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DESIGN ASPECTS OF SUBURBAN RAILWAY 
ELECTRIFICATION
A dissertation submitted to the
Department of Electrical Engineering, University of Moratuwa 
In partial fulfilment of the requirements for the 
Degree of Master of Engineering
library
11 DIVERSITY OF MORATUWA, SRI LANKA 
MORATUWA
By
D. M. C. M. K. DASSANAYAKE
University of Moratuwa
87264
Supervised by: Dr. Lanka Udawatta
&£l.3 <3 6
Department of Electrical Engineering 
University of Moratuwa
December 2006
; o q0"
87264
DECLARATION
The work submitted in this dissertation is the result of my own investigation, 
except where otherwise stated.
It has not already been accepted for any degree, and is also not being 
concurrently submitted for any other degree.
D.M.C.M.K. Dassanayake
December 2006
I endorse the declaration by the candidate
Dr. Lanka Udawatta
Abstract
The highway transportation of Sri Lanka is becoming more and more time consuming 
due to road traffic congestion and becoming more expensive due petroleum fuel prices. 
Travelling by highway is a more stress full thing and it creates lots of fatigue on 
passengers. Use full time has to be wasted on the road without any productivity.
As a remedy for this burning issue, railway transportation is to be improved using 
modem technology and techniques. By improving railway transportation lot of direct and 
indirect benefits can be received.
Commuter will receive a comfortable travelling with minimized fatigue hence better 
productivity is the result in return. Reducing wasted man hours on travelling also will 
result to improve the productivity of the country. Properly scheduled train service will 
attract passengers using other modes of transportation. So it will automatically reduce 
the road traffic congestion and considerable amount of fuel can save by minimizing 
vehicles idling. Also it will reduce the road traffic accidents.
By using electrified railway system with regenerating facility big amount of energy can 
be saved without wasting. Alternative fuel such as heavy oil, coal or some times nuclear 
power in the future can be used to generate electricity and hence reduced the dependency 
of petroleum fuel. So long term train fare consistency can be expected.
In the view of environmental protection, electrified railways are the best environmental 
friendly transport mode compared to other modes of transport.
For this study only a part of the main railway line, Colombo - Polgahawela section is 
considered. From all relevant data extracted from railway department statistics, required 
numbers of Electro Motive Units (EMU) are decided and the study lead to financial 
considerations which emphasis the feasibility of the project.
n
Declaration 
Abstract 
Contents 
List of Figures 
List of Tables 
Chapter 1 
CONTENTS 
II 
lll 
vi 
Vll 
1.0 Introduction .J 1 
1.1 Sri Lanka Railway 1 
1.1.1 Railway Expansion Projects 2 
1.2 Organization 5 
1.3 Rolling Stock 5 
1.4 Previous Studies on Railway Electrification 7 
1.5 Scope of the Railway Electrification 7 
1.5.1 The necessity of the Project 7 
1.6 Electric Trains and Electrical Power Supply 
Developments J 0 
Chapter 2 
2.0 Basic Developments of electrified locomotion 12 
2.1 Basics - Volts and Amps 12 
2.2 DC Motors 13 
2.3 Resistance Control and Camshafts 15 
2.4 Transformers .. ~ 15 
2.5 Rectifiers 16 
2.6 Thyristors 16 
2.7 Gate Turn Off (GTO) Thyristor 17 
2.8 Choppers J~ 
2.9 AC Motors ... 19 
2.10 GTO Inverters ~ 20 
2.11 Insulated Gate Bipolar Transistor ·l.~ 2.12 Force Commuted Bridges ':.4... 21 
2.13 Braking Electrified Locomotives 'f 22 .. r 
I 
Chapter 3 
3.0 Electrification Area, Operation and Equipment 23 
111 
3.1 Existing Passenger Flow 24 
3.2 Procedure 25 
3.3 Operating system requirements 25 
3.4 Equipment Costs 25 
3.5 Operating Expenses 26 
3.5.1 Electrical Energy 26 
3.5.2 Maintenance Expenses 27 
Chapter 4 
4.0 Present Railway Operation 28 
4.1 Train Speeds and Speed Restrictions 29 
4.2 Financial Considerations for Past years 29 
4.3 Expected daily one directional passeng_)f flow 30 
Chapter 5 
5.0 Proposed Operating System 31 
5.1 Outline 31 
5.2 Expected passenger volume after Electrification 31 
5.3 Electrical Multiple Units 32 
5.4 Calculation of the Requirement of EMUs 34 
5.5 Railway Track, Signaling and Communication 36 
5.5.1 Railway Track 36 
5.5.2 Signaling system 36 
5.5.3 Catenary (Power Transfer) System 37 
Chapter 6 
6.0 Project Analysis 40 
6.1 Selection of Rolling Stock 
... ' 
40 
6.2 Engineering Calculations .r 42 
6.3.1 Specific Train Resistance 42 
6.3.2 Curve resistance of a train 44 
6.3.3 Calculation of Tractive Effort 45 , 
6.3.4 Torque developed by a traction motor .-"'4'6 
6.3.5 Specific Energy Consumption 47 
6.3.6 Energy returned to the line 47 
6.4 Power Requirement -;..4.. ~-
6.4.1 Energy requirement per kilometer '!' 49 
6.5 The Traction power supply system 49' .. 
6.5.1 Required Power generation Capacity 51 
6.6 The overhead Contact System 52 
6.6.1 Required modifications to accommodate 
the catenary system 53 
lV 
6.6.2 Air gap Clearance 53 
6.6.3 Remote control and Dispatching system 54 
6.6.4 SCADA and it' functions 54 
6. 7 Results of TeclmicaJ Calculation and Capacities 56 
Chapter 7 
7.0 Financial and Economical Appraisal 57 
7.1 Capital cost 57 
7 .1.1 Cost of Electrical Engineering work 57 
7 .1.2 Cost of plant & Machinery for the 
Maintenance department 58 
7.1.3 Procurement of rolling stock j 58 
7.1.4 Cost of Railway track Rehabilitation 58 
7.1.5 Maintenance cost 59 
7 .1.6 Operating cost 59 
7.2 Revenue from Operation 61 
7.2.1 Tariffs 61 
Chapter 8 
8.0 
8.1 
8.2 
Chapter 9 
9.0 
Conclusion 
Advantages of Electrical Engines 
Disadvantages of Electrical Engines 
References .. '..--
.. 
APPENDIX 
Annex I 
Annex 2 
Annex 3 
v 
I 
;A. 
y 
65 
65 
65 
66 
" , . 
·· 67 
70 
... 
/ ... 
List of Figures 
Figure 
1.1 
2.1 
2.2 
2.3 
2.4 
2.5 
2.6 
2.7 
2.8 
5.1 
5.2 
5.3 
5.4 
5.5 
5.6 
5.7 
5.8 
6.1 
6.2 
6.3 
6.4 
6.5 
6.6 
6.7 
Sri Lanka Railway Net work 
A basic electric circuit 
DC and AC wave form patterns 
Schematic Diagram of series connected and separately 
Excited motor 
AC Voltage input with Equivalent DC Level 
Equivalent DC Levels 
Equivalent DC Voltages of Chopper circuits j 
AC Three Phase Waveform · 
Output Waveform of a GTO Inverter 
Motor Car 
Trailer Car 
Formation of an electro motive unit 
Modes of Catenary Systems 
3D View of a catenary system and a Wire Cross section 
Pantograph of a Catenary in Operation 
Inside view of a Crew Cabin 
Inside view of a Trailer Car 
A modem passenger EMU in service 
Front side view of an EMU 
Variation Specific Train Resistance with Velocity 
Overhead Contact System 
Required Modifications 
Parts of an AC Traction Motor 
Monometer Bogie 
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.. 
VI 
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Page 
04 
12 
13 
14 
16 
17 
18 
19 
20 
33 
33 
33 
37 
38 
38 
39 
39 
40 
41 
44 
52 
53 
55 
55 
, 
...,.,. 
,.~ 
/ ... 
List of Tables 
Table 
1.1 
1.2 
1.3 
3.1 
3.2 
3.3 
4.1 
4.2 
4.3 
5.1 
5.2 
6.1 
6.2 
7.1 
7.2 
Railway Network and Distances 
Total No. of Stations of each line 
Locomotive Categories and Purchased years 
Detailed One directional peak hours passenger flow 
Present One directional peak hour passenger flow 
Expected One directional peak hour passenger flow 
Average number of trains and train kilometers 
Summary of loss of Recurrent Expenditure 
Expected one directional passenger flow after 
Electrification 
Expected peak hour one directional passenger flow 
Technical Specifications i 
Specific train Resistance 
No. ofEMU's and Sub station Capacities 
Daily Sectional Average Passenger kilometers 
Cash flow analysis 
.. ~ 
~ 
Vll 
I 
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y 
Page 
1 
2 
6 
23 
24 
24 
29 
29 
30 
32 
32 
43 
56 
62 
63 
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