This report is a master degree thesis in electronics that examines if weak relations can be used in TracFeed. TracFeed is a simulation tool designed to aid in the dimensioning of the power supply
system for electrical railroads. The program was originally developed by Adtranz and is today further enhanced by Balfour Beatty Rail AB.
When using weak relations there will be fewer truncations of the steps and therefore the response time will decrease. The purpose of this thesis is to study how much time that can be gained in
different types of simulations and in which way the result is effected because of weak relations. The theoretical part explains the fundamentals concerning electrical trains and how trains are
modelled in TracFeed. The calculation kernel used by TracFeed is called SIMPOW and it is described as well as the modelling language which is used to create the train models.
Weak relations are tested in two simulations. The result from those simulations shows that if a displacement in simulated time of the output is acceptable and there are many trains active
simultaneously weak relations are an interesting alternative.