All train drivers have received training for the routes that they drive and, with experience, develop individual driving styles. They will know the route, traction and service pattern intimately: these elements are critical to safe, optimal driving. Change means that drivers may need to acquire new knowledge and update their driving style; it can also cause feelings of discomfort. It therefore requires careful management. Changes are often introduced to improve operations, for example, to improve drivability or to reduce risk, and everyone affected should understand the reason and need for the change.