A method for estimating damage to a railway vehicle, the method including steps of: recording route data on the routes over which the railway vehicle travels; measuring the operational condition external to the vehicle along the routes at the time of travel by the railway vehicle, the external condition being measured as one or more quantitative values; and estimating, for the or each quantitative value, a respective possible damage value using a cumulative exposure value which quantifies the cumulative exposure of the vehicle to the quantitative value over the recorded routes; wherein: in the measuring step, the amount of ice on overhead wires is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible pantograph shoe wear; and/or in the measuring step, the degree of rail roughness is measured as a quantitative value, and in the estimating step, respective possible damage values quantify possible wheel surface wear and/or possible distortion of wheel shape; and/or in the measuring step, the degree of rail distortion is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible distortion of wheel shape; and/or in the measuring step, the amount of snow on track is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible under-frame damage caused by ballast hit; and/or in the measuring step, the amount of air-born dust and sand is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible air conditioner damage. recording route data on the routes over which the railway vehicle travels; measuring the operational condition external to the vehicle along the routes at the time of travel by the railway vehicle, the external condition being measured as one or more quantitative values; and estimating, for the or each quantitative value, a respective possible damage value using a cumulative exposure value which quantifies the cumulative exposure of the vehicle to the quantitative value over the recorded routes; wherein: in the measuring step, the amount of ice on overhead wires is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible pantograph shoe wear; and/or in the measuring step, the degree of rail roughness is measured as a quantitative value, and in the estimating step, respective possible damage values quantify possible wheel surface wear and/or possible distortion of wheel shape; and/or in the measuring step, the degree of rail distortion is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible distortion of wheel shape; and/or in the measuring step, the amount of snow on track is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible under-frame damage caused by ballast hit; and/or in the measuring step, the amount of air-born dust and sand is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible air conditioner damage. in the measuring step, the amount of ice on overhead wires is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible pantograph shoe wear; and/or in the measuring step, the degree of rail roughness is measured as a quantitative value, and in the estimating step, respective possible damage values quantify possible wheel surface wear and/or possible distortion of wheel shape; and/or in the measuring step, the degree of rail distortion is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible distortion of wheel shape; and/or in the measuring step, the amount of snow on track is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible under-frame damage caused by ballast hit; and/or in the measuring step, the amount of air-born dust and sand is measured as a quantitative value, and in the estimating step, a respective possible damage value quantifies possible air conditioner damage.