|20.0 Setting of Masts
20.1 Tangent track
The standard setting i.e. the normal distance of the nearest part of the
traction mast from the centre line of tangent track shall be 2.50 m for
the broad gauge and 2.35 m for the metre gauge. The setting may be
reduced to a minimum of 2.36 m for the broad gauge and 2.14 m for the
metre gauge only In special circumstances such as yards, cuttings and
bridges etc. with the approval of the Chief Electrical Engineer of
railway concerned. In case of portal uprights, masts carrying more than
one OHE and head span masts, the setting should not normally be less
than 3.00 m for the broad gauge and 2.50 m for the metre gauge.
20.2 Curved track
The minimum setting distance of masts including portals, head-span masts
etc. on curves is obtained by adding the curve allowance and 150 mm
slewing allowance to the setting distance specified for tangent track in
para 20.1. For trunk routes and main lines where the speed may be
Increased in near future, curve allowance should be taken as per Table
HI. For other routes, branch lines and yards where there is no prospect
of Increase In above 105 km/h in near future, the curve allowance should
be taken as per Table -I for Broad gauge and Table II for Metre gauge,.
Normally, the standard setting distance on broad gauge main lines on
curves should not be less than the values given below:
a) On outside curves
|| Standard settings (m)
|i) Radius of curvature
greater than or equal to 875 m.
|ii) Radius of curvature less
than 875 m.
b) On inside curve
|i) Radius of curvature
greater than or equal to 3500 m.
ii) Radius of curvature
greater than or equal to 2350 m but less than 3500,m.
|iii) Radius of curvature
greater than or equal to 1150 m but less than 2350 m.
iv) Radius of curvature greater than equal to 300 m, but less than 1150 m.
Note: See Drg. No. ETI/OHE/G/00111 Sheet 2 also for reference.
20.2.1 In yards, where there is no super-elevation of track on curves,
the extra clearance indicated may be reduced suitably in locating masts
20.3 Masts with counter weights
In the case of masts with counterweights, the term "Setting"
refers to the minimum distance of the counter-weight from the track
centre in the worst condition. For this purpose, the displacement of the
counter-weight due to wind transverse to the track may be taken ± 50
20.4 Platform masts
The setting of masts on platforms shall not be less than 4.75 m on the
broad gauge and 4.0 m on the metre gauge. As far as possible, masts
shall be located In line with other masts or obstructions on platform
and shall be of minimum possible dimensions and fit in with the
architectural pattern prevailing in the vicinity. Locations of masts
opposite to public entrances, exits, staircase's, gang ways shall be
avoided. No live conductor should be run over platforms.
20.5 Masts near signals
The visibility of signals should be kept in mind while deciding the
setting up masts in their vicinity. The following principles should be
observed for deciding the setting of masts near signals.
20.5.1 Colour light signals located outside all tracks.
a) Colour light signals without route indicators,
i) Where no approach
signal is provided
The minimum setting of mast before signal should be 3.25, 3.10, 3.05,
2.90 and 2.75 m for distance upto 80 m, beyond and upto 110 m, beyond
and upto 190 m, beyond and upto 270 m and beyond and upto 400m
ii) Where approach signal is provided and for signals other than distant
The minimum setting of masts before the signal should be 3.25, 3.10,
3.05,2.90 and 2.75m for distance upto 50m, beyond and upto 70 m, beyond
and upto 115 m, beyond and upto 160 m and beyond and upto 240 m
b) Colour light signal with route indicators:
i) With horizontal route indicator:
The minimum setting of masts before the signal should be 3.72, 3.50,
3.25, 3.05, 2.90 and 2.75 m for distances upto 60 m, beyond and upto 125
m, beyond and upto 170 m, beyond and upto 215 m, beyond and upto 250 m,
beyond and upto 310 m, respectively.
ii) With other than horizontal route indicator:
The minimum setting of masts before the signal should be
3.50,3.25,3.05,2.90 and 2.75 m for distances upto 70 m, beyond and upto
130 m, beyond and upto 170 m, beyond and upto 215 m, and beyond and upto
280 m respectively.
Note: 1. See Drg. No. ETI/OHE/G/00112 also. The setting may be reduced
in special cases, conforming to Figs. 6 to 9 of ibid.
2) Setting distance may be reduced for starter signals of loop lines and
20.5.2 Colour light signals located between tracks:
a) Signals without route indicators:
No OHE mast should, as far as possible be located in the same lane as
the signal for a distance of at least 600 m before a signal. Drop arms
of portals should also not normally be located in the lane where signal:
are located, at least for a distance of 600 m before the signal.
Where this is not possible, for any reason, the signal should be mounted
on an off-set bracket. In addition, a special study should be made in
each such case in respect of three drop arms before the signal, to see
whether the drop arms can be off-set from the centre line of the lane in
a direction opposite to the off-set of the signal or alternatively
whether it is possible to shorten the drop arms. Reduction in the
signals height may also be examined.
b) Signals with route indicators:
The principles mentioned under para 20.5.2(a) should be observed in
these cases also.
Note: 1. No part of a colour light signal without a route indicator
should, as far as possible, be higher than 5.2 m above rail level. Great
care should be exercised in deciding the locations of colour light
signals with route Indicators so that the necessary minimum clearances
are available between the signals and live out of run conductors, or
pantograph sway zone.
2. On single-line sections, signals (colour light as well as semaphore)
should, as far as possible, be located on the side of the track opposite
to the OHE masts.
20.5.3 For semaphore signals located outside the track:
The minimum settings of masts before the signal should be 3.05, 2.90 and
2.75 m for the first second and next three masts respectively.
Note: For details, See Drg. No. ETI/OHE/G/00112.
20.6 Masts on bridge piers
The setting of masts on piers of bridges will be as large as possible
and Indicated by the Railway.
The setting of masts located near theoretical centres of turnouts and
diamond crossings should be 3.0 m from the nearest track for the broad
gauge and 2.75 m for the metre gauge (Ref. Fig. A1.09).
Wherever portals are proposed to be used they shall be selected with
standard clear spans (distance between face of the uprights) Indicated
In the tables IV and V. For this purpose the clear span for any location
obtained by adding the proposed setting of the two columns to the
centre-to-centre distances of the tracks spanned by the portal shall be
rounded off to the next higher standard span indicated in the tables.
The setting of the uprights of the portal shall then be adjusted to suit
the standard span selected with a minimum setting distance as specified
in para 20.2.
TABLE - IV
Standard Clear Spans
for 'N' type portals
(Spans in metres)
Nominal range : 10.0
m to 20.0 m
TABLE - V
Standard Clear Span for 'O' and 'G' type Portal
Nominal range: 20.0 m to
21.0 Over-line Structure
The requisite minimum electrical clearances (See para 3) should be
maintained under over-line structures such as over-bridges , signal
gantries, platform sheds and tunnels. The location of structures and
spans under these structures is, therefore, determined to suit the
clearances. A clearance study shall be made for all existing over line
structures. Efforts should be made to provide as large clearance as
21.2 Where adequate clearance is available, the catenary should be
erected so as to have maximum clearance from the over-line structure to
reduce the possibility of birds perching on the catenary wire and coming
in contact with earthed parts.
21.3 The catenary is normally passed freely under over-line structures.
Where this is not possible on account of restricted clearances, the
following alternatives may be adopted:
i) The catenary may be suspended from the two-faces of the over-line
ii) Suspension from over-line structure
The catenary may be suspended from the over-line structure at an
iii) The catenary may be anchored on to the over-line structure on
either side or on to special anchor structures. The anchor point should
normally be the anticreep.
iv) Special designs may be adopted inside covered station areas and on
through girder bridges, employing even regulated tramway type equipment
(contact wire only), where it is feasible.
Note: At over-line structures, the span should preferably be centrally
located as far as possible and generally should not exceed 54.0 m.
21A Polluted zone
Double insulation or insulator for polluted zones shall be used in the
(i) In tunnels (see para 19.9).
(ii) For Insulators located on the axis of the track in areas where
steam traction would be in extensive use or where smoke is likely to
22.0 25 kV Feeders
Where a 25 kV feeder is run longitudinally on traction masts, it shall
be carried on the masts as shown in Drg. No. ETI/OHE/G/05143. The feeder
may be run on either side of a mast. Two 25 kV feeders, or one return
conductor and one 25 kV feeder, may be carried on a single mast, if
necessary, with one feeder on each side of the mast.
Note: If the 25 kV feeder and OHE are of different elementary sections,
'Restricted clearance' board shall be provided.
22.2 Clearances from overhead equipment
Where a 25 kV feeder crosses overhead equipment belonging to a different
elementary electrical section, the clearance between the feeder and the
overhead equipment shall not be less than two metres under any
22.3 Clearance from line side structures
Normally, no feeder should be erected over huts, cabins, goomties,
platforms shed or other covered structures. If unavoidable the clearance
between the highest point of a covered structure and a 25 kV feeder
passing over it shall be 2 m under all conditions. In the case of a 25
kV feeder passing over an over-line structures which is not covered, a
suitable metallic screen shall be provided on the structure underneath
the feeder. The clearance between the feeder and the highest point of
the screen shall be adequate. A clearance of 2 m is desirable between
the 25 kV feeder and any part of an earthed structure for facilitating
maintenance work on the structure.
23.0 Cross-Spans at Switching Stations
23.1 Cross span arrangement
All the switching stations have gantry with two or more main vertical
supports. Cross span wires / feeders are provided on the gantry to
connect the various sections of overhead equipment by jumper
connections. The general arrangement is shown in Drg. No. ETI/OHE/G/05124.
23.2 Setting distance
The minimum setting distance of the gantry upright which is normally
aligned parallel to the track shall be 4.30 m.
23.3 Multiple, track
The general arrangement of connections at the switching stations on
double track and multiple track section are shown in drawing No. ET1/OHE/G/05125
24.0 Tramway type overhead equipment
24.1 Regulated Equipment
In tramway type equipment only contact wire is provided and is
auto-tensioned at the anchor by weight. The contact wire is supported by
swiveling type of brackets on individual masts as indicated in Drg. No.
ETI/OHE/ G/04204. Generally, the principles applicable to normal
overhead equipment are also applicable to regulated tramway equipment
except as specified below:
The regulated tramway type equipment is to be adopted for loop lines,
sidings, yards and spur lines excluding the main running line and first
loop or lines taking-off from the main running line.
The maximum span is restricted to 63 m. The general arrangement is shown
in Drg. No. ET1/OHE/G/04203.
24.1.3 Section Insulators
Where a section insulator assembly is to be provided, the provision of a
structure to support the assembly is obligatory. The arrangement is
shown in Drg. No. ETI/OHE/G/04207 Sheet 1&2.
24.1.4 The arrangement of tramway equipment at anti-creep and points and
crossings are shown in Drg. No. ETI/OHE/G/04205 and 04208 respectively.
24.2 Unregulated equipment
The general arrangement of tramway equipment to be adopted for head span
and cantilever type construction is shown in Drg No. ET1/OHE/G/04101.
The principles applicable to normal OHE are applicable to this type of
unregulated equipment except as specified below.
24.2.1 The maximum span is restricted to 30 m. In station areas, where
this type runs side by side with conventional equipment with contact and
catenary wires, the maximum span may be increased to 31.5 m.
24.2.2 Where a section insulator is to be provided the provision of a
structure becomes obligatory.
25.0 Booster Transformers
25.1 100 kVA Booster Transformer wherever necessary for suppression of
inductive Interference of P&T communication lines running in close
vicinity and parallel to 25 kV OHE may be provided separately for each
running tracks. The primary winding of the booster transformer is
connected in series with the OHE at insulated overlaps. The arrangement
of mounting and connection is shown in RDSO Drg No. ETI/PSI/115.
25.2 The Booster transformers are located at an approximate spacing of
2.66 km between each other.
25.3 The location of the booster transformer should be decided
considering the following aspects:
a) At feeding posts and sectioning and paralleling posts the booster
transformers should be located equi-distant on either side so that the
mid-point falls in front of these switching stations.
b) In exceptional circumstances where the booster transformers are not
placed equi-distant from the feeding post or sectioning post, it must be
ensured that the distance of the booster transformer from FP or SP does
not exceed 1.33 km.
c) The booster transformer should not be located:
in the vicinity of the stop signals to avoid bridging 6f insulated
overlap by locomotives pantograph, within the station limits except for
very big stations.
26.0 Return Conductors
In deciding the route of return conductors the obstructions en-route
should be taken into consideration. Besides, adequate physical and
electrical clearances should be maintained from fixed structures.
The general objectives is to run the return conductor as dose as
possible to the associated overhead equipment so as to secure maximum
compensation. Subsidiary lines such as sidings, loops etc. are not
provided with return
The return conductor will be normally run on the traction masts on the
same side as the overhead equipment. The arrangement is shown in Drg.
No. ETT/OHE/G/05307. The clearance between the return conductor and the
overhead equipment should not be less than 400 mm under the worst
The static and dynamic clearance to any part of the return conductor
from an earthed structure should be 150 mm and 80 mm respectively.
26.3 Return conductors at over-bridges
At over-bridges return conductor: may be run straight through, if
possible, as on normal structures.
26.4 Return conductors in complicated areas
In station areas having complicated track layout, it may not be
practicable to position the return conductor sufficiently close to the
associated overhead equipment to secure the required compensation. In
such cases, the route of the return conductor should be decided on the
merits of each case. Care being taken to avoid running of return
conductor over platforms.
26.5 Tension lengths of return conductors
Return conductors are normally terminated at the masts where the return
conductors are connected to the rail. They may be anchored back-to-back
at such masts.
26.6 Connections to booster transformers
At all booster stations, the return conductors for each track should be
provided with a cut-in-insulator. The return conductor is connected in
series with the secondary winding of the booster transformer and the
connections of the return conductor to the booster transformer should be
carried out in accordance with Drg. No ET1/0HE/ G/05413.
26.7 (i) The mid-point of return conductor shall be connected to the
buried rail as per RDSO's Drg. No. ETI/ OHE/G/05306 and ETI/PSI/611. The
mid-point is defined as a mid point between two consecutive booster
(ii) Mid-point of the return conductor before feeding posts shall be
connected to the buried rail on either side of the insulated overlap and
in case of sectioning posts shall be connected on either side of the
(iii) In exceptional circumstances, where mid-point does not fall in
front of feeding posts and sectioning posts, the two rail links between
return conductor and rail should be provided in front of feeding post
and sectioning post on either side of the insulated overlap/neutral
section. In these cases, mid-point should not be connected to rail.
27.0 LT Supply Transformer
27.1 Low tension power supply
230 V single phase power supply required for operation of substation
equipment e.g. circuit breakers, interruptors, etc. lighting of the
station yard, tunnels and working of colour light signals, is obtained
through 25 kV / 230 V, 10 kVA 50.Hz. single phase LT supply transformer.
It is provided at substations feeding and switching posts, stations,
block-huts and at other outdoor locations e.g. level crossings with gate
27 2 Capacity
LT supply transformers are of 10 kVA capacity. More than one transformer
are provided at large station, yard etc.
27 3 Protection
LT supply transformers are protected only by a 25 kV, Amp. dropout fuse
on the primary side and 63 A fuse (re-wireable d.c. type with 20 SWG
tinned copper wire) on the secondary side.
27.4 Mounting arrangement
The LT supply transformer is mounted on steel platform erected on the
OHE mast and connected to the 25 kV OHE through rigid aluminium bus-bar
or 50 mm2 copper jumper wire. The general arrangement of mounting and
connection is shown in Drg. No. ETI/PS1/036.
27.5 Substation L.T. Supply
At substation, in order to provide power to single phase transformer oil
centrifuging / filtration plant, 100 kVA, 25 kV/230V, 50 Hz single phase
transformers are provided,. The general arrangement of mounting and
connection is shown in Drg. No. ETI/PSI/0312.
28.0 Mast and Rail Bonds
28.1 Structure Bonds
All traction masts shall be bonded to a non-track-circuited rail as
shown in Drg.No.ETI/OHE/P/7000 (see para Z9.1). In the case of portals,
only one uprights of the portals, and in the case of head spans, both
masts of the head spans, shall be bonded to non-track-circuited rails.
28.2 Rail Bonds
The Rail bonds to connect the running rails longitudinally across a rail
joint shall be in accordance with Drg. No. ETI/ OHE/P/7030.
28.3 The cross bonds connecting two rails of track or rails of adjacent
track shall be in accordance with Drg. No. ETI/ OHE/G/05251.
29.0 Earth Wires
29.1 Sectioning and earthing
In sections where a non-track circuited rail is not available, as in
double-rail track-circuited sections, all traction masts shall be
connected together by a continuous aerial earth wire supported by the
traction masts. The earth wire shall be divided into electrical sections
not exceeding 1000m in length by means of cut-in-insulators. Each
section of earth wire shall be bonded to traction mast which should be
connected to an earthing station (Drg.No. ETI/OHE/P/7020). With two
separate earth electrodes In such a way that the interval between the
earthed structures does not normally exceed 500 m as shown in Drg.No.
29.2 In Tunnels
In case of tunnels, all the traction support structures shall be
connected together by a continuous earth wire, which may be supported
from tunnel surface. The earth wire shall be made into discontinuous
sections not exceeding 1000m and shall be connected to earth electrodes
provided not more than 500m apart and traction rail at both ends of the
No earth wire shall cross any track. Where masts required to be
connected to an earth wire are located on opposite sides of a track,
separate wire-runs shall be used for connecting the masts. In
complicated areas, masts may be connected to Individual earthing
Earth wires need be anchored only at termination of wire-runs.
30.0 Sections Arrangement
30.1 Necessity of sectioning
OHE is divided into electrically isolated sections by provision of
interruptors or isolators at overlaps and with section-insulators at
turnouts. Sectioning is provided to permit isolation of OHE in small
sections for maintenance or to isolate damaged OHE in case of
breakdown/accident and to permit diversion of trains from up line to
down line and vice-versa. However, the sectioning should be kept to the
minimum consistent with operational requirements.
30.2 Protection of isolated sections'
Protection by signal of the
Normally a stop signal is provided before the insulated overlap, i.e.
isolator so that approaching train is stopped from entering the isolated
section. Although the distance between the stop signal and the
sectioning points has not been specified in the rules, it is desirable
to provide 120 m between the stop signal and the centre line of the
insulated overlap/section insulators, i.e., the sectioning point.
30.3 Sectioning arrangements for different types of stations:
Since most of the electrified routes are on the double line section,
only double line stations have been considered.
30.3.1 Stations having no emergency cross-over:
The isolation is provided to take a block. The trains are stopped by the
stop signal. The sectioning point should be provided 120m away from the
starting signal. This arrangement enables the trains to be received at
the station. Fig.A1, 11 shows the layout.
30.3.2 The first loop line adjacent to the main is normally provided in
the same elementary section as that of the main line. No sectioning is,
therefore, required between the main line and the loop line. Only where
there are group lines comprising of 2 loops or more, sectioning should
be provided to include the loop lines in an independent elementary
section. In case of large number of loop lines, the chances of damage to
the OHE being more, they should be isolated to keep the main line
operative. The arrangement is shown in Fig.A1. 12.
FIG. A 1.12
30.3.3 Stations provided with emergency cross-overs:
At the stations provided with emergency cross-overs, the diversion of
trains from up-track to down-track and vice versa and also the diversion
of trains coming on the wrong track to the correct track is possible.
Isolation at such stations should be provided in accordance with Fig.A1.
13 so that the longest train can be pulled beyond the crossover before
backing. It is advisable to keep the advance starter sufficiently away
from the cross-over so that the longest train length can be accommodated
between the cross-over and the advance starter. Otherwise, provision
should be made in the station working rules for shunting of the trains
beyond advance starter.
30.3.4 Stations provided with emergency cross-over and loop lines:
At stations having loop lines the isolation arrangement as shown in Fig:
A1. 14 & A1. 15 should be adopted. Where space is available, the
insulated over-tap and the isolator should be provided between the
points, A & B as shown in Fig: A 1.14. Otherwise, the insulated
overlap should be provided before the point and a section insulator
provided in the loop line as shown in Fig:A1. 15.
Fig: A1. 14 &
30.3.5 Sections having one or more common loops situated on one side of
Generally the common loop is situated on one side of the main track.
Such common loop can be electrically connected only to the adjoining
main line. Stations with such a common loop also have a facing
cross-over which can be beneficially used for diversion of trains from
one line to the other without reversing. The sectioning should permit
diversion of trains from one line to the other in both the directions.
The sectioning given in Fig: A1.16 would meet these requirements.
FIG. A 1.18
Note : Where space is available the insulated overlap and isolator
should preferably be provided between (A) & (B)
For layouts having a group of (common) loops on one side, sectioning
arrangement shown in Fig. A1.17 should be followed.
Where an SSP is located the sectioning arrangement as shown in Fig.
A1.18 could be adopted. However, this arrangement cannot be adopted at
feeding posts because in that case the cross-over would be connected to
two different sectors and in case of extension of feed, the
section-insulator would be connected to two different phases and
subjected to 44 kV. Passage of electric locos in such condition would
result in bridging of 2 phases which may ' damage the section insulator
30.3.6 Common loop situated in between the two main lines:
At some stations, the common loop is provided in between the two main
lines. Such stations provided ideal arrangements for sectioning, as the
common loop can be connected to either up or down main lines through a
set of inter-locked isolators. The sectioning arrangement is indicated
in Fig:A1. 19.
30.3.7 Sectioning for the loco sheds and major yards:
184.108.40.206 Loco sheds and major yards are prone to frequent flash-over of
insulators due to pollution caused by steam/diesel shunting locomotives
and also due to switching surges from the loco transformer and sparking
of rod-gap which result in tripping of feeder breaker affecting power
supply to the main line. It is, therefore, advisable to provide a
separate feeder with a circuit breaker and required protection for all
major yards and electric loco sheds. If the yard/shed is within 4 km
from the traction sub-station, a separate feeder can be economically
run. If the yard/shed is beyond 4 km the power supply may be given by an
interrupter located in the SSP with provision to supply from either UP or
DOWN line. In case the circuit breaker or interrupter is out of service
for maintenance, alternative arrangement is made to tap the OHE,
directly through an inter-locked isolator. These arrangements are shown
in drawing No. ETI/PSI/704.
220.127.116.11 Major yards are normally separated in Up and Down yards. Each
yard is again sub-divided as Reception yard, Despatch yard, Sorting
yard, Marshalling yard etc. These yards, if electrified, should be
electrically independent of each other. Each yard, if it consists of
more than four lines, shall be divided into two or more elementary sections consisting of group of 3 to 4 lines each. Each
elementary section should be fed by an isolator from a bus connected to
the yard interrupter in such a way that interruption to any elementary
section should cause minimum upset to the yard working.
31.0 Numbering of OHE Masts
As the P&T overhead telegraph lines on the 25 kv ac electrified
routes are replaced by under-ground screened cable, the OHE masts are
used to indicate the kilometerage of the track. The mast number is also
used for identification of the section of overhead equipment (OHE) and
the line to which it belongs. There are normally 15 to 18 masts in one
kilometer and each mast is given a number in serial order starting from
kilometer post. The number is scribed in two parts, the kilometer being
shown above the line and the mast serial number below the line. For
example, (70/1) indicates the first mast from the kilometer post No. 70
on the Up line.
31.2 Single line section
In single line section where there is no chance of future doubling,
numbering is done progressively in the direction of increase of
kilometerage, i.e. 70/1, 70/2,etc. In case where doubling is anticipated
in future the system of numbering will be according to para 31.3.
31.3 Double line section
All traction masts on Up track shall be given odd numbers, i.e.
75/1,75/3, 75/5 etc. and that on Down track even numbers as 75/2, 75/4,
75/6,etc. 1 and 2 are the serial number of the masts immediately after
every kilometer post. Numbering is done progressively in the direction
of increase of kilometerage.
31.3.1 Since the OHE masts on Up and Down tracks are normally located
opposite each other, the mast numbers 1 & 2 would be in one line,
and mast numbers 3 & 4 would be in in one line and so on.
31.3.2 In case the spans on the Up and down lines are not equal and the
masts are not in one line, the masts shall be numbered in such a way
that higher serial number does not occur at a lower kilometerage (see
31.4 Multiple section
In multiple track section, suffix 'A' is to be given to the multiple
track mast. For instance, in case of a section consisting of UP main,
DOWN main and up slow and Down slow track, the slow track masts shall be
numbered as 75/1A, 75/3A, etc. for UP slow line and 75/2A.75/4A, etc.
for DOWN slow line. Uprights of portals, erected in multiple track
sections shall be numbered with reference to main line only,
31.5 Numbering of masts of loops and sidings in station yards:
31.5.1 Individual masts .
Single cantilever and double cantilever mast supporting OHEs of tracks
on either side ( umbrella type) for loops and sidings shall bear the
station coda and serial number in one thousands series (1000).The
station code shall be given on above the horizontal line and the serial
number below it. Masts of UP loops and siding on UP line side shall be
given odd number of 1001,1003,1005 etc. In the order of progressive
chainage, irrespective of the n umber of loops and the masts on the DOWN
loops and sidings on*he DOWN line side shall be given even numbers
In case several independent cantilever masts for different loops are
located at the same chainage, loop mast nearest to the main track should
bear the lowest number in the series (see Fig. 10). This system of
numbering is applied from one end of a yard in the kilometerag of the
starting point and progressively higher numbers is given in the
direction of increase in chainage whether it is UP or DOWN yard. The
numbering does not indicate the kilometerage.
31.5.2 (a) In case a portal is provided, the upright of the portal
nearest to the main track shall be given a number in 2000 series, the
other upright of the portal shall be given a number in 3000 series. In
case of 3-leg portals, the farthest leg from the main track shall be
given a number in 4000 series.
31.5.2(b) In case a portal is covering both UP and DOWN main line as
well as loops and siding, the numbering shall be as for the main line tracks, irrespective of the
fact that it also covers loops.
31.5.2 (c) In case of a portal, covering UP main line and a number of UP
side secondary tracks, the upright which is located near the main track
and service the main line shall be numbered with respect to the main
track. Other upright shall be given the same number with suffix 'A'.
31.5.2(d) The uprights of portals in UP yard shall have odd numbers i.e.
2001-3001, 2003-3003 etc. and the uprights in DOWN yard shall have even
numbers i.e. 2002-3002, 2004-3004 etc.
31.6 Head Span mast
Procedure of numbering the mast of a head span shall be the same as that
for portals detailed in 31.5.2 except that the mast of the head span
shall be given numbers in 5000, 6000 and 7000 series as detailed in
31.7 Branch line masts
All masts on branch lines taking off from the main line are to be given
a prefix letter indicative of the branch line mast e.g.
Pradhankanta - Pathardih which takes off from the main line at
Pradhankanta is given a prefix letter 'P' which is indicating of
Pathardih viz. 70/14 P.
31.8 Alternative numbering
Mast on loop/yard lines may also be numbered with a letter/word prefixed
indicating the nomenclature of the line e.g. the mast numbers on a goods
line in passenger station area may be numbered as G1, G2 etc. below the
station code. The mast numbers on engine run-round line may be numbered
as ELI, EL2 etc. This method may be adopted when additional lines are
provided or wired subsequently.
31.9 Switching station masts
Mast at the switching station are numbered with the station code of the
switching station for example KGP/1 which means Kharagpur Switching
Station, mast No.,1.
32.0 Numbering of Equipment
32. 1 Abbreviation of equipments
To identify the location of the equipments covering OHE and Switching
stations a code for identifying the type of equipment followed by a S.
||25 kV/230V Auxiliary Transformers.
||Interruptor for main lines.
||Interruptor for yard lines.
||Bus coupler interruptor.
||Bus coupler isolator.
||Double pole isolators. '
||Single pole Isolator at Switching Station.
||Single pole isolator at substation.
||Isolator for main lines.
||Isolator for secondary lines loops and yards.
32.2 Numbering circuit breakers
Each power transformer, current transformer, potential transformer is
given a serial number in a Railway starting from 01 except 25 kV circuit
breakers which shall be according to para 32.2.2.
32.2.1 High voltage (132/110/66 kV) circuit breakers are given two digit
numbers progressively increasing in the direction of increasing
kilometerage starting from 01. For example, the first high voltage
circuit breaker will be numbered as CB/01, 02, 03.
32.2.2 25 kV circuit breakers are given three digit numbers - odd nos.
e.g. CB/101, 103, 105 etc. for feeder breakers and even nos. CB/100,
102, 104 etc. for transformers circuit breakers.
32.3 The serial number of transformers and circuit breakers also follow
geographical sequence within a substation/feeding post. Lower number is
given for the equipment connecting at less kilometerage and higher
number of for the equipment connected to higher kilometerage.
The main line 25 kV interruptors are numbered serial wise progressively
increasing from a datum point on a railway, e.g. BM/01.02, 03 etc.
32.5 Yard Interruptors. The yard line interruptors are numbered serial
wise on a railway i.e., BS01, 02, 03 etc. Where there are different
yards for up and down direction, the interruptor for UP yard is given
odd number and that for DOWN yard is given even number.
FIG. A 1.21
32.6 Other equipment.
The number of other equipments is serial wise progressively increasing
irrespective of up or down line on a railway preferably according to
32.7 Numbering of elementary section
Elementary section for main line are given a number beginning with the
number of interruptor which feeds it (See Fig. A1.21).
32.7.1 The first two/three digits of the number for an elementary
section indicate the governing interruptor and last two digits indicate
the progressive serial numbers. This progressive serial number for UP
line are odd number starting with 01 for example 3401, 3403 etc. and
even number for DOWN line starting with 02 such as 3502, 3504 etc.
32.7.2 Yard elementary sections.
The elementary section number of yard lines shall be provided with the
number of the isolator which controls the feed of the line/s with a
prefix 'X'. For example, if an isolator, no. 118 controls the feed of
the lines of the receiving yard the elementary section number of the
lines is 'XI18".
32.7.3 Elementary section for two sides
If the line/s are fed by an inter-locked isolator numbering of the
elementary section should corresponds to the isolator number which
normally feeds the line/s.
32.7.4 Type of number plates.
The number plates shall be in accordance with drawing no. RE/33/P/7501.