CHAPTER -XIX

DETAILED INSTRUCTIONS FOR INSTALLATION AND MAINTENANCE OF ELECTRICAL SIGNALLING EQUIPMENT

SECTION 'A' - GENERAL INSTRUCTIONS FOR PROPER USE OF TOOLS

19.1 All staff engaged in the installation and maintenance of electrical signalling equipment shall be in possession of proper tools. List of specific tools shall be circulated by CSTE.

19.2 While using metal tools like screwdrivers, nose pliers, cutting pliers, etc. near the working apparatus, care shall be taken to avoid short circuiting and consequent blowing out of the fuse.

19.3 All staff shall possess adequate number of appropriate insulated tools like rubber gloves, pliers, screw drivers, etc. A rubber floor mat may be used for standing while attending to circuits carrying more than 110-Volt except in outdoor locations. Signal maintainer shall possess a competency certificate for working on more than 110V AC circuits.

19.4 Soldering connections

19.4.1 Staff working in the installation and maintenance of electrical equipment shall be conversant in use of soldering iron/gun for making good soldering joints.

19.4.2 Care shall be exercised to avoid dropping of particles of solder and clippings of wire on adjacent terminals and apparatus.

19.4.3 In addition to soldering irons of adequate wattage for the type of work done, the following shall be at hand:

(a) A Small file for dressing the soldering tip;

(b) A fire proof pad for wiping the tip;

(c) A mica sheet of adequate size or a suitable stand for soldering iron

19.4.4 Electrical soldering irons shall be switched off when not in use over extended periods.

19.4.5 While making a soldering joint, the surface shall be thoroughly cleaned, fluxed and tinned.

19.4.6 Use of too much solder shall be avoided to prevent lumpy connection.

19.4.7 Soldering iron shall not be held on the wire connection for too long to avoid damage to insulation.

19.4.8 Imperfect joints are the result of any one of the following causes, which should be avoided,

(a) Soldering iron not sufficiently hot.

(b) Soldering iron held on the connection for insufficient length of time

(c) Unclean terminal or wire.

(d) A solder of improper composition or inferior fluxing agent.

19.4.9 A newly soldered connection shall not be disturbed till the solder has thoroughly cooled.

19.5 Wire Termination

19.5.1 While terminating wires, care shall be taken to bend the wires in clockwise direction.

19.5.2 Wire strippers shall be used for the purpose of stripping off the wire insulation. Cutting pliers shall not be used for the purpose.

19.5.3 Washers and check nuts shall be used whilst fastening.

19.5.4 Not more than two wires shall be terminated on one terminal.

19.5.5 Multi-strand wires shall be terminated on terminal lugs and covered with insulation sleeves.

19.5.6 Wires of cable shall be neatly terminated and properly bunched.

19.5.7 Crimping tools of appropriate design should be used.

SECTION 'B' :- COLOUR LIGHT SIGNALS INSTALLATION

19.6 Type :- Colour Light Signals shall be multi unit of approved type.

19.7 The signal shall have a minimum visibility as indicated in Chapter Vll. Spread light lenses may be used on curvatures and gradients to ensure continuos visibility of signals.

19.8 Location :- The location and spacing of signals shall be in accordance with approved plans. The signal shall be so located that a clear view is available to the driver of an approaching train and is as close to the track as permissible. The height of normal aspect of the signal shall be approximately at 3.65 metre from the rail level. Wherever this is not feasible due to local terrain, height of the signal post may be suitable increased or decreased to get a clear view of the signal. The actual visibility of signal shall be checked by a sighting committee and action to improve the visibility taken on recommendation of the committee before commissioning a new signal.

19.9 Mounting and Fixtures :-

19.9.1 Colour Light Signals may be mounted on a rigid ground post or a signal gantry clear of standard dimensions.

19.9.2 Each signal unit shall be rigidly fixed in position.

19.9.3 Signal posts shall be kept plumb and lead wool packed.

19.9.4 Lead wool packing may be used to close the excess gap from post to signal unit, surface base to post. The cable entry at the signal unit should be provided with wooden plug around the cable to close excess gap to prevent rodent entry.

19.9.5 Signal number plate shall be provided.

19.10 Alignment :- Each signal unit shall be aligned correctly to the required distance and direction by employing the sighting hole along the side of the signal unit and by manipulating the separate horizontal and vertical adjustments.

19.11 Focussing :- Each aspect shall be properly focussed.

19.12 Hoods and Back Screens: - Hoods of adequate size to counteract the effects of sunrays shall be provided. Where required, metallic mesh at suitable spacing shall be provided to protect lenses from outside interference.

19.13 Cables :- Cables shall be used from the point of operation to the location box/signal unit and/ or location box to the signal unit. Cable shall be protected suitably at the entry points of location box and signal post..

19.14 Gaskets and Sealing :- All openings shall be gasketted and cable/wire entrance shall be sealed to make the enclosure water tight, dust-proof and vermin-proof,

19.15 Locking :- The housing shall be kept locked.

SECTION 'C - ELECTRIC SIGNAL MACHINES

19.16 Electric Signal machines shall be Top of Mast' type and shall conform to approved specifications. Suitable anti-theft measures shall be provided.

INSTALLATION

19.17 General :

19.17.1 Electric signal machines shall be installed in accordance with approved plans.

19.17.2 Before installation of the machine, it shall be ensured that-

(a) The signal post is plumb and where necessary has been suitably guyed, especially where fitted on top of mast.

(b) The machine has been properly cleaned, greased and oiled in accordance with the manufacturer's instructions and working freely

(c) A suitable platform has been provided on the signal post for the maintainer to have an easy access to all parts of the machine.

19.17.3 The machine shall be fixed to the post with clamps of suitable size and be prevented from slipping downwards.

19.17.4 Only 'B' type spectacle shall be used for semaphore arm operated through electrical signal machine mounted top of mast, however, 'A' type spectacle may be used for base of mast mounted electric signal machine.

19.17.5 Excessive lowering more than 50� or excessive raising more than 90� shall not be permitted to ensure self-restoration of signal arm when signal is put back to ON.

19.17.6 Gaskets and sealing shall be in accordance with Para 19.14.

19.18 The signal machine shall be worked on cable.

19.19 Testing :- Machine shall be tested in accordance with para 19.115 before being brought into use, and thereafter at such interval as laid down in Chapter XIII.

19.20 Locking :- The housing of the machine shall be locked. Anti-theft arrangements shall be provided where required.

SECTION 'D' - ELECTRICALLY LIT SEMAPHORE SIGNALS

19.21 Electrically lit semaphore signals where provided shall conform to approved drawings and normally be operated from batteries charged from solar panels or alternatively from the battery charger, provided electrical power is available.

19.22 A suitable device of an approved type shall be used to switch off the power supply during day light, where it is so desired.

19.23 Fixing arrangements of signal lamp for electric lighting of signals shall be of approved design. The arrangement for electric lamp should be such that in emergency Kerosene oil lamp can be provided without modification to the fixing arrangement. Focussing arrangements by way of horizontal and vertical adjusting screws similar to Kerosene lit lamps shall be provided.

SECTION 'E' - ELECTRIC SIGNAL REVERSERS

19.24 Type :- Electric Reverser shall be of an post mounting type as per approved design.

19.25 Fixing :- Reverser shall be securely fixed. The signal controlled through the reverser shall return to 'ON' when the control circuit is opened.

19.26 Locking :- Covers must be properly fitted and securely locked.

19.27 Installation :-

19.27.1 Oil level in the dash pot shall be checked to be minimum 35mm from the bottom surface of the sliding cylinder.

19.27.2 Proper fitting of all parts shall be checked by visual inspection.

19.27.3 Manual check lock shall be effective.

19.27.4 Circuit Controller shall be adjusted for �5� for ON proving, 4o�-60� for lowering for OFF proving, 45�-60� for raising for caution/attention proving and 85�-90� for clear aspect proving.

19.27.5 All bolts and nuts to be tightened fully and split pins opened.

SECTION 'F' - ELECTRIC POINT MACHINES

REQUIREMENTS

19.28 Type: - Electric Point Machines of an approved type shall be used.

19.29 Electric Point Machines shall be installed in accordance with approved plans. Ground fittings of approved design shall be used. Ground connections shall be thoroughly checked for any crack or improper welded joint. Normally the machine shall be installed beside the close switch leading to high-speed movements clear of all infringements. Before installation of the machine, it shall be ensured that �

19.29.1 The permanent way Inspector has made all the provisions at the Points as detailed in Para 12.40 of Chapter XII.

19.29.2 The machine has been properly cleaned, greased and oiled in accordance with the manufacturer's instructions and is working freely.

19.29.3 Proper alignment and level of connections is maintained between the machine and the point gears.

19.29.4 The top of sleepers which are to support the point machine are at level and that surrounding ballast is well tamped to prevent sinkage during the passage of train.

19.29.5 The machine shall be so installed that it is clear of all infringements.

19.29.6 Proper drainage shall be provided to avoid water logging near point area.

19.30 Wiring :- Wiring from the point of operation to the location box/apparatus case nearest to the machine shall be in cable. The power cable shall be of appropriate size to keep the voltage drop minimum. The connection between location box/apparatus case and point machine shall be through underground cable adequately protected below track and near point machine, through Gl pipe or equivalent. It shall be tested for insulation and continuity before bringing into operation.

19.30.1 The excess gap around cable entry to the machine shall be plugged to avoid rodent entry.

19.31 Gaskets and sealing :- Electric Point Machine shall be provided with suitable gaskets and wire entrances shall be sealed to make them water tight and dust proof. All the extra openings shall be closed as far as possible.

19.32 Locking :- Electric Point Machine covers shall be locked. The cover provided for insertion of crank handle shall also be locked with separate key providing access only for crank handle and crank handle key.

19.33 Notches in stretcher blades:- Notches/Notch profile of the locking, driving and detection slides should not be tampered/reconditioned. Worn-out slides should be replaced with new ones.

19.34 INITIAL ADJUSTMENT OF POINT MACHINE

19.35 Adjustment of Driving Rod:- The points shall be adjusted by operating the machine first by hand crank. The insertion of hand crank should disconnect the power supply to the machine. When the machine has been fastened down, the throw bar connections shall be set up and the point machine hand cranked to one end of the stroke positioning the locking blades so as to allow the appropriate locking dog to pass through notches. The closed switch shall be adjusted to just in contact with the stock rail. Then the connections shall be tightened further by 2 mm to 3.5 mm to impart a springing action to the tongue rail. The machine should be hand cranked to the opposite end of the stroke and the setting repeated for the other switch.

NOTE: Unless any special instruction are issued by the Railway, adjustment for driving rod and lock rod shall be done for the close switch nearest to the point machine first.

19.36 Adjustment of detector contacts:- The machine shall be hand cranked to the end of the stroke to close the tongue rail. Insert 1.6 mm test piece between stock rail and switch rail at 150 mm from toe of the switch and operate the point. Ensure detector contacts just make. A test gauge of 3.25 mm shall be inserted between the switch rail and stock rail at a distance of 150 mm from the toe of the switch. The detector connection of the closed switch shall be adjusted till the appropriate detector contact are just broken. The same shall be repeated at the other end of the stroke. All the relevant nuts shall be tightened.

NOTE: Where lock slide is provided in the machine, during switch detector adjustment the test shall first be done with fictitious locking. After completing the above test, same test be repeated with machine properly locked.

19.37 Adjustment of friction clutch:- Friction clutch should be so adjusted that slipping current is between one and half times to twice the normal operating current or as specified by the manufacturer. For rotary type point machines no attempt should be made to adjust friction clutch at site. Friction clutch can only be adjusted in authorized Workshop. When difference between normal operating current and operating current under obstruction is less than 0.5A, the clutch requires adjustment. Such machine should be replaced.

19.38 Obstruction Test:- The point driving rod and the lock connections of the machine must be so adjusted that with 5 mm thick test piece obstruction placed between the switch and the stock rail at 150 mm from the toe of the switch:-

i) the point cannot be locked,

ii) the point detector contacts should not assume the position indicating point closure &

iii) Friction clutch should slip.

SECTION 'G' - ELECTRICAL DETECTOR

INSTALLATION

19.39 Electric detector of an approved type shall be used. Normally it shall be installed beside the close switch leading to high-speed movement, clear of all infringements as per approved plan and drawing.

19.40 Detectors shall be mounted either on the left or on the right hand side of a point layout clear of infringements.

19.41 The detectors shall be mounted on extended sleepers or as per any other approved arrangement.

19.42 Contacts shall be adjusted so that they make or break at the same time. Shunt contacts shall be adjusted so that they do not make before the detector contacts break. In AC traction area shunt contact shall not be used. Care shall be exercised to check that the detection contacts flex a little after they are closed.

19.43 All nuts and screws shall be tightened. Check nuts with spring washer shall be provided.

19.44  After installation before connecting the detector slide, the slides shall be pulled by hand to check for free movement. Binding, if any shall be attended to.

19.45 The lock slide shall be pulled and it shall be checked that as soon as the roller is lifted above the slot in the lock slide, the normal or reverse contacts are open and the shunt contacts are made. The electrical detector must be so adjusted that with 3.25 mm thick test piece obstruction placed between the switch and the stock rail at 150 mm from toe of the switch - The electrical detector contacts shall not make.

19.46 To keep the slides in correct position the locating marks on the switch and lock slides shall be made use of.

19.47 Circuit Controller

19.47.1 Installation of circuit controller shall be done in accordance with approved plans on a rigid base as under:

(a) Single wire lever frames:- On under frame in cabin basement & actuated by a connecting rod connected to lever tail

(b) Ground frames:- As per approved plan & actuated by a connecting rod connected to lever.

(c) Double wire lever frame:- Behind the levers, actuated by a connecting rod connected to lever tail.

(d) Signal post:- Using clips & bolts, its arm shall be directly actuated by the signal arm.

19.47.2 Connect connecting rod on circuit controller arm in its normal position to the lever tail/ lever/ signal arm in their normal position as the case may be. It shall be ensured that stroke available from above gears is not adjusted more than the stroke required by circuit controller in its extreme positions.

19.47.3 The contact segment shall be cut clean to required length & edge shall be tapered. While 'fixing, it shall be adjusted in required position & ensured that it does not make in any other position.

19.47.4 Contact segment positions when used with lever.

 

Lever position	Description
N	Full normal position of lever.
A	Normal lock/ Track lock while during movement from Normal to Reverse.
B	Normal indication lock position for point during movement from Reverse to Normal between 'C & 'A' position.
C	Centre position of lever.
D	Reverse indication lock position for point during movement from Normal to Reverse between 'C & 'E' position.
E	Reverse lock/ Track lock during movement from Reverse to Normal.
R	Full reverse position of lever.
Longer contact segments may be used where required. Some typical examples are as under
AB	For Normal lock cum Normal indication locking.
AC	On lock bar/ Signal lever for door lock release on Double line block instrument.
AE	Normal/ Reverse track locking without indication locking.
AR	To feed electric signal reverser.
DE	For Reverse lock cum Reverse indication locking.

Contact segment adjustments, when used for arm proving

SECTION 'H' - RELAYS

REQUIREMENTS

19.48. Type:- Relays of an approved type shall be used.

19.48.1 Line relays of Neutral/ Polar Biased/ Magnetic latch/ Interlocked type rated at 24/60 V DC shall normally be used. Normally plug-in type relays shall be used.

NOTE : 12 V DC shelf type relays shall not be used in new installations, except as mentioned above. Also, effort shall be made to reduce their use in existing installations in phased manner.

Shelf type Polar line relays of approved type, shall only be used in line circuit for block working.

Suitable type of Lamp proving relays for ON & OFF proving shall be used for signal lamps operating on DC or AC to meet with parameters to suit various lamps.

Special line relays of reed type shall be of double tuned filter type.

19.48.2 Track relays shall always be of metal to carbon contact type & normally be of plug in type, unless otherwise specially permitted.

NOTE : The use of Shelf type track relays snail be avoided in future installations. In case power is not available & their use can not be avoided, the length of track circuit shall be decided, taking into account the maximum sectional speed & drop away time of relay ( normally 1200 msec) & its follower repeating line relay (normally 600 msec for shelf type line relay). Also, effort shall be made to reduce their use in existing installations in phased manner.)

In non electrified area, the following relays shall be used:-

9 ohm DC non-AC immunized (shelf type & plug-in type).

4 ohm DC non-AC immunized.

2.25 ohm DC non-AC immunized (Shelf type).

In electrified area, the following relays shall be used:-

9 ohm DC neutral, AC immunized.

9 ohm DC biased, AC immunized.

Double element motor type relay, operating on 83 & one third Hz in AC traction area and 50 Hz in DC traction area shall be used. Vane type relays may continue in use till replacement.

Relays for track circuit provided with coded, pulsed, electronic (audio frequency or high frequency track circuit), shall be of an approved type of track/ line relay or as recommended by manufacturer.

19.48.3 Where magnetic latch relays are used, the circuit shall be so designed so as to prevent undue dropping of the relay due to back emf generated by other relays.

19.48.4 Wiring of 'Q' type relays shall be done through flexible wire preferably.

19.49 Mercury wet contact type relay shall be used for flasher circuits, alternatively, a solid state flasher may be used. If solid state flasher is used, flashing indication on operating panel should be provided for indicating healthy condition of flasher.

19.50 Storage:- Relays shall be kept in reasonable storage condition. It shall be ensured that such a storage place is not in the vicinity of damp or chemically polluted environment.

19.51 Sealing screws of the relays shall be intact.

19.52. Transportation:- Care shall be exercised in transporting the relays from the place of storage to the work site so that the relays do not get damaged.

INSTALLATION

19.53 Location :- It shall be ensured that as far as practicable, the relay room is not located in the vicinity of chemical factory, loco shed or engine ash pits etc. In case it becomes unavoidable, necessary precautions shall be taken so that relays are least affected by the chemical fumes, dust etc. and are provided with dust free environment. Where there is concentration of relays, Air-conditioning shall preferably be provided.

19.54 Where Relays can not be located in the Cabin, they shall be housed in location of approved type which are properly secured.

19.55 Where relays are likely to be subjected to vibrations, they shall be mounted in such a way that the relays are free from shock and can not be tilted.

19.56 It is desirable to provide insulating caps on the terminals of shelf type relay to avoid inadvertent short-circuiting during maintenance.

19.57 When a number of shelf type relays are used, the mounting and arrangement of relay rack shall be such as to facilitate easy maintenance. Suitable anti-tilting arrangement shall be provided wherever shelf type relays are used.

19.58 Relays shall be housed on level surface.

19.59 In 'Q' style relay the code pins configurations for plug in relay shall not be changed by drilling additional holes on plug board to avoid fixing of a wrong relay which may lead to unsafe condition. In Siemen's K-50 relays, the Code pins position on base plate should not be changed and to be retained as fixed by the manufacturer.

19.60 All relay clips shall be checked for proper locking in the base when plugged in. Extreme care shall be exercised while removing the clips from the jacks of the plug-in type relay.

19.61 In all installations, a relay index board shall be provided for locating relays easily.

19.62 Relays involving external circuits shall have cross protection and double cutting. Signal control relays shall preferably be provided with double cutting.

19.63 A contact chart shall be prepared duly showing the contacts used circuit-wise with reference and spare contacts available, wire count for each contact and relay position in the rack.

19.64 Sealing of Plug-in Relays

19.64.1 In case of metal to carbon contact type relays, sealing shall be done at Manufacturer's premises before dispatch and if the seals have to be broken due to any defect noticed, resealing must be done at the workshops.

19.64.2 In case of metal to metal contact type relays, sealing of the cover shall be done by the Section Engineer at site. Whenever seals have to be broken at site for maintenance purposes, the same shall be done by an official not below the rank of Section Engineer.

19.64.3 Line Relays shall be energized at the rated voltage specified in the specification.

19.64.4 Locking screw shall be removed and the hole sealed in case of Shelf type relays.

SECTION M' - STATION MASTER'S SLIDE CONTROL FRAMES

19.65 Type : - Station Master's slide control frame shall be of approved type.

19.66 Fixing :- Station Master's Slide Control frame shall be securely fixed and the fixtures shall be substantial.

19.67 Location :- Station Master's slide control frame shall be suitably located, preferably adjacent to other instruments in the Station Master's office.

19.68 Mechanical Locking :- Mechanical locking of Station Master's Slide Control frame shall be in accordance with approved plan.

19.69 Locking or sealing :- Station Master's slide control frame shall be securely locked and the locking box sealed.

SECTION 'J' - ELECTRIC KEY TRANSMITTER

INSTALLATION

19.70 Type : - Electric key transmitter of an approved type shall be used.

19.71 Fixing :- Electric key transmitters shall be securely fixed vertically. There shall not be any opening giving access to the interior of the key transmitter through which it is possible to operate the mechanism by any irregular means.

19.72 Location :- Electric key transmitters shall be fitted as near as possible to the gear they control.

19.73 Communication :- Telephonic communication shall be provided between the pair of electric key transmitters when they are in different locations. Where direct communication is not possible, a bell shall be provided near each electric key transmitter.

19.74 Keys :- It shall not be possible to insert and operate the key transmitter by any key other than the one for which the key transmitter is intended. It shall also be ensured that the key of any one transmitter at a station does not fit in any other key transmitter at the same station except its counterpart.

19.75 Sealing :- Electric key transmitter cover shall be securely sealed.

SECTION 'K' - ELECTRIC LEVER LOCK

INSTALLATION

19.76 Type:- Electric lever lock shall be of an approved forced Drop type. It shall be provided with economizer contact and lock in proving contacts.

19.76.1 Lever lock with 200 mm stroke shall be installed vertically on a rigid frame on under frame in .cabin basement in case of single wire lever frames & as per approved plan when used in conjunction with ground frames. Installation of lever lock with 40 mm stroke when used in double wire lever frame shall be done behind the levers. When this lock is used in conjunction with an 'E' type lock, it shall be mounted on a suitable rigid frame.

19.76.2 The lock slide & lock plunger shall be free from any jamming.

19.76.3 The locking face of locking notches for lever locks with 200 mm stroke shall be cut clean & square and case hardened preferably in workshops to suit the site requirements.

19.76.4 When circuit controller is built into the lever lock, it shall be ensured that it keeps engaged with lock slide throughout the stroke till extreme positions.

19.76.5 The locking notches for lever locks with 40 mm stroke shall only be cut in workshops & depth of notch shall be 4 mm + 0.2 mm. The notches shall be cut radially.

19.76.6 The force drop mechanism shall be effective at all the locking positions of the levers.

19.77 The circuit controller contact segments shall be so cut that the contacts will not close in other than the required position refer para 19.47.4.

19.78 The lever lock cover/covers shall be properly fitted and sealed. Where lever lock is not provided in cabin basement, it shall be securely locked also.

SECTION 'L' - SIGNAL INDICATOR

19.79 Location :- Signal Indicator/Repeater shall be provided nearest to the place from which the signal is worked and shall be clearly visible.

19.80 Lightning and power protective devices shall be provided where required.

19.81 Audible Warning :- Audible Warning device, where provided, may be common to all light indicators.

19.82 Wiring :- Wires leading from the indicator shall be suitably protected.

19.83 Signal Arm & Light Repeater

19.83.1 Lamp proving device for each aspect

(a) For oil lit lamps :- Thermostat expander contact shall be of an approved type.

(b) For Electric lamps used for semaphore signals :- Suitable Electric/Electronic/Optical sensor shall be provided.

19.83.2 Arm Proving :- Circuit controller used for semaphore arm proving shall be adjusted as per para 19.47.4.

19.83.3 Arm indicator used for semaphore signal shall give 'WRONG' indication except for indications covered in para 19.47.4.

19.83.4 Group Light indicator for semaphore signals :- Each signal light to be indicated need not to be provided with an individual light indicator. Lights on the same bracket signal or gantry may be series wired for group indicator.

19.83.5 Battery Boxes :- Battery Boxes provided for the indication battery shall be substantial and secured against any unauthorized interference and be located at or nearest the signal.

19.84 Colour Light Signal Indicator

19.84.1 Lamp proving relay of an approved type shall be used.

19.84.2 Colour Light Signal Indicators :- Colour Light Signal Indicators shall repeat the 'ON' and each one of the 'OFF' aspect of signal.

19.85 (Para left blank intentionally)

19.86. (Para left blank intentionally)

SECTION 'M' - FUSES

19.87 FUSES

19.87.1 Fuses shall be of an approved type. Normally non-deteriorating type, 'G' type, alarm or cartridge type fuses shall be used. When fuse is not provided with fuse blown of indication, additional indication circuit may be provided.

19.87.2 At the time of commissioning of any signalling installation, the normal load current of every circuit shall be measured and recorded. These recorded values shall be checked with the theoretically obtained values. Fuse of correct capacity which should be not less than 2.5 times the rated current, shall be provided.

19.87.3 When there is a case of fuse blowing off, the concerned circuit current shall be measured and compared with the original recorded value. If there is a variation, action shall be taken to locate and remove the defect before a new fuse is inserted.

SECTION 'N' - EARTH CONNECTIONS

19.88 EARTH CONNECTIONS

19.89 Separate earth shall be provided for each block instrument at a station

19.90 The resistance of earth for signalling circuits shall not exceed 10 ohm. If the resistance is more than 10 ohm, steps to reduce the earth resistance shall be taken as indicated in paras 19.92. If it is still not possible to reduce the value below 10 ohm, even with the adoption of these methods, additional earths may be provided in parallel.

19.91 Where more than one earth is used , the distance between Earthing pipes shall not be less than 3 metre. The conductor leading to these earthings shall be electrically insulated from each other throughout and also from metallic structures connected to different earths.

19.92 Method of obtaining Earth

19.92.1 Earthing arrangement shall normally consist of one or more galvanized iron pipes of not less than 38 mm internal diameter and not less than 2.5 metre in length with a spike at one end and a lug at the other for connecting the earth lead or galvanized iron/steel rods of not less than 16mm dia or copper rods of not less than 12.5 mm dia and of not less than 2.5 metre length. While the pipe is embedded vertically, the rod electrodes are driven vertically in the ground. When a rocky soil is encountered at a depth of less than 2.0 metres of the length of this electrode, the electrode may be buried inclined to the vertical, the inclination being limited to 30�. from the vertical. Earth electrodes shall not be buried in a position likely to cause an obstruction or where it is likely to be damaged.

19.92.2 The resistance of these electrodes in a soil of uniform resistivity decreases with depth but there is little to be gained by driving the rod to more than 3 to 3.5 metres. Also the decrease in the resistance with increase in rod diameter is not significant. It is, therefore, recommended to use the rod electrodes of such diameters as can easily withstand the strain of driving.

19.93 Earthing Leads

19.93.1 Earth wires shall be protected against mechanical damage and possibility of corrosion particularly at the point of connection of earth electrode.

19.93.2 The earthing lead shall be mild steel flat of size 35mm x 6mm or copper wire of 29 sq. mm cross sectional area (19 strands of 1.4 mm dia). In case the conductor is buried underground, It shall be protected from corrosion by an application of suitable anti-corrosive paint or bitumen or varnish. The length of the cable so treated shall extend half a metre beyond the buried length.

19.93.3 The earthing lead shall be soldered or crimped on a lug, which shall be bolted to the earth electrode. The nut & bolt to be painted with anti corrosive paint.

19.94 The site for earthing shall be chosen in the following order of preference :-

(a) Wet marshy ground and grounds containing refuse, such as ashes, cinders and brine waste.

(b) Clay soil or loam mixed with small quantities of sand.

(c) Clay and loan mixed with varying proportions of sand, gravel and stone; and

(d) Damp and wet sand and peat.

19.95 A site which is naturally well drained shall be chosen. A water logged situation, however, is not essential unless the soil be sand or gravel. Perennial wells may also be used as sites for earth electrodes with advantage where the bottom of the earth is rocky.

19.96 Electrodes shall preferably be situated in a soil which has a fine texture and which is packed by watering and ramming as tightly as possible. Where practicable, the soil shall be sifted and all lumps broken up and stones removed in the immediate vicinity of the electrodes.

19.97 Where soil conductivity is poor, the chemical treatment may be resorted to improve the same. Common salt together with charcoal in alternate layers is generally used for this purpose and the addition of less than one part by weight of salt to 200 of soil mass may reduce the resistivity by 80% but there is little advantage in increasing the salt content above 3%. Calcium chloride and sodium carbonate are also beneficial.

19.98 Use should be made where possible of natural salts in soil produced by bacteriological action on decaying plants. The resistivity of the soil on which plants are growing will be less than that of a similar soil in the absence of plants.

19.99 As far as possible, the earthing arrangement shall be located in the natural soil. The made-up soil which has not consolidated or is likely to be eroded by weather, shall be avoided.

19.100 The minimum clearance of equipment earths from system earths provided by the Electrical Department either of the Railways or of the other Administrations shall be 20 metres.

19.101 Ashphalt or concrete cover of about 50mm thickness around the Earth for a radius of 1 metre to retain the soil moisture is desirable.

19.102 Earth Resistance:- The total resistance of an 'earth' is the sum of three separate resistances, viz.,

(a) the resistance of the conductor joining the earth electrode to the installation;

(b) the contact resistance between the surface of the earth electrode and the soil, and

(c) the resistance of the body of soil surrounding the earth electrodes.

Normally the first two resistances are negligibly small compared with the third; so, the resistance of an 'earth' is primarily determined by the nature of the soil and not by the electrode itself.

19.103 Under ordinary soil conditions, use of galvanized iron or mild steel electrode is recommended. In cases where soil corrosion is likely to be excessive, it is preferable to use either copper or copper clad electrode. The electrodes shall be free from paint, enamel or grease.

19.103.1 Earth tester normally used for measurement of earth resistivity comprises of the current source and meters in a single instrument and directly read the resistance value.

CONNECTION FOR A FOUR TERMINAL MEGGER

When using a megger as shown below, the resistivity may be evaluated from equation as given below:

19.103.2 Test Procedure :- At the selected test site, four electrodes are driven into the earth along a straight line in a chosen direction at equal intervals' S'.

The depth of the electrodes in the ground shall be of the order of 10 to 15 cm. The megger is placed on a steady and approximately level base, the link between terminals P1 and C1 opened and the four electrodes connected to the instrument terminals as shown in the fig. An appro. range on the instrument is then selected to obtain clear readings, avoiding the two ends of the scale, as far as possile. The readings are taken while turning the crank at about 135 rev/min.

Resistivity is calculated by substituting the values of 'R' in the equation
P = 2 л SR
Method of finding out the resistance of an Earth -
Refer annexure 27 chapter XVIII

MAINTENANCE

19.104 Watering :- Earths shall be regularly watered.

19.105 Earth connections :- All Earth connections shall be carefully examined and kept intact and joints soldered. The wire between each earth and the connected equipment shall be electrically isolated.

SECTION 'O' - PAINTING OF ELECTRICAL SIGNALLING EQUIPMENT

19.106 Electrical signalling equipment shall be painted in accordance with the Colour Scheme shown for the respective items in Annexure-29.

19.107 Painting :-The provisions in the Chapter XII para 12.135 shall be adhered to. COLOUR LIGHT SIGNALS

19.108 Cleanliness of Lenses

19.108.1 Lenses, glasses and lamps shall be kept clean. A dry soft cloth free from lint and abrasives shall be used for cleaning.

19.108.2 Housing shall be kept clean and opening in inclement or stormy weather avoided. The condition of the gasket shall be checked to ensure that rain water does not have access to the interior of lamp unit.

19.109 Replacement

19.109.1 Defective lenses and glasses must be replaced immediately.

19.109.2 The frequency of replacement of lamps shall be decided by CSTE of Zonal Railway.

19.109.3 When double filament lamps are used, they must be replaced when one filament fails. It is preferable to give audio/visual indication at the place of operation.

19.109.4 New lamp shall be pre-tested as per approved instructions before putting into use.

19.110 Maintenance checks :- The following checks shall be made periodically :

19.110.1 The bulb shall be properly seated and contact springs have adequate tension.

19.110.2 The signal focussing shall be checked and adjusted periodically.

19.110.3 All adjusting nuts are properly tightened.

ELECTRIC SIGNAL MACHINES

19.111 Cleanliness :- Machines shall be kept in good condition free from rust, dust and dirt.

19.112 Lubrication :- All gearing and bearings shall be lubricated according to manufacturers' instructions and free from grit and dirt.

19.113 Contacts :- All contacts shall be kept clean and in proper adjustment.

19.114 Commutators and Brushes

19.114.1 Commutators shall be clean, smooth and have a bright appearance. These should be cleaned with chamois leather.

19.114.2 Brushes shall be kept clean and properly bedded on the commutator. Brushes shall have proper pressure and shall be free in brush holders. Brushes shall be replaced when excessively worn-out or hardened.

19.115 TESTS :- The machine shall be tested by actual operation to see that:

(a) On closing the machine circuit, the motor operates smoothly, the hold off device is effective and the arm is taken 'OFF' correctly. If the motor does not operate smoothly and the hold off device is not effective, it is evidence of a faulty operation, which must be corrected.

(b) On opening the machine circuit, the signal arm returns to the 'ON' position smoothly without jerks. Ensure snubbing is effective and there is no tendency to stick.

(c) Normal and reverse stop provided outside the machine shall be properly adjusted so that the machine stops without any jerk in both 'ON' & 'OFF' positions.

(d) The position of the arm is correctly repeated on the arm indicator, if provided.

(e) Manual check lock when provided, shall be effective.

(f) Test the minimum operating values of the signal machine motor and the hold off device at least once in 3 months.

19.115.1 The maintainer shall test as per 19.115(a) to (f).

19.115.2 Each Inspector in charge of electrical apparatus shall perform the following periodical tests :-

(i) test the minimum operating values of the signal machine motor and the hold off device at least once in 3 months;

(ii) test the machine motor and hold off device at minimum operating values. If the motor does not operate smoothly and the hold off device is not effective, it is evidence of a faulty operation, which must be corrected. It should be ensured that there is no tendency of jamming of the arm in 'OFF' position.

(iii) test for effectiveness of the snubbing.

ELECTRICALLY LIT SEMAPHORE SIGNALS

19.116 MAINTENANCE

19.116.1 Battery provided for lighting of signals shall be maintained regularly.

19.116.2 Working of photoelectric switch shall be checked whenever the Maintainer makes his rounds.

19.116.3 Focussing of signal lamps should be done regularly. ELECTRIC SIGNAL REVERSERS

19.117 The electric reversers shall be so maintained that -

19.117.1 All moving parts work freely and are well lubricated, special care being taken during rainy weather to prevent rusting and sticking of parts. Parts requiring lubrication shall be oiled once a fortnight with high grade lubricating oil to Specification NO. IS. 1628. Ball bearings must not be oiled but filled with graphite grease (Grease A. No. 0 to IS 408). Dash Pot assembly shall be checked at least once in a year and if the oil is lower than 35mm above the bottom of sliding cylinder, insulating oil to specification No. IS.335 shall be used to bring the oil up to the level.

19.117.2 There is no tendency for the reverser to hold when de-energised.

19.117.3 The coil core does not retain any magnetism. The connection of the coil shall be periodically reversed to eliminate any such possibility at least once in a month. The surfaces of armature and core should be properly cleaned from dust. The armature must be kept free from oil or grease.

19.117.4 All mechanical connections to the reverser are properly aligned and work freely.

19.117.5 All terminal screws, lock nuts and locking screws are tight and split pins opened.

19.118 TESTS :- Each electric reverser is periodically tested by -

19.118.1 Taking 'OFF' the signal and replacing to 'ON' by putting back each control separately. The signal must go to 'ON' as soon as any one of the controls is replaced to 'ON'. Ensure that the dash pot is in proper working order.

19.118.2 Pulling the lever which operates the signal slowly without obtaining the electrical control. The signal shall not come to 'OFF'. Alternatively, efforts may be made to take 'OFF' the signal by pulling the wire slowly at the signal. The signal shall not come 'OFF' and the reverser shall not show any tendency to stick.

19.118.3 The voltage at the reverser coil terminals shall be tested. It shall not be more than 25% above the rated voltage.

19.118.4 It shall not be possible to lower/raise the signal arm manually from its 'ON' position without electrical control.

19.118.5 The insulation and continuity of the coil of the reverser must be checked once in 3 months.

19.118.6 The maintainer shall test as per para 19.118.1 to 19.118.4.

19.118.7 The Section Engineer shall test as per para 19.118.1 to 19.118.5.

ELECTRIC POINT MACHINES

19.119 Cleanliness :- Machines shall be kept in good condition free from rust, dust and dirt.

19.120 Lubrication :- All gearing and bearing shall be properly lubricated according to manufacturer's instructions.

19.121 Commutator, Brushes & Electrical Connections :-

19.121.1 Commutator shall be kept clean, smooth and have bright appearance. Commutator may be cleaned with chamois leather Under no circumstances, shall emery paper be used.

19.121.2 Brushes shall be kept clean and properly bedded on the commutator. Brushes shall have proper pressure and shall be free in brush holders.

19.122 All cables connections on terminal, motor terminal etc. shall be checked for intactness.

19.123 All tail cables shall be checked for their insulation as per periodicity given in Annexure 30.

19.124 Adjustment of Contacts :- Contacts shall be clean, free from pitting and in proper adjustment.

19.125 Rain water drainage arrangements shall be checked especially prior to and during rainy season.

19.126 FIXING NUTS AND SCREWS

19.126.1 Fixing nuts and screws of newly installed point machine often tend to get loose. Care shall be taken to attend to them and readjust where required. To prevent this, check nut with spring washer shall be provided.

19.126.2 All moving parts including locking Dogs and notches slides, etc. shall be checked for chamfering or undue wear. Where badly worn-out, the relevant parts shall be promptly replaced.

19.127 TESTS

19.127.1 Obstruction Test :-The point driving rod and the lock connections of the machine must be so adjusted that with 5 mm thick test piece obstruction placed between the switch and the stock rail at 150 mm from the toe of the switch:-

i) the point cannot be locked;

ii) the point detector contacts should not assume the position indicating point closure

iii) Friction clutch should slip.

19.127.2 The Maintainer shall check whether the current required to operate the machine in either direction is the same (approximately). The reason for unbalance, if any, shall be investigated and eliminated.

19.127.3 Test the spring in each switch and ensure sufficient spring. It shall not be too excessive to cause excessive wear on machine part, neither it shall too less to hold the switch against the stock rail. In either of the case, the point drive rod shall be adjusted.

19.127.4. Friction clutch where provided shall slip at a value not less than one and half and not exceeding twice the normal working current.

19.127.5 Badly worn-out pins shall be replaced; the holes shall be reamed out and fitted with a oversized pin. Split pins where provided shall be properly split out.

19.127.6 Voltage and current shall be checked periodically at the motor terminals. This will indicate any undue friction on the points or improperly fastened terminals at cable terminations.

19.127.7 Cable and wire insulation and continuity tests shall be done as per Annexure 30.

19.127.8 The essential requirement for interlocking of point shall be periodically checked as per Chapter XII, Para 12.40.

19.128 It shall be ensured that during obstruction in the point, the feed to point is automatically disconnected within 1.5 times to 2 times the normal operating time of point machine and reconnects only when a fresh operation is done. Where sequential operation of point machine is done, the maximum time before disconnection may exceed to 3.5 times the normal operating time of one machine. For the machines provided with over load current protection, the feed to motor shall be disconnected with current ranging between 1.5 to 2 times its normal operating current. It shall reconnect only when a fresh operation is done.

19.129 Each Section Engineer in charge of electrical apparatus shall test the operating values of the machine and adjustments of the machine by obstruction test in accordance with para 19.127 every month. The Sectional in charge of the section shall carry out these tests once in three months.

ELECTRIC DETECTOR

19.130 The essential requirement for interlocking of point shall be periodically checked as per Chapter XII, para 12.40.

19.131 All nuts and screws shall be tightened where required. Particular care shall be taken to see that the lock nuts of the Detector and Lock Slides with lugs are kept tight. After tightening, the nut and lock nut should be turned in opposite directions towards each other to lock the nut. Slides, rollers and pins shall be lubricated with axle oil medium grade to a suitable specification.

19.132 Wires shall be kept neat and clear of moving parts.

19.133 The sleepers shall be got well ballasted and packed.

19.134 OBSTRUCTION TEST :- Before doing obstruction test, it shall be ensured that both the switches flush with stock rail properly & sufficient spring is available on each switch.

a) Insert 1.6 mm test piece between stock rail & switch rail at 150 mm from the toe of switch & operate the point to close by lever. Ensure detector contacts just make. In case the contacts do not make, manipulate the detector slide nuts to just make the contacts. Tighten check nuts on both sides of detector slide.

b) Test with a 5mm test piece. The point shall not lock and detection contacts shall not make.

c) The lock adjustment given in para 19.36 stands good for both setting of point, However, The locking shall be tested by 5 mm test piece for other setting also.

In case of failure in obstruction test, immediate remedial measure shall be taken to prevent locking of point as per Chapter XII.

19.134.1 The maintainer, Section Engineer & senior Section Engineer shall do the above tests as per  periodicity given in Annexure 30.

19.135 CIRCUIT CONTROLLER

(a) The circuit controller remains securely fixed and all mechanical connections work freely.

(b) The contacts are kept clean and properly adjusted.

(c) Wires are properly dressed and not entangled with any mechanical parts.

(d) The axle is kept lubricated by light oil.

(e) The contacts make with adequate pressure in the required position only and are properly secured.

(f)  All the split pins are split out.

RELAYS

19.136 Cleaning shall be done regularly so that dust is not deposited on the relays.

19.137 Anti-tilting arrangement for shelf type relays is available and relays shall not be tilted or turned over to close contacts and relay contacts shall not be bridged.

19.138 During routine inspection and maintenance, if high contact resistance is observed on any contact of metal to metal relays, such contacts can be cleaned. In case of metal to carbon relays either the spare contact shall be used or the relay shall be replaced.

19.139 Periodical Inspection

19.139.1 All relays used in vital circuits shall be visually inspected each time during inspection.

19.140 Section Engineer shall visually inspect the relays. During visual inspection, relay shall be taken out of service if any of the defects are noticed in respect of :-

(a) Movement of armature and contact carriage;

(b) Wiping of contacts;

(c) Arcing of contacts;

(d) Pitting or charring of contacts;

(e) Dust accumulation on contacts;

(f) Electro-plating;

(g) Corrosion, rusting of components;

(h) Crack or breakage in components;

(i) Presence of fungus and ants inside the relay casing;

(j) Charring of cover near contacts in the case of plug-in-type relays;

(k) Corrosion of Label;

(I) Absence or tempering of seal;

(m) Any other abnormal condition.

19.141 OVERHAULING

(a) Track relays of all types and line relays of only shelf type should be overhauled periodically. All other relays may not be overhauled periodically.

(b) All types of track relays should normally be overhauled every 10 years subject to a maximum of 12 years.

(c) Line relays of shelf type should be overhauled every 15 years.

(d) Overhauling period mentioned in (b) and (c) above should be counted from the date of manufacture/last overhauling.

(e) The periodicity of overhauling of track relays and shelf type line relays may be reduced by the Railways depending upon intensity of traffic and other local conditions obtaining thereon, such as heavy suburban sections and major route relay interlocking installations.

(f) All metal to carbon contact miniature plug-in type relays other than track relays should be overhauled only when they are removed from service after a failure.

STATION MASTER'S SLIDE CONTROL FRAMES

19.142  Station Master's Slide Control frame shall be so maintained that-

(a) All moving parts are clean and work freely.

(b) All contact springs are kept clean, correctly tensioned and spaced.

(c) All contact making studs are tight.

(d) All wiring is in good condition and properly protected.

(e) Broken or worn-out springs and studs shall be replaced.

(f) SM lock is effective to lock all the slides both ways.

(g) All slides and locking dogs are kept lubricated / graphited.

(h) Slide frame is kept properly sealed and locked.

19.143 Testing and Overhauling : Mechanical locking of Station Master's Slide control frame shall be maintained and tested and overhauled in accordance with the instructions laid down in chapter XIII.

ELECTRIC KEY TRANSMITTERS

19.144 Key transmitters shall be so maintained that-

19.144.1 All moving parts are clean and work freely. All contact springs are kept clean, correctly tensioned and spaced. Galvo functions satisfactorily.

19.144.2 The respective keys turn freely in the transmitter and the cover is correctly secured.

19.144.3 The keyholes are such that the only correct transmitter key can be inserted in each transmitter.

19.144.4 All wiring is in good condition and is properly protected.

19.144.5 While transmitting the key, the contacts shall break and make in proper sequence.

19.145 Testing of key Transmitter :- Key transmitters shall be tested periodically for the following :-

(a) Effectiveness of the forced lock arrangement;

(b) It shall not be possible to extract the key once inserted and locked in the key transmitter unless the control from the other end is obtained

(c) It shall not be possible to release the key in jerks or any other irregular means

(d) Check the insulation resistance of current carrying components

ELECTRIC LEVER LOCK

19.146 Electric Lever locks shall be so maintained that -

19.146.1 All moving parts are clean, oiled and work freely.

19.146.2 The lock armature works freely and in the case of Forced Drop Locks, the lock is properly forced down for each locking position.

19.146.3 The face of the locking notch and the lock face is not worn-out.

19.146.4 The working current shall be within the rated value.

19.146.5 All terminal screws, lock nuts, locking screws, etc. shall be kept tight.

19.146.6 Sealing & locking is intact.

SIGNAL ARM AND LIGHT INDICATORS

19.147 The following instructions in regard to maintenance of signal Arm and Light Indicators shall be observed :-

(a) Indications of the signal arm indicator correspond to those detailed in para.

(b) Light Indicator works freely and indicates light 'IN' or 'OUT correctly. Any other lamp proving arrangement of electrical / electronic/ optical type is working correctly.

(c) The thermostat or expander is kept correctly adjusted and in working order.

(d) The audible warning device where provided is in working order.

(e) All lightning and power protective devices are in working condition.

(f) All connections from the lightning protector to Earth are continuous and in good order.

(g) Batteries are kept clean, terminals and links are properly tightened and are free from dirt and corrosion.

(h) All wiring is in good condition and properly secured.

MAINTENANCE SCHEDULES

19.148 The maintenance schedule for various items of Electrical Signalling equipment shall be as in Annexure 30. At stations having dense traffic and high speeds, the Railways may prescribe more frequent inspections, if considered necessary.

Annexure 29

Annexure 30