EJ2400 Electric Traction 6.0 credits

Elektrisk traktion

The course gives an introduction to electric railway traction including traction mechanics, rail systems, electrical drives, and power supplies.

  • Education cycle

    Second cycle
  • Main field of study

    Electrical Engineering
  • Grading scale

    A, B, C, D, E, FX, F

Course offerings

Spring 19 for programme students

Spring 20 for programme students

Intended learning outcomes

After the examination the student should be able to:

  • describe fundamental system issues in electric railway traction including running resistance, tractive effort, adhesion, power and energy consumption.
  • calculate tractive effort, power, acceleration and velocity of rail vehicles
  • describe different components of an electric traction vehicle and their for traction purposes important characteristics
  • make estimations of voltages, currents and power of electrical drives for rail vehicles with induction motors or dc motors.
  • be familiar with other types of electric drives for rail vehicles,
  • describe the design of ac and dc power supplies for electric traction
  • calculate the power capacity for different railway power supply systems
  • Describe the background to electromagnetic interferences (EMI) in electric railway traction and define important concepts and parameters.

Course main content

Historical survey. General principles of electric traction and traction systems. Tractive and braking effort. Power requirements and energy consumption. Traction vehicles; electric drives, transformers and converters, control and mechanical transmission. Power supply systems; AC and DC supplies, power capacity, overhead catenary systems, overvoltages, line interferences and electromagnetic compability, EMC.


24 h Lecture + 3 Assignments


Bachelor's degree (180 higher education credits), or equivalent qualifications. Documented proficiency in English corresponding to English B/ English 6.

Recommended prerequisites

One of the following courses are recommended; EJ2200 Electrical Machines and Drives, EJ1200 Electric Power Systems or EJ2300 Power Electronics.


Östlund, S., Elektrisk Traktion KTH 2005


  • INL1 - Assignment, 0.5, grading scale: P, F
  • INL2 - Assignment, 0.5, grading scale: P, F
  • INL3 - Assignment, 0.5, grading scale: P, F
  • TENA - Examination, 4.5, grading scale: A, B, C, D, E, FX, F

Offered by

EECS/Electrical Energy Engineering


Stefan Östlund


Stefan Östlund <stefano@kth.se>

Supplementary information

N.B. Courses EJ2400 Electric Traction and EJ2440 Electric Transportation, contain to a certain extent the same material. It is therefore not possible to include both courses for the same degree. A complementary course to EJ2400 Electric Traction can be EJ2410 Hybrid Vehicle Drives.


Course syllabus valid from: Spring 2019.
Examination information valid from: Spring 2019.