OHE ASSETS OF MAIN LINESr. No Item
MANSAROVER TO SINDHI CAMP
ROCS SECTION
1 Date of commissioning - -
2 Track KM 18.689246 529.854
3 Contect wire 23.627836 1.067
4 Massenger Wire
24.48162
-
5 OPC 19.54 1.13
6 BEC 19.36 1.13(TEW)
7 RC 18.5 1.13
8 IB 20 2
9 Cantilever 762 -
10 Section insulator 9 -
11 Cross Over 2 -
12 Gas ATD 36 (A-8,B-5,C-23) -
13 BWA ATD - -
14 Over lap 23(IOL-13, UIOL-10)1(UIOL)
15 Turn Out 3 -
16 Isolator 10 -
17 8X8 Mast 470 -
18 B-series Mast(7.00) 102 -
B-series Mast(8.50M) 10 -
19 PORTAL 9 -
20 RSJ 22 -
21 DA 80 80
OHE ASSETS OF DEPOTSr.No. Item YBD
1 Date of commissioning -
2 Track KM -
3 Contect wire -
4 Massenger Wire -
5 OPC -
6 BEC -
7 RC -
8 ITL -
9 Cantilever 295
10 Section insulator 27(galland11,rail 16)
11 Cross Over 1
12 Gas ATD 0
13 BWA ATD 28
14 Over lap 17(UIOL)
15 Turn Out 21
16 Isolator 19 (SS-15,DM-4)
17 8X8 Mast 69
18 B-series Mast 39
19 Two Track Cantilever 6(TTC)
20 portal BFBU 18
21 FP B-200 24
22 RSJ 8X6 22
23 DA 6X6 40
24 Earth Pit 71
OHE system adopted in JMRC
•Cantilever Assembly
•Mast & Implantation
•Steady Arm & Encumbrance
•Size of Contact wire and Tension in OHE.
•Droppers and Jumpers.
•ATD
•Section Insulator
•Neutral Section arrangement.
•Earthing and Bonding
•Return Conductor and Booster Transformer.
•OHE Parameters, OHE Sectioning, OHE Spares and T&P, OHE
Inspection & Maintenance Vehicles
•OHE Inspection & Maintenance Schedules
4
STAY ARM
Stay Arm comprises of dia 38 mm (Small) size tube and an adjuster at the end to keep the bracket
tube in position. It is insulated from mast by stay arm insulator.
Bracket tube comprises of dia 49 mm and insulated by bracket insulator. Catenary is supported
from this member by catenary suspension bracket and catenary suspension clamp.
Registerarmcomprisesofdia38mmtubetoregisterthecontractwireinthedesiredpositionwith
thehelpofsteadyarm.
Steadyarmcomprisesofdia25mmBFBsectionmadeofaluminium-alloytoregisterthecontact
wiretotherequiredstaggerandtotakethepushupofcontactwire.Itisalwaysintension.
Bracket tube Register Arm
•Steadyarm.
ROCS in Tunnel and Underground Section.
6
ROCS Cantilever different Part
7
Transition element from Flexible to Rigid OHE
The termination of the contact wire coming from the flexible catenary is terminated
in the ROCS through a special come along clamp inserted on the last conductor rail
Details of Mast Used in JMRC
SNType of Mast DimensionHeight Remarks
1BFB ( BroadFlange
Beam )
8’’X8’’ 6.2 m Used in single
cantilever location of
viaduct
2BFB ( BroadFlange
Beam )
8”X8” 9.5 m Used at Graded
section / Depot.
3RSJ (Rolled Steel
Joist)
8”X6” 6.2 m Used at BT location
4RSJ (Rolled Steel
Joist)
8”X6” 9.5 m Used in Depot for
mounting isolators.
5 B –175 175X300 mm 6.2 m Multiplecantilever
Location, Anchor
location.
6 B –200 200X300mm 8.5m Switching posts for
cross feeders
9
Type of Mast
Implantation
•The horizontal distance from the nearest face of traction mast to the centre line of
the track .Track gauge =1435 mm
•Centre of track = 717.5 mm Say 71.75 cm
•hence put tape (non metallic) at 71.75 cm at inner edge of track & stretch till it reaches to
the nearest face of the mast. The measured distance at face of the mast is implantation of
the mast Centre Line
of the TrackFace of the
Mast
Steady Arm
•In JMRC bent steady arms are used for better
performance in dynamic condition and it
ensures better current collection at register
point of cantilever.
12
Encumbrance
•The axial distance on vertical plane between the
Catenary and the contact wire at support the
encumbrance shall normally be 0.90 M
.
Encumbrance
Size and tension of Contact and Catenary wire
•Contact wire of 150 Sq mm hard drawn copper conductor is used in JMRC
in contrary to 107 Sq mm Copper in IR.
•The reason behind using of larger cross section area is that 1200 kgf
tension is applied in both contact and catenary wire for better current
collection. Whereas in Railways 1000 kgf tension is used.
•The larger cross section area of contact wire also increases the breaking
load of contact wire.
14
Contact Wire Splice Catenary Wire Splice
Droppers
•In JMRC 12 mm bronze flexible cables used as
droppes in contrary to 5 mm hard copper wire
with loops in Indian Railways.
•The risk of dropper breakage due to sparking
in loops in IR has been resolved by using
flexible crimped type droppers in JMRC.
15
Droppers in JMRC
16
Jumpers
•Fit and Forget Type of Jumpers used in OHE to
maintain electrical continuity and ensure equi
potential within spans, across insulated overlaps,
crossovers and in the sectioning posts.
•The advantage of crimped jumper is that it ensures
good contact thereby reducing contact resistance in
turn reducing the chances of localize heating. Less
maintenance is required.
17
Jumpers Arrangement
G Jumper
18
In span jumpers
•In JMRC 26 sq mm, in span jumpers are
provided in every 200 m between contact and
catenary for current distribution in contrary to
65 sq mm, jumpers in every 350 m in Indian
Railway.
•By increasing no. of jumpers in each tension
length the distribution of current between
Contact and Catenary improves.
19
Gas type ATD
For critical locations where sufficient room is not available for counter weight
installation , Due to less travelling distance available for movement of counter weight and to
avoid falling of weight on road due to snapping of rope, Gas Type ATDs are used in JMRC
Gas Type ATD is proposed to be used. In gas tensioners (Gas ATD) regulation is
achieved by cylinder piston arrangement filled with the pressurized Nitrogen (N2) gas.
In this arrangement piston is fixed on mast and cylinder is movable and is connected
to OHE wires. Three type of Gas ATD’s are available as per half tension length.Total 41
nosGATD are in service in JMRC
A) Type ‘A’ -Suitable for tension length up to 297 m
b) Type ‘B’ -Suitable for tension length up to 468 m
c) Type ‘C’ -Suitable for tension length up to 721 m
Construction and working of GATD
23
Section insulators
•In JMRC light weight section insulators are
installed to achieve spark less current
collection in high speed and can be used in
main lines. In Indian Railway generally heavy
section insulators are used in only crossovers.
•Provision of SI in main line give the flexibility
for installing switching posts at will.
24
Section insulators in JMRC
25
Neutral Section
•In JMRC magnets are used at before and after
of Neutral Section for proper opening and
closing of VCB’s before and after neutral
section. In Indian Railways driver of the trains
normally opened the VCBs at DJ open board
location.
•NSCZ boards also provided to rescue the trains
in case of train stuck at neutral section.
26
27
SHORT NS
Design of NS(AF design)
R B
•PTFErodgiveslargerAirgapcausingalmost
nochanceofwrongphasecoupling.This
reduceschanceofdamagetoNSand
pantographboth.
•Midpointearthingfurtherminimisescoupling
oftwodifferentphases.
Advantages of Short Neutral sections
Earthing & Bonding System
•All viaduct is non conducting concrete structure. Hence, special earthing
arrangement has been provided.
•Overhead Protection Cable (OPC) on top of OHE network and Buried Earth
Cable (BEC) along track are run to provide complete earthing. All masts are
connected with OPC.
Earthing & Bonding System
•Every pier is provided with a non structural earthing bar (T-20). Earthing
terminal is provided at the top of earthing bar.
•All segments and track plinths are interconnected through jumpers.
•Plinth Jumpers are connected to Buried Earth Conductor at every 100 meter.
34
35
Return Current and Booster Transformer
Simple 1x25 kV ac traction systems can produce inductive
interference in telecom lines and other equipment.
Booster transformer system reduces that inductive interference.
Return Current and Booster Transformer
Singlesystem(ST):Returncurrentsystemmadebyrailsandburied
earthingcable(ifitexists).
•Theoverheadcatenaryisfedelectricityat25kVAC(single-phase)from
tractionsubstationswhicharepositionedatfrequentintervals
alongsidethetrack.Currentsuppliedbysubstationsflowsthrough
catenarytotherollingstockandreturnsthroughrails.Insomecases,
thissystemalsousesoneburiedearthingcablelocatedalongthetrack
andconnectedtotherailsatregularintervals.Inthisway,returnsystem
ismadebyrailsandburiedearthingcable.
Return Current and Booster Transformer
BoosterTransformer(BT)System:Returnconductorcloseand
parallelcatenarywire.Returnconductorisconnectedtotherails.
•Inthissystemthereisareturnconductorthatisclosetoandparalleltothecatenarywire.
•Returnconductorisconnectedtotherails(andearthed).
•Periodically(every2.5km),therearebreaksinthecatenarywherethesupplycurrentisforcedto
flowthroughonewindingofaboostertransformer.Theotherwindingisinserieswiththereturn
conductor.The1:1turnratiooftheBTmeansthatthecurrentinthecatenarywillbeverynearlythe
sameasthecurrentinthereturnconductor.
•Currentthatflowsthroughtherollingstockgoestotherailsbutthenupthroughaconnectingwireto
thereturnconductorandthroughitbacktothesubstation.
•Insulatedrailjointsarealsoprovided--thisensuresthatcurrentflowsintherailsonlyinthe
particularsectionwherethetrainispresent.Atallotherplaces,theinductiveinterferencefromthe
catenarycurrentisnearlycancelledbythatfromthereturncurrent,thusminimizingtheinterference
effects.Theproblemofstrayearthcurrentsisalsoreduced.
Return Current and Booster Transformer
•A special rail bond
used to bridge an
insulated rail joint
in ac track circuited
sections in areas
equipped for
electric traction
.
Parameters of OHE in JMRC
SN Items Values
1 Height ( Elevated ) 5 m No Variation
2 Height ( Under Ground ) 4.318m No Variation
3 Stagger (Straight) +/-200 mm No Variation
4 Stagger(Curve) +/-300 mm No Variation
5 Min.Clearance betwlive parts
and structure (UG)
270 mm (Long time)
170 mm ( Short time )
Within limit
6 Min.Clearance betwlive parts
and Bodies of vehicle (UG)
290 mm ( Long Time )
190 mm ( Short Time )
Within limit
7 Min.Vertical Clearance betwlive
parts and Earthed structure or
Bodies of vehicle (Elevated)
320 mm ( Long Time )
270 mm ( Short Time )
Within limit
8 Min.Lateral Clearance betwlive
parts and Earthed structure or
Bodies of vehicle (Elevated)
320 mm ( Long Time )
220 mm ( Short Time )
Within limit
41
Sectioning of OHE
SN Type Quantity Location
1 Total RKM 9.7 km (El -9.438 km,
UG –0.262 KM )
2 Elementary Section 14
1 Sub Sectioning (SS) 2 Mansaovar, Sindhi
Camp
2 Sub Sectioning and
Paralleling (SSP)
1 Vivekvihar
3 Feeding Post (FP) 3 Mansarovar, Depot,
Sindhi camp
4 Sectioning and
Paralleling (SP)
1 Civil lines.
42
Spares and T&P for OHE maintenance
SNWingMajor spares Major T&P Additional requirement
1OHEAll OHE spares like
differenttypes of
conductor, jumpers,
cantilever assemblies,
Isolators, Masts, SIs,
etc. already procured
by JMRC.
T&P items like Earth
tester, multimeters,
Tirfors, pull lifts,
meggars, tool boxes,
crimping tools, slings,
D-sackles, discharge
rods, safety belts,
helmets, Contact wire
diameasuring devices,
height and stagger
gauges etc already
procured by JMRC.
Someitems which was
left out in contract like
Gas ATD, BWA ATD,
Short neutral Section,
PG clamps, all nut bolts
etc and few spares and
T&P’s felt less in
quantity in contract are
under procurement.
43
Maintenance and Inspection Vehicles
Tower Wagon Emergency Vehicle
OHE Inspection & Maintenance
SN Activity Schedule Checking points
1 Foot Patrolling Fortnightly Foundation ( At Grade )
OHE mast and portals
Anchor
Bracket Assembly
Section insulator
Regulating Assembly
OHE Span
Isolator
RC & BT
Earthing
2 Section Insulator Monthly Cleaning of core insulators
Tightness of all nuts and bolts
Checking of Runners
Pantomovement checking and balancing
3 Neutral Section Monthly Cleaning of PTFE rod.
Checking of Runners
Checking of balancing
OHE Inspection & Maintenance
SN Activity Schedule Checking points
3 Section Insulator
( Other than
Polluted Zone )
Quarterly Cleaning of core insulators
Tightness of all nuts and bolts
Checking of Runners
Pantomovement checking and balancing
4 Gas ATD Half YearlyTightness of all nuts and bolts
Measurement of X value and ramp extension
Cleaning of Ramp
Checking of Gas pressure.
5 BWA ATD Half YearlyFree movement of balance weight
Greasing if required
Checkingof SS rope
Measurement of X-Y value and adjustment if
required.
6 Current collectionHalf yearlyThe points detected during current collection to
be attended on priority basis.
OHE Inspection & Maintenance
SN Activity Schedule Checking points
7 ST,BT InsulatorHalf YearlyCleaning of ST,BT insulator of polluted zone.
8 Cross over/TOYearly Checking of height and stagger ofmainline
OHE and T/O OHE.
Checking of sag in section insulator
Pantomovement checking
Check bracket of obligatory mast.
9 Overlap Yearly Check height and stagger of IR and OR.
Check clearanceof OHE.
Check jumper and PG
Check pantomovement.
10 Cantilever Yearly Check and tight all nut bolt.
Cleaning of insulator.
Measurement of height and stagger.
OHE Inspection & Maintenance
SN Activity Schedule Checking points
11 Contact wire dia
measurement
yearly Contact wire diashould be taken in different
locations where wear rate is high. A register to
be maintained to check wear rate. Marking to
be done on locations for future reference.
12 Tree trimmingYearly Every year in January joint inspection to be
carried out with P Way to identify the trees
nearby OHE.
13 Kite, Thread / Bird
nest removal
Yearly Should be attended on priority basis as
observed during Foot plating and patrolling.
With special emphasize in bird nesting season
from April to September
OHE Inspection & Maintenance
SN Activity Schedule Checking points
14 POH 4.5 yr Cantilever : One complete cantilever in identified
polluted zone is to be replaced and its thorough cleaning
and detailed examination is done of its moving parts for
free movement and its rusted parts to take decision for
level of maintenance. Check all the Cantilever
component for cracks, rust and thread damage with a
magnifying glass. The crack fittings and damage threads
fittings should be discarded. Deteriorated GI fittings and
pipes should be repaired by using cold galvanized paint.
ATD : All regulating equipment(ATD) should be replaced
with the overhauled ATD. SS rope should be closely
examined for any damage to its strands. Ends of SS rope
is also to be reversed. X & Y values to be adjusted as per
temperature chart either by wire cutting or by adjuster.
Removed ATD is to be taken to workshop and petrol
cleaned and check for any rubbing mark on pulley block,
if any replacement to be done. All lubricating holes
should be free for passage of grease. Check for free
movement of bearing of pulley block. Grease should be
applied in the bearing by grease gun.
OHE Inspection & Maintenance
SN Activity Schedule Checking points
14 POH 4.5 yr Jumpers: Dismantle all jumper
connections. Check for broken/ damage
strands. Overheating or corrosion specially
at suspension clamps & BM flange
connection.
Contact and Catenary:a) Dismantle all
Jumper connections
b) Clean the conductors by emery paper, if
there is a sign of over heating.
c) Remove kink, if noticed
d) Check the height and gradient of contact
wire.
Inspection Schedule of Officers of
OHE installation
Inspection Supervisor Manager DGM GM ED
Footpatrolling
(fullsection)
Monthly Quarterly 6 monthly Yearly As & when
required
OHEGang
(eachgang)
With gang Monthly Quarterly 6 monthly Yearly
Cab/ Foot
plate
Daily Weekly Monthly Quarterly 6 Monthly
TowerWagon Fortnightly Monthly Quarterly 6 monthly Yearly
Emergency
vehicle
Fortnightly Monthly Quarterly 6 monthly Yearly
OHEDepot Fortnightly Monthly Quarterly 6 monthly Yearly
Current
Collection
6 monthly 6 monthly Yearly Yearly As and when
required
51