As the degree of sophistication of military equipment has increased, there has been a corresponding increase in the complexity of trainers, not only for the equipment, but also for the inter and intra service environments in which such military equipment will be used. The most explosive area has been computer software. Trainers and training systems have become a software-intense product. However, for a number of reasons, the perception of training systems users and training systems manufacturers alike is that each new training requirement is unique to such an extent that the required software must be newly developed each time. What are the causes of that perception, and is that perception accurate? Could software modules which perform specific functions be transportable among several training system families? Will the training system manufacturer who first proposes reusable software be in a position of favor for successive training system contracts? This paper not only addresses these questions, but also speculates on some in-roads which are being made in transportable training system software and examines the opportunities which this approach presents. One of the most significant of these is making training systems themselves able to be configured in multiple ways.