Logistics service providers deal with the challenge of estimating future freight transport demands due to the increasing volatility. Short-term planning horizons and planning uncertainties cause reduced capacity utilization and increasing empty mileage. Due to higher flexibility of road transportation, planning uncertainties in freight transport lead to using the road as a preferential mode of transport in most cases. Thus, more ecologically sustainable, but less flexible modes of transport as rail or waterway are omitted. To overcome the aforementioned challenge, a multistep approach is proposed to continuously plan future transport capacity in order to redesign and adjust the intermodal fleet accordingly. The proposed multistep approach combines methods of forecasting, multi-period intermodal routing and decision support for capacity adjustments. Finally, we present first results on a use-case of outbound logistics in automotive industry and give an outlook on our future research.