Diesel Traction - 1912
The diesel engine was invented in the year 1893, by a young
German Engineer, called Rudolf Diesel. But it was only nineteen
years later, that the first Diesel locomotive came into existence.
Since then, diesel traction has grown from strength to strength. Over 89,000 Diesel
locomotives have been built in the world so far, the General Motors, USA alone
contributing to as many as 56,000 Locomotives.
Electric Traction - 1881
After many decades of satisfactory performance, the steam
engines were to give way to more modern locomotives. The year
1881 saw the birth of the first electric Railway run by a German
Engineer Werner Van Siemens using both the rails to carry the
current. Finding this a little too dangerous, Siemens soon adopted
the overhead electric wires. Electric locomotives today ran on Rail
roads in many countries.
PURPOSE OF RAILWAY ELECTRIFICATION
• The contact lines permit almost unlimited power at the disposal of the electrically
driven vehicle.
• Permits heavier trains to achieve higher speeds.
• Electric Multiple Units provide fast commuter services with quick reversal at with
main line trains
• Electric Multiple Units offer least interference to the latter due to the EMU’s high
acceleration rates.
• Economy in operation and maintenance
• Saving in consumption of scarce diesel oil and increased through put of traffic.
• The capital cost for provision of fixed installation required for electric traction is
found adequately remunerative for routes having high levels of traffic.
Period Route Kms. Electrified
Prior to Independence (1925-1947) 388
I Five Year Plan (1951-56) 141
II Five Year Plan (1956-61) 216
III Five Year Plan (1961-66) 1678
Annual Plan (1966-69 814
IV Five Year Plan (1969-74) 953
V Five Year Plan (1974-78) 533
Inter Plan (1978-80) 195
VI Five Year Plan (1980-85) 1522
VII Five Year Plan (1985-90) 2812
Annual Plan (1990-92) 1557
VIII Five Year Plan (1992-97) 2708
IX Five Year Plan (1997-2002) 2484
X Five Year Plan (2002-07) 1810
XI Five Year Plan First Year (2007-08) * 502
XI Five Year Plan Second Year (2008-09) 797
XI Five Year Plan Third Year (2009-10) 1117
Total as on 31.03.2010 20059
ELECTRIFICATION
• INDIAN RAILWAYS TOTAL TRACK = 63327 RKM
• ELECTRIFIED upto 31.3.2009 = 18942 RKM
• % ELECTRIFIED = 29.85%
• COST OF ELECTRIFICATION
The approximate average cost of electrification is as under :
PER RKM DOUBLE LINE
For 25 KV AC TRACTION 1 crore 75 lakh
For 2X25 KV AC TRACTION 94 lakh
DETAILS OF ELECTRIFICATION
• Total RKM energized on 1500 V DC = BG 258
• Total RKM energized on 25 KV AC = BG 18942
• Total RKM energized on 2X25 KV AC = BG 627
• Electrification work in progress (Dec 09) = 1000 RKM
• Target for Rly. Electrification during year 2009-10 = 1000 RKM
• Passenger Train KM Hauled by Electric Traction = 49%
• BG Freight GoodsTrain KM Hauled by Electric Traction = 63%
ONGOING PROJECT
• Notification of Award No & Date
IFB No, RVNL/CPM/MAS/VLDE-MPA-DG/OT-4 dated 24/01/2012
• Description of Item/Work
Execution of Doubling of track between Villupuram and Dindigul, for the contract
Package-1-“Construction of Roadbed, bridges, supply of ballast, Installation of
track (excluding supply of rails & PSC sleepers), Electrical (Railway Electrification
and General Electrification), outdoor signalling and telecommunication works for
Doubling of track between Valadi and Manaparai in Tiruchchirappalli and Madurai
Divisions of Southern Railway, TamilNadu, India.”
-58km stretch-
• Contract No & Date
LOANo.RVNL/CPMMAS/VLDE-MPA-DG/OT-4/Package 1 dated 22.10.2012
• Contractor's Name
M/s L&T Construction Infrastructure
Mount Poonamallee Road
PB No. 979
Chennai - 600 089
• Total Tender Cost (for Engg./Elect./S&T)
Rs.157,53,91,274
Double track
• A double-track railway usually involves running one track in each direction,
compared to a single-track railway where trains in both directions share
the same track.
• Double-track railways, especially older ones, may use each track exclusively
in one direction. This arrangement simplifies the signalling systems,
especially where the signalling is mechanical.
• Where the signals and points or rail switches are power-operated, it can be
worthwhile to signal each line in both directions, so that the double line
becomes a pair of single lines. This allows trains to use one track where the
other track is out of service due to track maintenance work, or a train
failure, or for a fast train to overtake a slow train.
PRINCIPAL PARTS OF CONSTRUCTION
PRINCIPAL PARTS OF CONSTRUCTION
• Over Head equipment (OHE)
A system of conductors / equipments carrying traction power from traction
sub station to electric locomotive.
As a standard practice, an independent mast is used to support the OHE for
each track to obtain mechanical independence.
• Independent Mast
Steel masts are of Four types i.e., BFB (Broad Flanged Beam), RSJ (Rolled
Steel Joist) and fabricated rectangular sectional mast of K and B type.
Portals are also used to serve multiple track section where space between
two tracks to locate an independent mast is not adequate.
PRINCIPAL PARTS OF CONSTRUCTION
• concrete foundation
Traction Mast / Portals are embedded in the concrete foundation. There are
different type of foundations which are used according to soil pressure and
location. The five standard types of foundations mostly used are :
(a) Side Bearing (b) Side gravity (c) New Pure gravity (d)Wet
Black cotton soil (e) Dry Black Cotton soil
• Traction Sub Station (TSS)
Every TSS has 2 nos. traction transformer out of which one is working at a
time and the second transformer is stand by. The capacity of each traction
transformer is sufficient to feed its own feed zone and half of the adjoining
feed zone.
• Signalling and Telecommunication (S&T)
Over Head equipment (OHE)
Neutral Section (NS)
RAILWAY ELECTRIFICATION WORKS
• Main works
1 Provision of most economic reliable electric contact system to continuously
supply power to the moving electric rolling stock.
2. Power Supply Arrangements.
3. Provision of switches to regulate the flow of power along with the electric
protective gear.
4. Monitoring and remote control of power supply.
5. Immunization of signalling and the trackside telecommunication circuits
against electromagnetic and electrostatic induction effects of 25 KV, 50 HZ,
single phase traction power supply.
6. Modernization of signalling and telecommunication.
7. Provision of maintenance and operation facilities for electric traction.
RAILWAY ELECTRIFICATION WORKS
• Discipline wise Division of Works
a) Electrical
b) Signal and Telecommunications
c) Civil Engineering
Coordination of Works
• Railway Electrification, being a multi-disciplinary project work, needs
close coordination amongst electrical, signalling &
telecommunications and civil engineering disciplines. It further needs
coordination with outside agencies such as Power Supply Authorities,
the Department of Telecommunications, the Revenue officials as well
as with the Open Line organization or whose section the work is to be
taken up. Accordingly the organization for Railway electrification
coordinates works of all the disciplines and the agencies from
inception to completion including support services to the open line in
early stages of electric traction over the section.
19
SIGNALLING-SPACE INTERVAL METHOD
20
TRACK CIRCUITED OVERLAP
21
22
SIGNALLING AT POINTS
SAFETY IN ELETRIFICATION OF RAILWAYS
• SAFETY PRECAUTIONS ON ELECTRIFIED SECTIONS
• Crane Working
• Track-Circuited Rails
• Care in Handling Pipes
• Street Measuring Tapes not to be used
• Traction Structure Foundation
The top of foundation block of track structures shall be kept clear of all
materials and kept dry.
While excavating, the foundations not be exposed and there should be no
risk of sinking of the foundations.
COST ESTIMATION
• At the planning level strategic decisions are developed that determine
the likely benefits and costs of a project, before further resources are
utilized for more in-depth investigation. At the project level actual
location specific studies are conducted to determine the overall costs
of the project.
• CPM estimation methodology is used at the planning level
CPM estimation methodology components
1. The right of way the track is built upon (ROW)
2. The design and construction of the railway (Design & Build)
3. Raw materials and finished goods required (Materials)
4. Train control and communications systems (C&S)
5. Catenary/grid components for electrified service (if applicable) (Electric
Infrastructure)
Components influenced by factors
• Construction (adding to existing, building new, or upgrading existing
railways)
• Service (passenger, freight, or mixed use)
• Speed (maximum intended speed: 79, 110, 125, 150, or 220mph)
• Motive power (electric or non-electric)
• Trackage (single, double, or other)
• Terrain (plains, hills, or mountains)
• Land Use (urban, suburban, or rural)
CPM components and corresponding
influencing factors
CPM ADJUSTMENT FACTORS
• The five CPM component cost categories have been designated as
“Design & Build”, “ROW”, “Materials”, “C&S”, and “Electric
Infrastructure”. Each cost is based on a finished project, proposed
project, or study cost. Since most of the cost sources pertained to a
particular project.
• To achieve this, the US Army Corps of Engineers “Civil Works
Construction Cost Index System (CWCCIS)” was applied. The index is
used to “…escalate or inflate various project cost features to current
or future price levels…” along with adjusting for the influence of a
project on construction costs.
CPM ADJUSTMENT FACTORS
Base Cost without influence = (2 – State Adjustment Factor) x (State
Influenced Cost)
SCENARIO CPM Methodology
• Scenario CPM = (Design & Build base cost x TE x LU x SP x TR x UP x AD)+ (ROW base cost
x TE x LU x SP x TR)
+ (Materials base cost x TR)
+ (C&S base cost x TR)
+ (Electric Infrastructure base cost x TR)
• Where:
• TE = Terrain multiplier
• LU = Land Use multiplier
• SP = Speed multiplier
• TR = Track multiplier
• UP = Upgrade multiplier
• AD = Additional multiplier
References
Indian Railway Year Book 2002-2003
U.S. Army Corps of Engineers, 2000
Transportation Research Board, 2000
• White, Thomas. 2000. Developing The Pacific Northwest Rail Corridor Incremental Plan. [Online]
• 2000. [Cited: September 29, 2011.]
• http://www.halcyon.com/tawhite/Trans/PNWRC%20INCREMENTAL%20PLAN.htm.
• Whitford, R. K. 1981. Railroad Electrification. An Alternative for Petroleum Savings.
Transportation
• Research Record. 1981, 802.
• a planning methodology for railway construction
• cost estimation in north america
• Jeffrey Tyler Von Brown

Railway electrification

  • 1.
    Diesel Traction -1912 The diesel engine was invented in the year 1893, by a young German Engineer, called Rudolf Diesel. But it was only nineteen years later, that the first Diesel locomotive came into existence. Since then, diesel traction has grown from strength to strength. Over 89,000 Diesel locomotives have been built in the world so far, the General Motors, USA alone contributing to as many as 56,000 Locomotives.
  • 2.
    Electric Traction -1881 After many decades of satisfactory performance, the steam engines were to give way to more modern locomotives. The year 1881 saw the birth of the first electric Railway run by a German Engineer Werner Van Siemens using both the rails to carry the current. Finding this a little too dangerous, Siemens soon adopted the overhead electric wires. Electric locomotives today ran on Rail roads in many countries.
  • 3.
    PURPOSE OF RAILWAYELECTRIFICATION • The contact lines permit almost unlimited power at the disposal of the electrically driven vehicle. • Permits heavier trains to achieve higher speeds. • Electric Multiple Units provide fast commuter services with quick reversal at with main line trains • Electric Multiple Units offer least interference to the latter due to the EMU’s high acceleration rates. • Economy in operation and maintenance • Saving in consumption of scarce diesel oil and increased through put of traffic. • The capital cost for provision of fixed installation required for electric traction is found adequately remunerative for routes having high levels of traffic.
  • 4.
    Period Route Kms.Electrified Prior to Independence (1925-1947) 388 I Five Year Plan (1951-56) 141 II Five Year Plan (1956-61) 216 III Five Year Plan (1961-66) 1678 Annual Plan (1966-69 814 IV Five Year Plan (1969-74) 953 V Five Year Plan (1974-78) 533 Inter Plan (1978-80) 195 VI Five Year Plan (1980-85) 1522 VII Five Year Plan (1985-90) 2812 Annual Plan (1990-92) 1557 VIII Five Year Plan (1992-97) 2708 IX Five Year Plan (1997-2002) 2484 X Five Year Plan (2002-07) 1810 XI Five Year Plan First Year (2007-08) * 502 XI Five Year Plan Second Year (2008-09) 797 XI Five Year Plan Third Year (2009-10) 1117 Total as on 31.03.2010 20059
  • 5.
    ELECTRIFICATION • INDIAN RAILWAYSTOTAL TRACK = 63327 RKM • ELECTRIFIED upto 31.3.2009 = 18942 RKM • % ELECTRIFIED = 29.85% • COST OF ELECTRIFICATION The approximate average cost of electrification is as under : PER RKM DOUBLE LINE For 25 KV AC TRACTION 1 crore 75 lakh For 2X25 KV AC TRACTION 94 lakh
  • 6.
    DETAILS OF ELECTRIFICATION •Total RKM energized on 1500 V DC = BG 258 • Total RKM energized on 25 KV AC = BG 18942 • Total RKM energized on 2X25 KV AC = BG 627 • Electrification work in progress (Dec 09) = 1000 RKM • Target for Rly. Electrification during year 2009-10 = 1000 RKM • Passenger Train KM Hauled by Electric Traction = 49% • BG Freight GoodsTrain KM Hauled by Electric Traction = 63%
  • 8.
    ONGOING PROJECT • Notificationof Award No & Date IFB No, RVNL/CPM/MAS/VLDE-MPA-DG/OT-4 dated 24/01/2012 • Description of Item/Work Execution of Doubling of track between Villupuram and Dindigul, for the contract Package-1-“Construction of Roadbed, bridges, supply of ballast, Installation of track (excluding supply of rails & PSC sleepers), Electrical (Railway Electrification and General Electrification), outdoor signalling and telecommunication works for Doubling of track between Valadi and Manaparai in Tiruchchirappalli and Madurai Divisions of Southern Railway, TamilNadu, India.” -58km stretch-
  • 9.
    • Contract No& Date LOANo.RVNL/CPMMAS/VLDE-MPA-DG/OT-4/Package 1 dated 22.10.2012 • Contractor's Name M/s L&T Construction Infrastructure Mount Poonamallee Road PB No. 979 Chennai - 600 089 • Total Tender Cost (for Engg./Elect./S&T) Rs.157,53,91,274
  • 10.
    Double track • Adouble-track railway usually involves running one track in each direction, compared to a single-track railway where trains in both directions share the same track. • Double-track railways, especially older ones, may use each track exclusively in one direction. This arrangement simplifies the signalling systems, especially where the signalling is mechanical. • Where the signals and points or rail switches are power-operated, it can be worthwhile to signal each line in both directions, so that the double line becomes a pair of single lines. This allows trains to use one track where the other track is out of service due to track maintenance work, or a train failure, or for a fast train to overtake a slow train.
  • 11.
    PRINCIPAL PARTS OFCONSTRUCTION
  • 12.
    PRINCIPAL PARTS OFCONSTRUCTION • Over Head equipment (OHE) A system of conductors / equipments carrying traction power from traction sub station to electric locomotive. As a standard practice, an independent mast is used to support the OHE for each track to obtain mechanical independence. • Independent Mast Steel masts are of Four types i.e., BFB (Broad Flanged Beam), RSJ (Rolled Steel Joist) and fabricated rectangular sectional mast of K and B type. Portals are also used to serve multiple track section where space between two tracks to locate an independent mast is not adequate.
  • 13.
    PRINCIPAL PARTS OFCONSTRUCTION • concrete foundation Traction Mast / Portals are embedded in the concrete foundation. There are different type of foundations which are used according to soil pressure and location. The five standard types of foundations mostly used are : (a) Side Bearing (b) Side gravity (c) New Pure gravity (d)Wet Black cotton soil (e) Dry Black Cotton soil • Traction Sub Station (TSS) Every TSS has 2 nos. traction transformer out of which one is working at a time and the second transformer is stand by. The capacity of each traction transformer is sufficient to feed its own feed zone and half of the adjoining feed zone. • Signalling and Telecommunication (S&T)
  • 14.
  • 15.
  • 16.
    RAILWAY ELECTRIFICATION WORKS •Main works 1 Provision of most economic reliable electric contact system to continuously supply power to the moving electric rolling stock. 2. Power Supply Arrangements. 3. Provision of switches to regulate the flow of power along with the electric protective gear. 4. Monitoring and remote control of power supply. 5. Immunization of signalling and the trackside telecommunication circuits against electromagnetic and electrostatic induction effects of 25 KV, 50 HZ, single phase traction power supply. 6. Modernization of signalling and telecommunication. 7. Provision of maintenance and operation facilities for electric traction.
  • 17.
    RAILWAY ELECTRIFICATION WORKS •Discipline wise Division of Works a) Electrical b) Signal and Telecommunications c) Civil Engineering
  • 18.
    Coordination of Works •Railway Electrification, being a multi-disciplinary project work, needs close coordination amongst electrical, signalling & telecommunications and civil engineering disciplines. It further needs coordination with outside agencies such as Power Supply Authorities, the Department of Telecommunications, the Revenue officials as well as with the Open Line organization or whose section the work is to be taken up. Accordingly the organization for Railway electrification coordinates works of all the disciplines and the agencies from inception to completion including support services to the open line in early stages of electric traction over the section.
  • 19.
  • 20.
  • 21.
  • 22.
  • 23.
  • 24.
    SAFETY IN ELETRIFICATIONOF RAILWAYS • SAFETY PRECAUTIONS ON ELECTRIFIED SECTIONS • Crane Working • Track-Circuited Rails • Care in Handling Pipes • Street Measuring Tapes not to be used • Traction Structure Foundation The top of foundation block of track structures shall be kept clear of all materials and kept dry. While excavating, the foundations not be exposed and there should be no risk of sinking of the foundations.
  • 25.
    COST ESTIMATION • Atthe planning level strategic decisions are developed that determine the likely benefits and costs of a project, before further resources are utilized for more in-depth investigation. At the project level actual location specific studies are conducted to determine the overall costs of the project. • CPM estimation methodology is used at the planning level
  • 26.
    CPM estimation methodologycomponents 1. The right of way the track is built upon (ROW) 2. The design and construction of the railway (Design & Build) 3. Raw materials and finished goods required (Materials) 4. Train control and communications systems (C&S) 5. Catenary/grid components for electrified service (if applicable) (Electric Infrastructure)
  • 27.
    Components influenced byfactors • Construction (adding to existing, building new, or upgrading existing railways) • Service (passenger, freight, or mixed use) • Speed (maximum intended speed: 79, 110, 125, 150, or 220mph) • Motive power (electric or non-electric) • Trackage (single, double, or other) • Terrain (plains, hills, or mountains) • Land Use (urban, suburban, or rural)
  • 28.
    CPM components andcorresponding influencing factors
  • 29.
    CPM ADJUSTMENT FACTORS •The five CPM component cost categories have been designated as “Design & Build”, “ROW”, “Materials”, “C&S”, and “Electric Infrastructure”. Each cost is based on a finished project, proposed project, or study cost. Since most of the cost sources pertained to a particular project. • To achieve this, the US Army Corps of Engineers “Civil Works Construction Cost Index System (CWCCIS)” was applied. The index is used to “…escalate or inflate various project cost features to current or future price levels…” along with adjusting for the influence of a project on construction costs.
  • 30.
    CPM ADJUSTMENT FACTORS BaseCost without influence = (2 – State Adjustment Factor) x (State Influenced Cost)
  • 31.
    SCENARIO CPM Methodology •Scenario CPM = (Design & Build base cost x TE x LU x SP x TR x UP x AD)+ (ROW base cost x TE x LU x SP x TR) + (Materials base cost x TR) + (C&S base cost x TR) + (Electric Infrastructure base cost x TR) • Where: • TE = Terrain multiplier • LU = Land Use multiplier • SP = Speed multiplier • TR = Track multiplier • UP = Upgrade multiplier • AD = Additional multiplier
  • 32.
    References Indian Railway YearBook 2002-2003 U.S. Army Corps of Engineers, 2000 Transportation Research Board, 2000 • White, Thomas. 2000. Developing The Pacific Northwest Rail Corridor Incremental Plan. [Online] • 2000. [Cited: September 29, 2011.] • http://www.halcyon.com/tawhite/Trans/PNWRC%20INCREMENTAL%20PLAN.htm. • Whitford, R. K. 1981. Railroad Electrification. An Alternative for Petroleum Savings. Transportation • Research Record. 1981, 802. • a planning methodology for railway construction • cost estimation in north america • Jeffrey Tyler Von Brown

Editor's Notes

  • #13 A simple polygonal type of overhead equipment is comprising of a single 65 sq. mm. size Catenary wire of Cadmium Copper and a hard drawn grooved copper Contact wire of 107 sq. mm. size suspended from the Catenary by 5 mm dia copper dropper wire spaced 9 meters apart. The OHE is supported by swiveling type Cantilever bracket assembly. A tension of 1000 kgs is given in each conductors i.e., Catenary and Contact wire. This tension is kept constant, automatically compensating the variations in conductor length due to change in temperature through the regulating equipment erected at the termination of conductors, also known as Automatic Tensioning Device.
  • #15 The Catenary wire comprises of 19 strands of cadmium copper, each strand of 2.10 mm dia, with overall dia of 10.5 mm having about 80% conductivity and 65 sq. mm cross-sectional area. The contact wire is a solid hard drawn grooved electrolytic copper of 12.24 mm dia and 107 sq. mm cross-sectional area. Total current carrying capacity of both wires is 600 Amps. The condemning size of contact wire is 8.25 mm.
  • #16 Feeding Post (FP) Feed Length Neutral Section (NS) To separate OHE of two adjoining feed posts. A short neutral section (PTFE) type is provided opposite the Traction Sub Station to avoid the need of lowering the pantograph during extended feed conditions. Sectioning Post (SP) To facilitate the extension of traction power from one feed zone to half of the adjoining feed zone during emergency Sector The section of the OHE between the FP & SP is called the sector
  • #18 a) Electrical Provision of Overhead Equipment, booster transformers and return conductor. ii) Provision of Power Supply Equipment, transmission lines, traction substations, and installation of Power Supply Control Posts. iii) Remote Control of the Power Supply Equipment. b) Signal and Telecommunications: i) Provision of colour light signals and immunization of the signalling installation against induction effects of 25 kV ac traction power supply system. ii) Provision of underground cables for the Railway’s telecommunication lines and provision of additional traction control circuits. iii) Liaising with the Department of Telecommunications for modification of their circuits to immunize them against induced voltages due to traction current. c) Civil Engineering: i) Yard remodeling, slewing of tracks, sidings and oil track works. ii) Construction of loco sheds, service buildings and staff quarters. iii) Modification to overline structures such as overbridges, flyovers, through girder bridges, as well as to tunnels, platform shelters and water columns to suit 25 kV ac clearances.
  • #20 Types of Signalling Systems in Railways Time Interval Method Trains are Spaced Over an length of a track in such a way that , if the first train stops, the following train driver should be able to stop the train in sufficient distance without colliding with the first one. This type is used where traffic is less and weight of the trains are less, e.g: Trams This Type of System cannot be used in Passenger rails since weight and traffic is High Space Interval Method In this method of “Control Over Movement”, the length of the track is divided in to sections called Blocks. The Entry of a train in to the ‘Block’ is controlled in such a way that only when it is free, a train can be allowed to enter it. This means that between two consecutive trains , there is definite space interval.
  • #21 Types of Signalling Systems in Railways Time Interval Method Trains are Spaced Over an length of a track in such a way that , if the first train stops, the following train driver should be able to stop the train in sufficient distance without colliding with the first one. This type is used where traffic is less and weight of the trains are less, e.g: Trams This Type of System cannot be used in Passenger rails since weight and traffic is High Space Interval Method In this method of “Control Over Movement”, the length of the track is divided in to sections called Blocks. The Entry of a train in to the ‘Block’ is controlled in such a way that only when it is free, a train can be allowed to enter it. This means that between two consecutive trains , there is definite space interval.
  • #22 Although it is protected by Signal A123 showing red, the driver of Train 2 may see the green signal A121 behind Train 1 and could "read through" or be confused under the "stop and proceed" rule.
  • #23 Track circuits work by running a circuit using the rails to connect a power source at one end of the block with a relay at the far end. The relay and power source are connected to each rail by cables. As long as the circuit is complete, low voltage power flows down one rail, through a relay, and returns to the power source via the other rail. If the circuit is complete, the relay will be energized, which keeps signals in the "clear" position. If the circuit is broken, the system fails in a safe manner. A broken rail or a failed power source causes the relay to become de-energized and report the section of track as occupied. An unoccupied track circuit is shown in diagram "A". The power source is located at the number "1", with the relay shown at number "2". The completed circuit is shown in green on the diagram. A train is detected because it shorts the circuit. In railroading, this is called "shunting" the circuit. When a train enters a block, the metal wheels and axle conduct the circuit as a short cut which bypasses the relay. This de-energizes the relay, which causes signals to report the block as occupied. This is reflected in diagram "B": "1" shows the power source, "3" is the wheel/axle of a train, and "4" is the de-energized relay.
  • #25 a) Electro-static which result from the high potential of 25 kV on the OHE system. b) Electro-magnetic which is proportional to the currents passing from the sub-station to the OHE to the locomotives/EMUs and back partly through the track and partly through the earth. Such inductive effects occur on large metallic structures such as fencings, structural steelwork of platforms running parallel to the track. They will therefore have to be earthed suitably to afford safety. In track-circulated areas where the rail/s has/have insulated joints, such points shall not be bridged with bare hands or any metallic article. Similarly simultaneously contact with an insulated section of rail/s and non-insulated section of rail/s of the same or other tracks shall be avoided. Use of rails as a foot path, a seat or for such other purposes is strictly prohibited. Particular care shall be taken when carrying or handling long pipes, poles, ladders, over hanging on the shoulder or otherwise to avoid all possibility of such objects and work pieces coming inadvertently in contact with or within 2 m of live equipment. In electrified tracks, steel tape or metallic tape or tape with woven metal reinforcement should not be used.
  • #31 1) The costs associated with a double-track construction would be 1.5 times the costs of a single-track project in the same location. This assumption was made since the existing grade, geometry, and structures offer existing work and economies of scale to be built alongside of. 2)CPM increases by 1.1 from rural to suburban and 1.2 from rural to urban areas. This assumption represents the increased presence of intersections and structures that affect optimal railway placement. While the number of intersections will increase with more densely populated areas, it was determined that a less obtrusive railway would accordingly be built to avoid unnecessary interactions with surface traffic or built-up areas. For central business districts, no multiplier has been included due to the small proportion that this land use represents of the whole. In addition, some projects may utilize current conventional rail infrastructure for built-up areas, therefore cost estimation was deemed too variable to determine. 3)CPM increases by 1.5 from plains to hills and 1.5 from hills to mountains. This assumption was made as the slope, length of slope, maximum curvature, and additional structures encountered result in greater engineering work to Design & Build the railway. This information is based on the effect of terrain on passenger car equivalents for truck traffic with regards to highway capacity. 4) The cost to upgrade a railway is one-third of the corresponding cost to build. This assumption was made as all or a portion of the grade, structures, and necessary geometry is already in place, requiring adaptation or partial building, rather than complete rebuilding.