A method of monitoring the operation of at least one work machine comprising: operating at least one surveying device to measure a surface profile of a terrain of a worksite and generate actual surface profile data indicative of the surface profile; operating at least one work machine to move along a route over the terrain in accordance with at least one actual operating parameter and generating actual machine operational data indicative of the at least one actual operating parameter, wherein the at least one work machine comprises at least one machine structure; operating a navigation system to determine the route and generate actual route data indicative of the route ; and operating a processing unit to process the actual route data, actual machine operational data and actual surface profile data to generate simulated monitored operating condition data indicative of at least one monitored operating condition of the at least one work machine moving along the route in accordance with the at least one actual operating parameter, characterised in that the simulated monitored operating data is indicative of at least one monitored operating condition of the at least one machine structure and the at least one monitored operating condition is different to the at least one operating parameter; the at least one monitored operating condition comprises a monitored stress and/or strain magnitude and/or rate experienced by at least one machine structure as the at least one work machine moves along the route ; and at least one terrain event is identified and at least one work machine is operated based upon the identified terrain event and/or an alert is generated, the at least one terrain event being identified at a location of the terrain where the monitored stress and/or strain magnitude and/or rate on at least one machine structure exceeds an event threshold value. operating at least one surveying device to measure a surface profile of a terrain of a worksite and generate actual surface profile data indicative of the surface profile; operating at least one work machine to move along a route over the terrain in accordance with at least one actual operating parameter and generating actual machine operational data indicative of the at least one actual operating parameter, wherein the at least one work machine comprises at least one machine structure; operating a navigation system to determine the route and generate actual route data indicative of the route ; and operating a processing unit to process the actual route data, actual machine operational data and actual surface profile data to generate simulated monitored operating condition data indicative of at least one monitored operating condition of the at least one work machine moving along the route in accordance with the at least one actual operating parameter, characterised in that the simulated monitored operating data is indicative of at least one monitored operating condition of the at least one machine structure and the at least one monitored operating condition is different to the at least one operating parameter; the at least one monitored operating condition comprises a monitored stress and/or strain magnitude and/or rate experienced by at least one machine structure as the at least one work machine moves along the route ; and at least one terrain event is identified and at least one work machine is operated based upon the identified terrain event and/or an alert is generated, the at least one terrain event being identified at a location of the terrain where the monitored stress and/or strain magnitude and/or rate on at least one machine structure exceeds an event threshold value. <EOS>