A measurement process, intended for measuring at least one wheel of a train, including an acquisition step, during which a plurality of profiles of at least a part of the wheel are acquired by plurality of optical sensors, as the train moves in front of the optical sensors, a mapping step, during which, for each optical sensor, the profiles acquired by the optical sensor are joined by a control module, to obtain a map of the part of the wheel further transformed into a cloud of points, a rejoining step, during which the clouds of points obtained from the optical sensors are joined to form a three-dimensional image of the wheel, and an analysis step, during which a plurality of reference points and reference distances are measured on the three-dimensional image.