A method of checking if information about an operating state of a vehicle, in particular a rail vehicle, to be displayed on a display is correct, wherein the display is adapted to display pictures comprising pixels, wherein - the information is to be displayed in a predetermined region of the display, - the information to be displayed on the display is used or has been used to generate a picture data set which comprises the data necessary for producing a corresponding picture on the display, - the information comprises a first type of information and a second type of information which are to be displayed in the predetermined region, - the first type of information is to be displayed using pixels of a first predetermined colour and the second type of information is to be displayed using pixels of a second predetermined colour, - a first characteristic value of the information is calculated and a second characteristic value of the information is calculated, wherein the first and second colours differ and the method comprises the steps of: - modifying, before calculating the second characteristic value, the picture data set corresponding to the picture to be displayed in the predetermined region by changing the pixels of the first predetermined colour to a third predetermined colour, which differs from the first colour, thereby eliminating the first type of information with respect to the calculation of the second characteristic value, and optionally changing other colours, thereby obtaining a first modified data set, - modifying, before calculating the first characteristic value, the picture data set corresponding to the picture to be displayed in the predetermined region by changing the pixels of the second predetermined colour to a fourth predetermined colour, which differs from the second colour, thereby eliminating the second type of information with respect to the calculation of the first characteristic value, and optionally changing other colours, thereby obtaining a second modified data set, - calculating the first characteristic value from the second modified data set, - calculating the second characteristic value from the first modified data set, - selecting a first expected value, which corresponds to the first type of information to be displayed, and comparing the first characteristic value with the first expected value, - selecting a second expected value, which corresponds to the second type of information to be displayed, and comparing the second characteristic value with the second expected value, - if the comparison is non-successful, i.e. there is a significant difference between the respective expected value and the characteristic value, taking a corresponding pre-determined action. - the information is to be displayed in a predetermined region of the display, - the information to be displayed on the display is used or has been used to generate a picture data set which comprises the data necessary for producing a corresponding picture on the display, - the information comprises a first type of information and a second type of information which are to be displayed in the predetermined region, - the first type of information is to be displayed using pixels of a first predetermined colour and the second type of information is to be displayed using pixels of a second predetermined colour, - a first characteristic value of the information is calculated and a second characteristic value of the information is calculated, - modifying, before calculating the second characteristic value, the picture data set corresponding to the picture to be displayed in the predetermined region by changing the pixels of the first predetermined colour to a third predetermined colour, which differs from the first colour, thereby eliminating the first type of information with respect to the calculation of the second characteristic value, and optionally changing other colours, thereby obtaining a first modified data set, - modifying, before calculating the first characteristic value, the picture data set corresponding to the picture to be displayed in the predetermined region by changing the pixels of the second predetermined colour to a fourth predetermined colour, which differs from the second colour, thereby eliminating the second type of information with respect to the calculation of the first characteristic value, and optionally changing other colours, thereby obtaining a second modified data set, - calculating the first characteristic value from the second modified data set, - calculating the second characteristic value from the first modified data set, - selecting a first expected value, which corresponds to the first type of information to be displayed, and comparing the first characteristic value with the first expected value, - selecting a second expected value, which corresponds to the second type of information to be displayed, and comparing the second characteristic value with the second expected value, - if the comparison is non-successful, i.e. there is a significant difference between the respective expected value and the characteristic value, taking a corresponding pre-determined action.