mrvc rakes

IMPROVED FEATURES OF NEW DUAL VOLTAGE EMU RAKEFOR MUMBAI SUBURBAN SYSTEM

Dr P.C. Sehgal, Managing DirectorShri A.K. Malhotra, Director (Tech)

ABSTRACT

The changed scenario of urban conglomerates in India has put intensive pressure on the urban transport. Managing urban transport needs becomes even more challenging in a city like Mumbai where the land mass is restricted and the city tends to grow vertically. The transport sector is a significant contributor to air & noise pollution in urban areas and is a significant source of greenhouse gas emission through use of fossil fuels and consequent vehicle emissions. Efficient rail based mass rapid transit systems provide a sustainable urban transport model for large urban areas.

In the last 20 years, there has been a significant development in power electronics leading to use of 3 phase AC propulsion system on Electric Multiple Units (EMUs). With the introduction of Gate Turn-Off (GTO) power switching semiconductors, EMUs with 3 phase asynchronous motors were introduced in the early 90s, which had feature of regenerative braking. This led significant energy saving. The power electronics technology has since developed further and has changed from GTO Thyristor to the IGBT transistor. This new device allows more compact converter designs, lower weight and higher overall power efficiency.

As part of Mumbai Urban Transport Project (MUTP) involving major expansion of Mumbai Suburban Railway System, new technology EMU rakes are being introduced with 3 phase IGBT based propulsion system having regenerative braking. The paper outlines the various technological and passenger friendly features of the new EMUs leading to improve energy efficiency and reduced power consumption and quantifies various benefits arising out of this.

1. INTRODUCTION

1.1 Mumbai Suburban Railway Systems – Overview: th Mumbai is a linear city spread over a distance of 120 Kms. During early part of 20 Century Britishers

realized that to exploit full commercial potential of Mumbai, it would be necessary to provide an electric based Rail transport system in Mumbai for the people to travel. The electric suburban trains were introduced in Mumbai in the year 1925 with 1500V Direct Current traction system. At that time, this was the only modern traction system available any where in the world.

Over the period, the commercial activities in the city of Mumbai continued to increase mainly due to influx of population from neighbouring states to Mumbai which led to over crowding, abnormal increase in population and growth of suburban traffic thus leading to overcrowding in the trains. Suburban transport system operated by two railways Central and Western became the main mode of transport.

The increase in suburban trains in Mumbai did not keep pace with the passenger demand and therefore loading in the existing suburban trains increased. Traveling conditions in trains became unbearable. Above conclusion is supported by the data in table given below.

Mumbai Rail Vikas Corporation

160

International Seminar on Emerging Technologies & Strategies for Energy Management in Railways

TABLE-1

1951-52 1961-62 1971-72 1981-82 1991-92 2001-02 2004-05 % incr-ease fromthe year1951-52

Passenger carried 292 454 915 1459 1795 2275 2314 792.47%(millions)

Average trip length 13.8 14.0 16.5 18.8 22.5 26.9 29.6 214.49%(Kms)

Passenger Kilometers 4031 6365 15123 27392 40462 61195 68362 1695.91%(millions)

No. of trains per day 741 960 1161 1577 1889 2055 2093 182.45 %

Growth in Mumbai Suburban EMU Trains

From the table it is evident that not only the No. of passengers carried per train increased substantially but the average journey length also increased thus multiplying the adverse affect of uncomfortable travel conditions.

161


Design capacity of 1500V DC EMU rake is 900 passengers per coach in sitting and 900 passengers in standing position. The city of Mumbai has witnessed unprecedented population growth and now the population in the city has crossed 15 million. The up gradation of the transport system has not kept pace with the increase in population. Against the capacity of 1800 passengers, during peak period in a 9 car rake, as many as 4500 passengers travel.

Fig. 1 View of an overcrowded Mumbai suburban train

2. MUMBAI URBAN TRANSPORT PROJECT

Rail projects were identified under MUTP through the project preparatory studies with the objective of:

Bringing down the over crowding in peak hour peak direction 9-car train to 3000 passengers as against existing around 5000.

Segregate the suburban train operation from the main line passenger and freight services.

To execute these projects Mumbai Railway Vikas Corporation Ltd. under Ministry of Railways and Govt. of Maharashtra was formed. MUTP (Rail Component) has been bifurcated in two phases (Phase I and Phase II).

2.1 MUTP Phase I

Mumbai Railway Vikas Corporation Ltd is a Special Purpose Vehicle set up jointly by the Ministry of Railways and Govt. of Maharashtra to execute the projects under MUTP. The Phase I of MUTP at a total cost of Rs. 3500 crores is already under execution by MRVC and is targeted for completion by June 2009. The major infrastructural inputs in MUTP Phase I are:

Addition of 93 track Kms – base figure 790 Kms [excluding loop lines and yards] (34 Kms in Thane-Turbhe-Vashi section and 52 Kms in Borivali-Virar section under MUTP have since been added)

Induction of 101 new 9-car rakes – 51 on additional account and 50 on retrofitment account (base figure 191 rakes).

Resettlement & Rehabilitation of 15,857 Project affected households.

Running of 12-car rakes on all lines (excluding Harbour Line) by lengthening of all platforms

?

?

?

?

?

?

162


?

?

?

?

?

?

?

?

?

?

Achieving 3 minutes headway on all the lines (re-spacing of signaling to be done).

DC to AC conversion in all suburban section except Thane-CSTM (taken up in Phase II).

2.2 MUTP Phase II

The works to be taken up in Phase II of MUTP have already been approved by Ministry of Railways and Govt. of Maharashtra at a total cost of Rs. 4500 crores. The funding arrangement and sanction of Phase II is under process.

The major infrastructural inputs in MUTP Phase II are:

Addition of 88 track Kms - existing 790 Kms and 93 Kms being added in MUTP Phase I

96 new 9-car rakes (existing 191 and 51 being added in MUTP Phase I)

DC to AC conversion in Thane-CSTM section (172 Track km), completing the DC-AC conversion on Mumbai Suburban system.

Resettlement & Rehabilitation of 2,839 Project affected households

At the end of Phase II, the crowding in the suburban trains will further come down to around 3,000 passengers per 9-car train in the peak hour peak direction after meeting the additional requirements generated during the interim construction period.

3. IMPROVED FEATURES OF NEW EMU RAKE

3.1 Background:

3.1.1 MRVC is procuring 101 sets (in terms of 9-car) of IGBT based Dual Voltage 3-Phase Propulsion System and associated equipments. These will be fitted on the new EMU coaches to be manufactured at Integral Coach Factory at Chennai with existing design shells and bogies. In addition Ministry of Railway is also procuring rakes under GP-194 project. Total No. of rakes being procured presently are:

EMU PROCUREMENT

Total No. of rakes : 174, 9 car

MRVC contract : 101, 9 car

GP-194 : 56, 9 car

GP-194 (30%) : 17, 9 car

3.1.2 Electrical Equipment will be supplied by M/s. Siemens @ Rs. 8.9 Cr. Per 9-car rake.

3.1.3 EMU Coach Body and Bogie manufacturing, installation, Testing and commissioning of EMU Rake to be done by ICF @ Rs. 10.39 Cr. Per 9-car rake.

3.1.4 Total cost of 9-car EMU Rake with improved feature is @ Rs. 19.3 Cr. as against total Cost of fully imported 9-car rake.

3.1.5 A number of improvements have been done on the exteriors, interiors and furnishings. A 3-car unit with improved features was introduced in service for the purpose of Commuter Preference Survey, to help MRVC in selecting options preferred by Commuters. The improved features have been finalized.

163


Features of EMU Rakes :

3.2.1 Performance Features :

Features MRVC EMUs Existing DC EMU

Acceleration with super densecrush loading 0.54 m/s2 0.36 m/s2

Deceleration 0.76 m/s2 (100 to 50 kmph)0.84 m/s2 (50 to stand stilll) 0.6 m/s2

Max Service Speed 100 kmph 80 kmph

Specific Energy Less than 29 units per Thousand Gross Consumption Ton Km(at a schedule speed of 33 KmpH) 40 KWH/100 GTKM

Traction Motor Power Rating 240 kW 187 kW

Traction Control Microprocessor based control Resistance Control& Fault Diagnostics

Auxiliary Power Supply 115 kW 12 kWCapacity

Passenger Information System Menu Driven Digital Audio –Visual system Normal PA Systemin each coach

3.2.2 Improved Ventilation Systems

3.2.2.1 In the Island city of Mumbai, Sub-urban Railway System operates 2500 EMU trains each of 9 or 12 cars and 6.3 millions passengers commute per day and is considered to be the lifeline of the city. In the morning and evening peak periods loading in each EMU coach is around 500 passengers i.e. 4500 passengers per 9 car train, which is the highest in the world and reflects travel under extreme crowded conditions. During peak period the ventilation, which is practically non- existent is a serious problem faced by the commuters.

Now new EMU trains, each of 12 car being procured under World Bank Funded Mumbai Urban Transport Project, improvement of ventilation has been taken up as a challenge and an opportunity to meet the long pending demand to make the travel comfortable. After designing, manufacturing and extensive field trials, the new Forced Ventilation System has been successfully provided in these trains.

The paper describes complete details of the system.

3.2.2.2 New Forced Ventilation system Concept for MRVC designed EMU rakes

Having tried various piecemeal modifications to mitigate the ever-worsening situation of ventilation and increasing criticism from the traveling public and press, there was a need to think afresh and go back to the drawing board and consult the professionals in the field of ventilation. It was a big challenge to design the new ventilation system, to be sound in theory and meeting the exacting requirements with collection of Data on scientific basis.

164


Mumbai Railway Vikas Corporation (MRVC) planned 129, 12 car EMU rakes with state of the AC traction technology ,having increased power rating of Auxiliary supply .In the new EMU rakes being procured by MRVC under MUTP, ventilation system was included for comfort of passengers. Since earlier improvements / modifications were not successful, MRVC took the initiative to correctly define the specification and get a system that could meet the requirement in totality.

Following actions were taken

3.2.2.3 Data Collection

Portable Co meter capable of indicating and recording Co in ppm level with time 2 2

was procured to following Specifications:-

Range : 0 – 5000 ppm

Features : (a) Digital meter with multilingual user interface

(b) Numerical and graphical display of measurements

(c) Data can be logged and transferred to PC via M170 Link

software

(d) Portable instrument suitable for field checking of Co levels. 2

Extensive field measurements were done in the DC EMU coaches under various passenger load conditions ranging from 100 – 500 persons per coach, it was found that the Co level are generally ranging from 800 ppm - 3600 ppm in empty 2

conditions to peak load.

3.2.2.4 Fresh Air Requirement

Recommended level of Co2

- ANSI/ASHRAE standard 62.1 2004 for ventilation for acceptable Indoor air quality.

This American National Standard (ANSI) is a national voluntary consensus standard developed under the auspices of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

- As per Clause 6.1.3, Ventilation requirements of the ASHRAE standard:

“Human occupants produce carbon dioxide, water vapor, and contaminants including particulars matter, biological aerosols, and volatile organic compounds. Comfort (odor) criteria with respect to human bioeffluents are likely to be satisfied if the ventilation results in indoor Co2

concentrations less than 700 ppm above the outdoor air concentration. “

Oxygen is necessary for metabolism of food to sustain life. Carbon and hydrogen in foods are oxidized to Co2 and H O which are eliminated by the body as waste products. Food can be 2

classified as carbohydrates, fats and proteins, and ratio of carbon to hydrogen in each is somewhat different. The Respiratory Quotient (RQ) is the volumetric ratio of carbon dioxide produced to oxygen consumed. It varies from 0.71 for a diet of 100% protein and 1 for a diet of 100% carbohydrates. A value of RQ = 0.83 applies to a normal diet mix of fat, protein and carbohydrates.

?

?

165


The rate at which the oxygen is consumed and Co is generated depends on the physical 2

activity.

A simple mass balance equation gives the fresh air flow needed to maintain the steady state of Co concentration below a given limit.2

N________Vo = Cs-Co

Where Vo = Out door air flow rate required per person

N = Co generation rate per person.2

Cs = Co concentration inside air2

Co = Co concentration in Outdoor air.2

Passenger Loading per Coach

Seating Capacity 90 Passengers

Normal Standing for Peak 90 Passengers

Total Passengers traveling in SDCL 570 Passengers3As per studies conducted, a person with sedentary activity generates 0.018m /hr. Thus

during super dense crush loading (SDCL) of 570 passengers in a trailer coach, the 3volume of Co generated per hour = 570 x 0.018 = 10 m /hr2

During peak travel periods, inside the coaches Co levels go beyond 700 ppm above the 2

ambient Co levels outside the coaches. The high level of Co levels present inside the 2 2

coaches adds to the discomforts of passengers. In order to improve the comfort levels for passengers, rational for minimum physiological requirements for respiration air as covered in ASHRAE standard were studied and it was decided to limit the Co difference between outside 2

and inside the coaches to 700 ppm.

\ Quantum of Fresh air required:- (Co = 700 ppm), (Cs = 700+700 = 1400 ppm)

N 10 3 ________ ________ Vo = = = 15000 m /hr

-6 Cs-Co 700 x 103Hence on each coach, a fresh air of15000 m /hr is required to be pumped inside the coaches

to maintain a steady state Co concentration in the coach not greater than 700 ppm above 2

outdoor air levels.

The forced air ventilation system on coaches has been provided by providing four blowers mounted outside the coaches, two on each end walls and longitudinal duct with diffusers in the coach ceiling.

In these coaches air conditioning is not provided, as with air conditioning, coach doors have to be closed. Presently in peak period 500 passengers are traveling. With door closing it will have to be limited to meet 250 passengers which is not feasible. With present load of passengers to be commuted with limited infrastructure ie. No. of EMU rakes, train capacity and available signaling system. As such forced air ventilation was provided so that the doors are open and number of passengers per train is not reduced.

? ➩

? ➩

? ➩

166


3.2.2.5 Field Trials and results

After Introduction of Rake with forced ventilation system in Passenger service on th12 Nov 2007, field trials have was conducted using portable Co meter and 2

taking public feedback. Highly satisfactory results have been achieved omparison of coaches without forced ventilation system is given below.

The Co level ranges between 700 – 2450 PPM in DC EMU rakes without 2

ventilation system. (Ambient Co levels range between 680 – 800 PPM)2

In new EMU rakes the Co level ranges between 700 – 1450 PPM. 2

Reduction of 1000 PPM of Co levels from the existing highest levels 2

of 2450 PPM.

One set of Graphical readings for DC and AC/AC rakes are as under:

Fig. 2

Above reduction in Co levels leads to following Relief to passengers:2

Improved comfort level.

Feeling fresh and energetic at the end of long commuting period in the overcrowded condition.

3.2.2.6 Design description

3.2.2.6.1 The design concept of ventilation system for MRVC coaches is illustrated in figure 5,6 :

Fig. 3

?

?

?

?

?

?

167


In all, 22 diffusers have been provided along longitudinal duct in each coach

Fig. 4 Supply air Duct and diffuser Grill

3.2.2.6.2 Basic Design

The following sketches show the basic design for the air distribution system for different type of car types.

Fig. 5 Driving Trailer Car, DTC

Fig. 6 Motor Car, MC

3.2.2.6.2 Mounting arrangement

Each coach is fitted with 2 air handling units. In trailer cars (TC, NDTC), the AHUs are fitted on the outside of the car end walls. Driving trailer cars (DTC) and motor cars (MC) have one AHU fitted on the outside of the end wall, while the 2nd AHU is located in a roof cavity next to the partition wall that separates the passenger compartment from the driver cabin or High Tension equipment compartment.

168


3.2.2.6.3 Supply air duct

The supply air duct is arranged in the coach ceiling area, between both the AHU’s. The duct is equipped with air-diffusers over its length, such that the fresh air is blown near to the existing air circulating fans and in the centralize, resulting in a better mixing with inside air resulting in a more uniform air distribution. The aim is to have coordinated approach such that, fresh air is not only circulated in the aisle i.e. below the duct, but also in the area where passengers are seated. The width of the fresh air duct is 670 mm; the maximum height is approx 290 mm. The resulting cross section area amounts to 0.19m². The air circulation fans are mounted at the interior ceiling.

3.2.2.7 Mock-up Development Phase

To ascertain that a perfect design is evolved, a full coach size mockup was prepared at the manufacturers works and actual functioning was checked and fine tuning of each basic unit right from the blowers speed, capacity grill size direction etc. was perfected before the development of prototype and series protection.

Fig. 7 Mockup of ventilation

3.2.3 Improvements in Exterior, Interior and Furnishings

3.2.3.1 Features of Exterior Colour Scheme

Existing EMU rakes, the external colour scheme is gulf red & pale cream. This has been redesigned by NID, Ahmedabad.

Fig. 10

169


3.2.3.2 Windows and Protection Window screen

The windows in the existing EMU rakes are of size 2’ x 2.5’. In the MRVC coaches, larger windows of size 3’ x 23/4’have been provided. The protective window screen is made of stainless steel. Larger windows will enable standing commuters to have better outside visibility.

Fig. 11

3.2.3.3 Seat Frame

i. The seat frame in the existing coaches is of mild steel. There are cases of seat frame breakages due to overloading and corrosion due to humid and saline climate of Mumbai.

ii. In the MRVC EMU coaches, the seat frames are of stainless steel. New seat frames are strong, will not get corroded and are aesthetically appealing.

iii. Presently the seats in the 2nd class compartments are of compressed wood and in the 1st class of cushioned jute & rexine.

iv. In the MRVC EMU coaches, the seats in the 1st class are P.U. Foam and 2nd class are made of Polycarbonate.

Fig. 12

170


3.2.3.4 Grab Rails

(i) In the existing EMU rakes, 2 rows of Grab rails are provided

(ii) In MRVC coaches, one extra row of Grab rails has been added. Provision of additional grab rail will ensure adequate hand holding for the standing commuters in the coaches.

Fig. 13

3.2.3.5 Hand Holds

The hand holds in the existing rakes are of mild steel. In the MRVC EMU coaches, the hand holds are of polyurethane in one coach and of stainless steel in other two coaches. These will have increased corrosion resistance and mechanical strength. They will also be aesthetically appealing.

Fig. 13

171


3.2.3.6 Doorway & Compartment partition

In the existing EMU rakes, the partitions are made up of mild steel plus Laminated plastic (LP) sheets. In MRVC coaches stainless steel doorway partitions are provided. The compartment partitions are of stainless steel in MRVC coaches. These are not only stronger & corrosion resistant but also aesthetically appealing.

Fig. 14

3.2.3.7 Doorframe & body side door

The material of door frame has been changed from mild steel to stainless steel and the material of body side door has been changed from mild steel to powder coated aluminium. These are stronger, lighter and better looking.

Fig. 15

172


3.2.3.8 Luggage racks

In the existing EMU rakes, overhead luggage racks are made up of mild steel. In MRVC coaches stainless steel luggage racks have been provided which are stronger and aesthetically appealing.

Fig.16

3.2.5.9 Head Code (Destination Board)

In existing EMU rakes, the head code, which indicates the destination, is scrolling type and is of cloth. In the MRVC coach, programmable LED type head code has been provided. This will ensure better readability and visibility to commuters standing on the platforms.

Fig.17

173


3.2.3.10 Secondary Suspension

(i) The secondary suspension in the existing rakes is of coil springs. MRVC coaches are provided with air springs to handle the overloading. The riding quality will also improve with the air springs.

(ii) It will also ensure uniform coach floor height from Rail-level irrespective of loading.

Fig. 18

3.2.4 Reduction in Noise level

Reduction in Noise level due to :

1. Resilient spring mounting of Knor Bremse make Compressor.

2. Use of A.C Fans

Measurements taken on the coaches show following reduction in Noise level.

Location DC Coach AC/DC Coach Ventilators “on”

Inside Motor Coach 94.3 dB 71.5 dB

Inside NDTC 69.9 dB 70.1 dB

Inside DTC 71.0 dB 71.7 dB

4. CONCLUSION

Presently 10, 12 car rakes have been received in Mumbai Suburban System. These rakes are running satisfactorily on Central and Western Railway. The improved features have been highly appreciated by the Commuters specially the Ventilation System. With the total cost of 19.3 Cr. per rake the new technology EMU rakes have proved to be a big success.

****

?

?

174


mrvc rakes

Documents

Transcript of mrvc rakes