After having achieved significant improvements in our most important KPIs, including customer satisfaction and punctuality, we will continue to focus on operational performance on the track. It is important, therefore, to maintain the high quality of our performance and improve it where possible. Furthermore, we will continue to invest in improvements for passengers, such as new trains, upgrades to trains, renovations and improvements in and around stations, and further improving and speeding up the door-to-door journey for our passengers, for example through OV-fiets and by giving passengers an overview of the entire journey. We have set up a major investment programme to achieve this and at the same time cope with the forecast growth in mobility and passenger numbers.
The fixed costs will rise further in the next few years, due to the influx of new trains and the other investments that are needed to accommodate the predicted growth in passenger numbers. The increase in costs will partly be offset by a forecast rise in sales. In addition, various measures will be implemented to improve results. There will need to be further improvements to our result over the next few years if NS is to remain able to finance all the anticipated investments independently. In addition to sustaining high levels of operational performance, we will intensify our focus on further process improvements and the smart use of data to support this, to leverage further improvements in the result alongside effective management of the overhead and indirect costs. We should also note that Brexit and the discussions with the UK Department for Transport about the CLE settlement mechanism for our Greater Anglia franchise are factors introducing uncertainty in our expected results for the United Kingdom. The same applies to the amendments to agreements with German clients on compensation for higher personnel expenses due to the shorter working week and costs of training in connection with labour market shortages, and the amendment to the penalty regime in connection with the increase in works on the tracks, such that only punctuality within our control is included in the calculation. Healthy financial management requires our full attention.