13.34 Physical inspection of the installation

13.34.1 It shall be checked that the work has been carried out in accordance with the approved plans and that equipment is of proper type and is in good condition.

13.34.2 The following aspects shall be checked during the physical inspection:

a) The signals, location boxes and other out-door equipment are as per approved plans and are in good condition. Arrangements for proper ventilation, where provided, are not choked.

b) Each location contains all the apparatus required as per approved plans, the apparatus is of approved type and that the power supply equipment, batteries, fuses, etc., are installed according to the approved plan and specification.

c) The location of insulation joint, jumper wiring, traction bonding in electrified areas, point machines, switch locks and other apparatus is as per approved plans and their condition is satisfactory.

d) The electrolyte, inter-connections between cells, cell voltage etc., are in required condition as per relevant specifications or instructions.

e) Each wire is tagged or marked where feasible so that it can be identified at each end and the nomenclature on the tag corresponds to that on the wiring diagram. The tags or other sleeves of identification shall be of insulating material.

f) The number of wires terminated on each terminal or relay terminal boards or other devices are counted and tallied with the number of wires shown in the wiring diagrams.

g) All connections on terminals and binding posts are properly secured,

h) The lightning arrestors are properly connected and earthed as per plan.

i) Detailed specifications & instructions for inspection and testing of different types of equipment as applicable to them should be available.

j) All other equipment such as lever frames, cable sheaths, signal screens, location huts, etc., in A.C. electrified areas are properly earthed as per requirements contained in Chapter XXII.

k) No equipment including relays are due for overhauling.

13.35 Checking of the wiring

13.35.1 Wiring shall be checked to ensure that it has been carried out as per approved wiring diagram. Point to point testing shall be carried out before plugging in the relays. Wires shall be tested one by one for continuity and insulation.

13.35.2 Prior to conducting continuity and insulation test, contact occupancy test must be carried out for each relay as per the contact analysis available. The number of contacts allotted must tally.

13.35.3 During the course of continuity testing, wire count test shall also be done simultaneously to verify the number of wires actually available on each contact.

13.35.4 All cables shall be tested in accordance with the instructions given in Chapter XV.

13.36 Test of individual circuits

13.36.1 It shall be checked that each individual circuit is actually controlled by the proper contacts of the relays or other devices as per wiring diagram.

13.36.2 Where feed to a particular device is controlled through two or more paths in parallel, the check of each path must be carried out separately.

13.36.3 Cases of intermittent or continuous extraneous feed of even small magnitude or wrong operation of any relay observed shall be investigated thoroughly and remedial action taken to rectify the fault.

13.36.4 Once the indoor wiring works are completed before conducting the system testing as detailed in para 13.38, simulation test shall be conducted. This will ensure the correctness of indoor system, complete. System testing shall be carried out after all the field functions are connected to the relay room.

13.37 Testing of individual apparatus

Testing shall be done as per relevant paras of Chapter XIX in accordance with specification & instructions applicable to each individual apparatus.

13.38 System Testing of Installation

13.38.1 After the tests mentioned in previous paras have been carried out, the electrical installation shall be subject to the detailed operational/system tests.

13.38.2 These tests shall be planned carefully. Requisite number of staff considered essential for carrying out such tests shall be selected and deputed to concerned locations. They should be equipped with requisite tools, meters, portable telephones and/or walkie talkie sets so that they are in contact with the official in charge of testing and other testing parties and take such action as directed.

13.38.3 These tests shall be carried out against approved Selection Table/Control Table/Route Chart and Signalling Plan.

13.38.4 Complete tests shall be carried out against approved Selection Table/Control Table/Route Chart. Checks against signalling plans for main signal routes and a few spot checks of the remaining routes shall also be carried out.

13.38.5 Following guide lines are laid down for carrying out system tests:-

(a) Signal Control Circuits

Each route shall be set individually by operating control lever or switch (es) and/or button (s) as the case may be. After checking that the signal for this particular route has been cleared, each track circuit controlling the signal shall be shunted individually to check that the signal goes back to danger. Similar tests shall again be made by de-energizing point detection relays and other relays controlling this route. Each such relay will be de-energized individually and it shall be checked that the signal goes back to danger.

(b) Approach Locking

Each route shall be set up individually. After ensuring that the signal for this particular route has been cleared, each track circuit controlling the approach locking shall be de-energised in turn. The signal shall be put back to 'ON'. Efforts shall be made to alter the route under test and to set up conflicting route. It shall be checked that it is not possible to cancel the route set up and/or to set up a conflicting route and/or to individually operate any point in the route under test. This locking shall be effective till the set route is cancelled and the time release circuit has operated provided the track beyond the signal is not occupied.

(c) Route Release

(i) Tests shall be carried out to ensure that once a signal is cleared for a particular route, position of none of the points in the route can be changed when track circuit immediately in advance of the signal is de-energised.

(ii) Where sectional route release is provided, it shall be ensured that a sub route does not release only by picking up of the concerned track relay (s) but the same should be released only after the next track circuit has also dropped and picked up.

(iii) Where sectional route release is not provided tests shall be made to ensure that the entire route remains locked when any of the track circuits beyond the signal up to the track circuit controlling the last point is de-energised.

(iv) In cases where the route is controlled by single track circuit the route shall be released after prescribed time delay to be effective after the concerned track circuit has been occupied and cleared by the train.

(d) Time Release

Time release, where provided, shall be tested to ensure that it will be possible to alter the route or set up a conflicting route or change the position of the points in the route only after the signal is put back to 'ON' and the prescribed time interval has lapsed. Similar tests shall be carried out for overlap release, where time release is provided for releasing the overlap after the occupation of the berthing track.

(e) Dead Approach Locking

Where dead approach locking is provided, the same test procedure as in (b) will be adopted except that there is no controlling track circuit to be de- energised. After the signal has been taken 'OFF', the approach locking shall be effective till the signal is put back to 'ON' and time release circuit has operated.

(f) Signal Indication Circuits

Indication of 'ON' aspect of all signals shall be checked for its correspondence with aspect displayed at site. Each signal shall then be cleared after setting its route and the indication of each aspect shall be checked for its correspondence with the aspect displayed at the site. This test shall be carried out for each signal as well as for direction type route indicator where provided. In the case of later, it shall also be ensured that the indication relay is not energised and the indication does not appear until the minimum number of lamps as required are actually lit.

(g) Point Controlling Circuits

Each point shall be set to reverse position by operating the controlling lever/switch/button. After the point has been fully reversed, each track circuit controlling the point shall be individually shunted in turn and operation of points to normal position shall be attempted. It shall not be possible to operate the point under these conditions. These tests shall be repeated with the point set in normal position, attempt being made to operate it to the reverse position.

With the obstruction in the points, the point shall be operated from normal to reverse and reverse to normal and it shall be checked that the over-load relay where provided gets energised and the feed to the motor is cut off immediately. Where over load relay is not provided, the feed to the motor shall be cut off after the lapse of a prescribed time.

The out of correspondence test shall be carried out by opening cut out contact of one end of point machine and the point lever/knob/button operated. The other end of the point may operate but the point indication relay shall not energise.

(h) Point Indication Circuit

The point shall be operated from normal to reverse and reverse to normal and the position of point detection relay as well as the indication of the point in the cabin/panel shall be checked for correspondence with the position of the points at site. It shall also be checked that with the obstruction in the point, the detection relay is de-energised and both normal and reverse point indication in the cabin/panel are extinguished in case of electromechanical signal and flash in case of PI /RRI installations.

The operation of the detection relay to the correct position as well as its de-energisation should be checked by making and breaking the relevant point detector contacts at site.

(i) Crank handle interlocking

It shall be checked that when the crank handle is removed from its normal position in Electric Key Transmitter/other approved Relay interlocking arrangement, the signals reading over the concerned route/zone cannot be taken 'OFF' nor the points could be operated from the cabin/ panel. It shall also be checked that when the signal reading over the concerned route/zone is taken 'OFF', the crank handle cannot be released from its normal position in Electric Key Transmitter/other approved Relay interlocking arrangement.

(j) Testing of Track Circuits

Testing and inspection shall be done as per Chapter XVII.

13.39 Typical testing Procedure for Panel Interlocking/Route Relay Interlocking Installations

Typical testing procedure for panel interlocking /Route Relay interlocking installations are given below. It shall be ensured that the interlocking system conforms to the approved relay interlocking specification.

13.39.1 Panel Interlocking installation:

(i) Point Locking

Operate point No. 2 to reverse position and clear the signal route No. 2WBI by operating signal switch/button. Operate point knob 2 to normal. The point should remain locked. Restore the point knob to reverse. De-energise 2RWKR. Signal 2WBI shall go to 'ON'. Restore the signal switch/button to normal. When point No. 2 is free, shunt the track 2T. Turn the point knob 2 from reverse to normal. The point should remain locked.

(ii) Approach locking

Take 'OFF signal for route No. 2WBI by setting the points in required position. Normalize the signal switch with A2WT clear. The signal assumes 'ON' position. Try to alter the route, it should be free.

Again take 'OFF' signal for route No. 2WBI. Shunt the approach Track A2WT. Normalize the signal switch/button. Try to alter the route. Route should be held till the route is cancelled and 120 sees, time delay has lapsed.

(iii) Interlocking of signals

Clear the signal route 2WBI after setting the route. Try to clear the signal 4EB by operating the relevant switch/button. Signal 4EB should remain in 'ON' position and signal 2W should continue to display 'OFF' aspect. Similar tests shall be carried out for signal 2E also.

(iv) Track Circuit Controls

Clear the signal route 2WBI again. Shunt the track 2WT. Signal should go to 'ON'. Remove the shunt, the signal should not re-clear. Normalize route and re-clear again. Shunt A2ET and other controlling track circuits one by one. Signal should go to 'ON' in all cases. Remove the shunt. Normalize the route.

(v) Back locking

(a) Clear the signal 2W for route 2 WBI again. Shunt the track 2WT. The signal should go to 'ON'. Normalize the signal switch/button. The route should be held. Shunt and clear all the back locking tracks as per selection table in sequence. The route shall be released by sequential proving of tracks as per the provisions of para 4.3.3 of Relay interlocking specification IRS: S 36-87.

(b) Clear the signal route 2WBI again and de-energize the L-xing gate control relay. The signal should go to 'ON'. Re-energize the relay, the signal should assume 'OFF' aspect.

13.40 Periodicity of Tests

13.40.1 All the tests indicated in Para 13.30 shall be conducted at the time of new installation or making any alteration to the existing installations.

13.40.2 Periodical Testing

13.40.2.1 In a working installation, the following periodical tests shall be done: -

(i) Physical inspection as per Para 13.34 once in a year or earlier to the extent feasible;

(ii) System tests as per Para 13.38 once in three years or earlier;

(iii) Insulation tests on Cables as per Para 15.23.1.

(iv) Test of individual apparatus in accordance with specifications and instructions applicable for each apparatus as stipulated in Chapter XIX

13.40.2.2 It will be personal responsibility of supervisory SSE/SE/JE (Signal) to test all Electrical signalling circuits of relay interlocking up to 20 routes.

13.40.2.3 It will be personal responsibility of Signal Officer concerned to test all electrical signalling circuits of relay interlocking with more than 20 routes.

13.41 Precautions during Testing

Following precautions in addition to what is stipulated in para 11.4 shall be taken during testing and checking so that -

(a) No signal taken 'OFF' for a train movement is thrown to 'ON' in the face of the train.

(b) No signal which will create a conflicting or unsafe movement is taken 'OFF

(c) No point and isolation in a route set for a train movement is disturbed.

(d) No track relay of an occupied track circuit is energised.

(e) No voltage higher than permissible voltage is applied to the equipment.

(f) There should be no risk of electric shock to testing or operating personnel.

Form No. S&T/LO
Annexure 8
Para 13.11

....................RAILWAY
SIGNAL AND TELECOMMUNICATION DEPARTMENT CERTIFICATE OF OVERHAULING INTERLOCKING FRAMES

No........................

To

The Divisional Signal and Telecommunication Engineer,                                                               ......................................Division

This is to certify that I have personally supervised the overhauling of the interlocking frames/ Interlocking key boxes/Station Master's slide control frames at the station/cabins on my section shown below, and that they have been thoroughly examined and cleaned, also repaired or refitted where necessary and all parts are in good working order. The mechanical locking is in accordance with the approved interlocking charts and interlocking tables.

Dated:

Signature.... ............

Designation...............

Station....................

Form No. S&T/LT
Annexure 9
Para 13.21

...........................RAILWAY

SIGNAL AND TELECOMMUNICATION DEPARTMENT CERTIFICATE OF TESTING LOCKING forthe month ending.....................20..

No..............

To,

The Divisional Signal & Telecommunication Engineer,

......................................Division

This is to certify that I have personally tested the interlocking frames, interlocking key boxes and Station Master's slide control frames at the stations on my section shown below and that they are in good working order and that the mechanical locking/electrical locking is in accordance with the approved interlocking tables.

Dated:

Signature.... ...........

Designation..............

Station...................