An accident of pantograph and overhead catenary system occurs not so frequently. But, once such accident occurs, long down-time of train service is unavoidable. For preventing accident between overhead catenary system and pantograph, overhead catenary system requires a lot of maintenance cost. To reduce this maintenance cost, the authors have developed a method which estimates the static height of contact wire by the contact force and the pantograph height. This paper describes the new method in detail and shows some simulation and experimental results.