As a result of the temperature variation the stresses in continuously welded rails (CWR) can be very large. The high rail temperature causes an increase in the compression stresses, which in combination with the low lateral resistance of the track can lead to rail buckling. On the other hand the low temperature leads to an increase in tension stresses in the rails, which can cause rail breakage. That is why in order to minimise the effect of the temperature stresses the rails are usually installed at the neutral or stress free temperature, which is somewhere between the extreme high and low temperature of the rail depending on the geographical location. In the Netherlands the neutral temperature of the rails is set to 25°C.

During the installation or renewal of a turnout all the connecting rails should be brought to the neutral temperature or stress free temperature (SFT) in order to prevent malfunction of the turnout when the rail temperature increases. The SFT in turnout can be achieved by heating or pulling (pre-stressing) the rails [1]. It is important to control the neutral temperature of the rails in directly after the turnout installation as well as during its usage. In order to do so knowledge concerning the mechanical behaviour of a turnout is necessary.

In this study a turnout is modelled using the commercial software Ansys. The three-dimensional model of the turnout developed using solid elements with non-linear behaviour is tuned using the numerical and experimental results from [2]. Using this model a number of analyses with different temperatures and loading sequences corresponding to the turnout renewal procedure has been performed. The results have revealed some interesting phenomena in turnout behaviour. Also some critical places on the rails for possible locations of the sensors to measure the neutral temperature have been determined. In addition, the effectiveness of the non-linear model is compared to the linear one in the paper.

1

T. Arts, "Measuring the neutral temperature of a railway turnout during installation and use", M.Sc. Thesis, Section of Road and Railway Engineering, TU Delft, 2011.

2

S. Boogaerdt, "Achieving neutral stresses in a renewed switch and crossing", M.Sc. Thesis, Section of Road and Railway Engineering, TU Delft, 2009.

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