History of electric traction in India

 

            Electric  traction  was  introduced  on  Indian  Railways  in  year  1925  on       1.5 KV DC and  the first  electric train ran between Bombay's Victoria Terminus and Kurla along the Harbour Line of CR, on February 3, 1925, a distance of 9.5 miles, flagged  off  the then Governor of Bombay Sir Leslie Orme Wilson.

 

            In the year 1957, Indian Railways decided to adopt 25 kV 50 Hz AC traction based on French Railway (SNCF) technology.

 

The first 25kV AC electrified section was Burdwan-Mughalsarai, completed in 1957, followed by the Tatanagar-Rourkela section on the Howrah-Bombay route. The first actual train run (apart from trial runs) using 25kV AC was on Dec. 15, 1959  on the Kendposi-Rajkharswan section (SER).  Howrah-Gaya was electrified by about 1960 , electrification  till Kanpur on the Howrah-Delhi route was done by about 1972, and the entire Howrah-Delhi route was electrified on Aug. 5, 1976. The Bombay-Delhi (WR) route was electrified by Feb. 1, 1988. The CR route was fully electrified by June 1990.

 

            Considering  the  advantages  of  2 x 25kV AC system , it  was  commissioned between Bina and Katni (CR) on Jan. 16, 1995 as  a  pilot  project. This was later extended  to  Bishrampur. Though  this  system  was  not  proliferated  further  earlier,  it  is  being  planned  for  use  on Dedicated  Freight  Corridors  to take  up  heavier  traffic.

 

History of Electric Locomotives

 

SNo

Class of Loco

Year of Manufacturing

Horse Power

Technology

DC Locomotives

1

WCM1

1954

3170

English Electric

2

WCM2

1956

2810

English Electric

3

WCM3

1957

2460

English Electric

4

WCM4

1960

3290

Hitachi

5

WCM5

1961

3700

CLW

6

WCM6

1996

5000

CLW

7

WCG1

1925

2400

Swiss Loco works

8

WCG2

1970

1640

CLW

AC/DC Locos

9

WCAM1

1975

3640(AC)

2930(DC)

CLW

10

WCAM2

1995

4720(AC)

3780(DC)

CLW

11

WCAM3

1997

5000(AC)

4600(DC)

BHEL

AC Locos

12

WAM1

1959

2870

KM-KRUPP-SFAC

13

WAM2

1960

2790

Mitsubishi

14

WAM3

1964

2790

Mitsubishi

15

WAM4

1970

3640

Mitsubishi

16

WAP1

1980

3760

CLW

17

WAP3

1987

3760

CLW

18

WAP4

1994

5000

CLW

19

WAP5

1993

6000

ABB

20

WAP6

1998

5000

CLW

21

WAP7

2000

6350

CLW

22

WAG1

1963

2900

SNCF

23

WAG2

1964

3180

Hitachi/ Mitsubishi

24

WAG3

1965

3150

Europe

25

WAG4

1966

3150

CLW

26

WAG5

1984

3900

CLW/BHEL

27

WAG6

1987

6000

ASEA

28

WAG7

1992

5000

CLW

29

WAG9

1996

6000

ABB/CLW

30

WAG9H

2006

6000

CLW

 

 

Three phase technology

 

            After reaching a power level of 5000 hp, there was no further scope for up-gradation with minimal inputs in the dc drive locomotives, as the capacity of equipment in the traction chain was fully utilised. Any further up-gradation needed a total new design.  During late 80’s, development took place in developed railways towards three phase induction motor based drives for traction due to the distinct advantages of less maintenance intensiveness in comparison to dc drives. Induction motor drives are also known for extremely effective regeneration, thereby reducing the energy cost.

 

            On 23rd July 1993, through a landmark decision, Indian Railways signed a contract with ABB Transportation (Switzerland) for importing freight and passenger class of locomotives together with transfer of technology agreement for indigenous manufacture. The design was approved by RDSO after many technical interactions, in which, CLW also associated. As ABB did not have much experience in the broad gauge system, they had to customise many aspects of bogies, car body, cab equipment, traction motor etc.

 

            Both WAP5 and WAG9 class have GTO based traction converters and microprocessor based control. This was the first time that CLW handled such high technology locomotives, and it needed a paradigm shift in the management of this technology. The real challenge was posed when the technology was to be absorbed and indigenous production to be done. 11 numbers of passenger locomotives which arrived in 1995-96 were directly put into service after field trials. Rated at 5400 hp, it has a maximum test speed of 180 km/h, which can be increased to 225 km/h by certain modifications in the future. These have been tested successfully upto 180 km/h and speed certificate issued for 160-km/h service speed, even though maximum operational speed today is only 150 km/h

 

            6 freight locomotives of WAG9 class received in 1996 in fully assembled and tested condition were also straightaway put on service after trials. This had a rating of 6000 hp with maximum service speed of 100 km/h, capable of delivering 460kN starting tractive effort.

 

            During the year 2000, after mastering vehicle application software by CLW engineers, a new variant WAP7 was built by adapting the original WAG9 design. WAP7 was intended for passenger operation for service speeds up to 130 km/h, which is the maximum speed of Rajdhani and Shatabdi trains today. WAP7 addresses the high-speed segment very well now. With an output of above 6000 hp, this is the most powerful and preferred locomotive for passenger operation today due to its excellent acceleration, deceleration and energy saving features. WAP5 will, however, address the speeds of 140 km/h and above in future, as I.Rly is already working in this direction. CLW went on to build these three classes of locomotives.

           

            A variant WAG9H with an adhesive weight of 135 tonnes was also developed capable of delivering 52 tonnes starting tractive effort targeting 1 in 150 graded sections. Though this locomotive cleared the oscillation trials, this fleet was not built due to other operational reasons-as a result the prototype WAG-9H (#31030) was converted in to WAG-9 class. However, with increased axle loads now being permitted, Railway Board has placed order for 4 locos of WAG-9H class with 22 tonnes axle load. The first locomotive, viz., 31086 with 22 tonnes axle load was flagged off by Hon’ble MR on 29th July 2006 and has entered in to service.

 

 

Advantages of three phase locos:

 

·        Better relaibilty and availability of three phase locos

·        It regenerates energy about 15-18%, a moving power house. Regeneration of power is available in 3-phase locomotives. Regenerative braking effort is available from the full speed till dead stop. Consequently, the overall efficiency of operation is higher.

·        Maintenance cost of a 3-phase locomotive is less due to absence of brush-gear/ commutator in the traction motors and   switchgears in the power circuit.

·        3-phase locomotive operates at near unity power factor throughout the speed range except at very low speeds.

 

IGBT based propulsion technology

 

            GTO technology is getting obsolete, the world over. IGBT based propulsion system is already in place in a few countries. To tackle the obsolescence problem and keep abreast of the technology and derive its inherent benefits, CLW has already got a project sanctioned for building 5 locomotives with IGBT based propulsion system. This will be according to TCN open standard interface. This is a vision project of Indian Railways presented in Minister’s budget speech 2004-05 and is already underway.  In order to sustain 3-phase technology at affordable cost, and to ensure component level standardisation and obsolescence handling, a parallel development has been taken up with C-DAC (under ministry of IT) for indigenous development of TCN based vehicle control system and IGBT based auxiliary converter.

 

Railway Electrification

 

With a view to reduce dependence on petroleum based energy in Railway transport, IR have been progressively switching over to electric traction. This also enables haulage of heavier loads at higher speeds, thus increasing throughput. It is a pollution free system and with use of modern high horse power locos having regenerative braking, it becomes vastly energy efficient.

 

On IR, Electric traction was first introduced on 3rd Feb.’1925 between Bombay VT to Kurla Harbour line (16 RKM) on 1.5 KV DC system. By March 2008 electrification on IR had extended up to 18145 RKMs. This constitutes 28.65% of the total Railway network and 36.42% of the BG system .

 

Plan period wise progress of electrification

 

Plan Period

RKM Electrified

RKM Cumulative

Pre-Independence 1925-1947

388

388

1st  Plan 1951-56

141

529

2nd  Plan 1956-61

216

745

3rd  Plan

1678

2423

Annual Plan 1966-69

814

3237

4th  Plan 1969-74

954

4190

5th  Plan 1974-78

533

4723

Inter Plan 1978-80

195

4918

6th  Plan 1980-85

1522

6440

7th  Plan 1985-90

2812

9252

Inter Plan 1990-92

1557

10809

8th  Plan 1992-97

2708

13517

9th  Plan 1997-02

2484

16001

10th  Plan 2002-07

1810

17811

11th  Plan  1st year 2007-08

502

18145*

                 2nd year 2008-09 

797

18942

                 3rd year 2009-10 

1117

20059

                                                                                                                                                                     * 168 RKM deducted as MG electrified line dismantled                                                                                                                       

 

AC-DC Convertion work

 

The 1.5kV DC overhead system (negative earth, positive catenary) is used around Bombay (This includes Mumbai CST - Kalyan, Kalyan - Pune, Kalyan - Igatpuri, Mumbai CST - Belapur - Panvel, and Churchgate - Virar).

 

Why Conversion?

 

·        Overhead DC traction power supply system has reached its saturation level.

·        Traction substations inter-spacing being very low making fault level unmanageble and creating serious fire hazard.

·        Investments in DC if continued will be exorritant

·        Very high recurring maintenance cost of DC traction system

 

Work involved

 

OHE modification:

·        Replacement of insulators, section insulators, isolators, increasing  clearances, insulation under bridges & tunnels, insulated overlaps modification, neutral section formation, errection of Aux. transformers, easrthing and bonding as per AC system

·        Construction of AC substations & switching stations including SCADA

·        LT modifications at platforms, washing sidings

 

 

Modifications to Signalling & Telecom:

·        Replacement of AC track circuits with Audio frequency Track Circuits (AFTC)/ Digital Axle counters (DAC)

·        Provision of cut-in relays, screens & earthing

·        Replacement of point motors with AC immunized motors

·        Provision of Optic Fibre Cable (OFC) and STM-1 equipments

Raising /Construction of ROBs & FOBs

 

Benefits of DC-AC conversion

 

·        25 to 30% saving in energy cost due to VVVF drive & Regeneration braking systems being employed in Electric locos & EMUs expected to yield saving of about Rs. 50 Cr/Year

·        Introduction of high power locomotives. WAG7 locos need less maintenance are more reliable and generate higher tractive effort than DC locos. This will result in smoother ghat operation at higher speeds

·        Reduction in Maximum Power Demand for same level of traffic

·        Reduction in no. of substations from 73 to 18 leading to higher reliability & lower maintenance cost

·        Increased life of contact wire

·        Higher voltage insulation level in 25 KV AC system to with stand surged with greater reliability

·        Lesser maintenance on rail bonding in AC sysytem

·        Goods train with 58 BOXN can be taken up the ghat without splitting

·        Utilisation of electric locos will increase.

 

 

Electrification of Sidings

 

            Though all the trunk routes/ Main lines have been electrified 53 no of sidings left out without electrification. This causes unnecessary delay in movement of trains, it is requires traction change etc., Once these sidings gets electrified  loads can reach its destination in time and in turn the turn round period of loads will also get increased.

 

Electrification of Missing Links

 

          Main routes have been electrified and their links are still left out un wired. For example missing links are Jhansi-Kanpur, Itarsi-Jabalpur-Allhabad. These missing links requires to be electrified so that the delay for traction change could be avoided and throughput will get increased with electric loco operation.

 

Train Lighting/Air Conditioning (TL/AC)

         

          Lighting in passenger coaches was introduced starting around 1897. The Jodhpur Railway was the first to make electric lighting standard on all its coaches, in 1902.  A long time ago, steam locos used to have 24V turbine generators to provide power for lighting and other appliances in the coaches. In general, only the first and second class coaches had lights and fans for every compartment, the 'inter' class had only lights, and the third class coaches had just two lights, one at each end near the door. Provision of lights and fans as standard equipment in all compartments was legislated in 1952.

            Individual coaches are powered by axle-driven generators which charge storage batteries that power lights, fans and other electrical fittings. Older coaches have 24V (less often 48V) circuitry and have dynamos connected to the axles by belts. Newer coaches have 110V circuitry and use belt-driven 4.5kW, 110V alternators. Both systems use banks of 24V batteries (mostly lead-acid batteries of an 800Ah capacity) for back-up power. LHB stock uses 4.5kW alternators (6kW for air-conditioned stock). In the 1990s, there was a big push to convert all old stock with 24V systems to the 110V system.

            In older stock, for powering air-conditioning equipment, an inverter was used to convert the DC output of a set of batteries to 415V AC. For some time now, however, groups of 110V alternators delivering 18-22kW each have been used to power air-conditioning equipment (the voltage is stepped up to 415V). Most recently, RDSO has developed a newer 25kW 110V alternator with better power circuitry.

            Many air-conditioned coaches are not self-contained with regard to the power supply. For such coaches, a 'mid-on generator' (MOG) is used; this is a 415V 3-phase alternator (either in one of the coaches or in a separate 'power-car'), the output from which is used both for the air-conditioning, and (stepped down to 110V) for the lights and fans. Some 'end-on generators' (EOG) also generate 415V 3-phase AC.

            Prior to the 1930's, various arrangements for cooling the interiors of passenger coaches existed, mostly for the first-class coaches. The North-Western Railway introduced air-conditioned stock in the late 1930's (the earliest was probably the Frontier Mail in 1936 or 1937). BBCI Railways also experimented with air-conditioning at about the same time. By the early 1950's, air-conditioning was available on several long-distance trains. For example, in 1952-53 there were air-conditioned services between Bombay and Howrah, Delhi and Madras (Grand Trunk Exp.), Bombay and Delhi, Bombay-Amritsar (Frontier Mail), Bombay-Viramgam (Saurashtra Mail), and Bombay-Ahmedabad (Gujarat Mail).  These all used AC units that were mounted beneath the coach body (underslung), interconnected by pipes. Self-contained roof-mounted units appeared in year 1980.

            The first fully air-conditioned train was introduced in 1956 between Howrah and Delhi. Popularly known as the AC Express, it ran on the Grand Chord; later there were two, one running on the Grand Chord and the other on the Main Line. Another train popularly known as the AC Express was the Dakshin Exp. between Madras and New Delhi in the 1960s.

            AC Chair Car stock was introduced around 1955. Until about 1979, air-conditioning was available only in these and in AC First Class cars. Around 1979 the first two-tier AC coaches were introduced. The first 3-tier AC coaches were introduced in 1993 (RCF) and used on the Howrah Rajdhani via Patna. (The first such coach was ER 2301A, later changed to ER 94101A.) The first 60 or so of the three-tier AC coaches had 67 berths each, while all later ones have 64 berths.

Electric Multiple Units (EMU)

          The first 1500V DC EMUs used around Bombay (the first EMUs in India, 1925) were from Cammell Laird (UK) (later Metro Cammell) and Uerdingenwagonfabrik (Germany). Later units were supplied by Breda (Italy) as well.

            IR has electric multiple units in operation in several suburban sections (Mumbai, Chennai, Calcutta, Bandel-Katwa, etc.).  The Mumbai region with 1.5kV DC traction has several models of EMUs, classified from WCU-1 through WCU-15. Most models have DC traction motors with rheostatic control (resistance banks to vary the input power supply). DC EMUs are also used on the Lonavala-Pune section.

            BHEL has recently developed some AC-DC EMUs for use in the Bombay area in both the 25kV AC and 1.5kV DC traction regions. The new AC-DC EMUs also have 3-phase induction motors and thyristor control. Recently  WR has signed a contract with Alstom to convert some of the existing (Jessops) 1.5kV DC EMUs to operate with both AC and DC traction power. The first such rakes are already in regular use in the Borivli-Dahanu section. All the AC-DC coaches have regenerative brakes. The 9xx series rakes fail over to electropneumatic braking directly if regenerative braking does not work, while the 3xx series rakes first fail over to dynamic (rheostatic) brakes first before failing over to the electropneumatic brakes.  The rakes for these will have 12 cars, and the rated max. speed is 100km/h.

            The recent development of the Main-line EMU (MEMU), manufactured by ICF, was intended to address precisely this, to allow EMU operations in more areas. They have a width of 10'8". MEMUs run on 25kV AC power. MEMU driving motorcoaches seat 76 and the trailer coaches seat 108. They have a rated top speed of about 105km/h and are equipped with electro-pneumatic brakes. The trailer coaches weigh about 33.6 tonnes and the motor coaches weigh about 60 tonnes. Earlier versions of MEMUs had a top speed of 60km/h. RDSO improved on these by increasing the horsepower of the traction motors and providing a weak-field arrangement in them for higher speeds.

            During the year 2003, RDSO carried out a series of trials with MEMU rakes carrying 'Dense Crush Loads' ('DCL') stopping at all stations on the Tundla-Kanpur section of NCR. These 4-car MEMUs were provided with a weak-field arrangement. It was seen that the use of the weak field allowed increased acceleration above 40km/h, saving time at 7% at a max. speed of 90km/h and 105 at 100km/h on the 228km stretch.

 

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