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EJ2400 Electric Traction 6.0 credits

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

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Headings with content from the Course syllabus EJ2400 (Spring 2020–) are denoted with an asterisk ( )

Content and learning outcomes

Course contents

Historical overview. General principles of electric traction and in particular electric railway 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 interference and electromagnetic compability, EMC.

Intended learning outcomes

Students should after course can:

  • account for fundamental issues in electric railway traction including runninig resistance, tractive effort, adhesion, power and energy consumption,
  • calculate tractive effort, power, acceleration and velocity of rail vehicles,
  • describe the components in electric drives with induction motors and dc motors,
  • make estimations of voltages, currents and power in the electric drives for rail vehicles with induction motors and 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 of electromagnetic interferences (EMI) in electric railway traction and give an account of important concepts and parameters.

Course disposition

No information inserted

Literature and preparations

Specific prerequisites

Degree of Bachelor (180 credits) or the equivalent. Documented skills in English equivalent 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.


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Examination and completion

If the course is discontinued, students may request to be examined during the following two academic years.

Grading scale

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


  • TEN2 - Home assignments and written exam, 6.0 credits, grading scale: A, B, C, D, E, FX, F

Based on recommendation from KTH’s coordinator for disabilities, the examiner will decide how to adapt an examination for students with documented disability.

The examiner may apply another examination format when re-examining individual students.

Opportunity to complete the requirements via supplementary examination

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Opportunity to raise an approved grade via renewed examination

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Ethical approach

  • All members of a group are responsible for the group's work.
  • In any assessment, every student shall honestly disclose any help received and sources used.
  • In an oral assessment, every student shall be able to present and answer questions about the entire assignment and solution.

Further information

Course web

Further information about the course can be found on the Course web at the link below. Information on the Course web will later be moved to this site.

Course web EJ2400

Offered by

Main field of study

Electrical Engineering

Education cycle

Second cycle

Add-on studies

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Stefan Östlund

Transitional regulations

All earlier test parts are now included in TEN2.

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.

In this course, the EECS code of honor applies, see: