1. Department of Technical Education
Andhra Pradesh
Name : K.D.V. Narasimha Rao
Designation : Lecturer
Branch : Electrical & Electronics Engineering
Institute : Andhra Polytechnic, Kakinada
Year / Semester : VI Semester
Subject : Electric Traction and PLC
Sub Code : EE605B
Topic : Electric Traction
Duration : Min
Sub-Topic : Train services & speed time curve
Teaching Aids : PPT, Animations
Revised By : D.S.V.S. Prasad,SL/EE,APT,Kakinada
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2. Recap In the last class we have discussed about
Systems of track electrification
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3. Objectives On completion of this period, you would be able to
List the types of services
Sketch the speed-time curves for the above services
Know the importance of speed time curves
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4. Types of Services
Three main types of services are there in Electric Traction
Urban or City Service
Sub-Urban Service
Main-Line Service
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5. Urban or City Services
Distance between two stops is very small (i.e., about 1km)
To achieve the speed schedule
Require high acceleration and high
retardation
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6. Sub Urban Services Distance between two stops is relatively
longer (i.e., about 2km to 3.5km)
To achieve the speed schedule
It also requires high acceleration and
high retardation
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7. Main Line Services
Distance between two stops is long (i.e., more than 10km)
To achieve the speed schedule
Does not require so high acceleration
Does not require so high Retardation
Total running time is more as compared to accelerating
time
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8. Characteristics of Services
S.No
Type of service
Accele-ration
kmphps
Retard-ation
kmphps
Max. Speed
(kmph)
Distance between stops in km 1 2 3
Urban
Sub-Urban
Main Line
1.5 to 4
1.5 to 4
0.6 to 0.8
3 to 4
1.5
120
160 1
2 to 3.5
> 10
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9. Speed - Time Curve
The curve drawn between speed of a Train in kmph along Y-axis and time in seconds on X-axis.
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10. Speed-Time Curve for Main Line Service3 2 4
Speed
kmph 1 5
Fig.1 t1 t2
Time
(second) t3 t4 t5
Notching up or Rheostatic acceleration.
Acceleration on speed curve.
Free running curve
Coasting or coasting retardation curve.
Braking curve.
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11. Speed-Time Curve for Urban Service
kmph
Coasting
Acceleration
Braking
Time in seconds
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12. Speed-Time Curve for Sub-urban Service
kmph
Coasting
Acceleration
Braking
Time in seconds
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13. Summary In this lecture we have discussed about Types of services
How to draw speed-time curves for different types
of train services.
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14. Quiz 1.The distance between two stops in Urban service is 1 km
2 to 3 km
More than 10 km
Less than 5 km
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15. Quiz 2.The distance between two stops in main line service is 2 km
2 to 3 km
More than 10 km
Less than 5 km
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16. Quiz 3.The distance between two stops in Sub-Urban service is a. 1 km
b. 2 to 3.5 km
c. More than 10 km
d. Less than 5 km
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17. Frequently Asked Questions
What is speed – time curve?
What are the types of services?
Sketch the speed-time curves of urban, sub urban services
Distinguish between urban, sub urban and main line services
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18. THANK YOU
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