As the trend towards more after sales services progresses through the industrial equipment industry, OEMs are now offering comprehensive service contracts in which they take full responsibility for the functioning of their customers’ machines. The growing responsibilities allow for more leeway in determining how to maintain the machinery. At the same time the OEM is directly effected by the success of its maintenance operations. This is certainly the case for capacity decisions in its field operations, which is the focus of this paper. One of the most important capacity decisions in field service operations is determining the training level of technicians. A field service organization can employ fully cross trained technicians which are trained to execute any service job. However, training and retaining these employees can be very expensive. Therefore, it can be cost effective to use dedicated technicians who received a focused training enabling them to perform a limited range of service jobs. We conducted a simulation study of the field service operations of an OEM in the compressed air industry to be able to evaluate the possibility to deploy technicians dedicated to preventive maintenance instead of fully cross trained technicians. We analyze the cross training decision for different scenariosin which a considerable part of the installed based is covered by service contracts. Due to these service contracts, maintenance demand as experienced by the field service organization is influenced by the cross training decisions. Ourcontribution consists of identifying the optimal cross training policy and the factors that influence the benefits of the different workforce configurations while taking into account the effect of the capacity decisions on the maintenance demand. We succeed to do this by characterizing the failure behavior of the individual machines. We find evidence that full cross training might be especially beneficial in a field service setting even when the effect on demand is taking into account.