M.Comm. / Operational management is to plan and control the transformation process that converts the requirements of customers into a product or a service. The non programmed refurbishing of railway wagons at Transwerk (Germiston) is a very difficult task for the operational manager. The number of wagons and what to repair on each wagon, only become known when the wagon arrives at Transwerk. The planning and scheduling of resources like labour, material, facilities, equipment and cash flow are therefor not so easy. To overcome the difficulties of the planning and scheduling of resources, and to refurbish the wagons according to the customer's requirements and satisfaction, it is necessary to have an operational management model or system. This system comprises of functions like aggregate planning, production scheduling, planning for fixed and variable capacities, inventory planning, design of the operational process itself as well as the control of the whole system. All of this must be set in a framework of the company's overall strategy as well as the financial and operational strategies. The first part of this study deals with the heories of operational management. It is important that the operational manager is familiar with the types of decisions to be made and what concepts are available to optimise his decisions. He also needs to know which product positioning strategy and which process positioning strategy to take. In the case of Transwerk a make-to-order product positioning strategy will be used to refurbish the wagons, and a make-to-stock strategy to manufacture the components that are needed to repair the wagons. A job-shop process positioning strategy will be used, because no fixed process flow can be followed to repair the different wagons. In the second part of this study an empirical research was done. The frequency and number of the different types of wagons that were sent to Transwerk, as well as the occurrence of the repair types on the wagons, were researched. Four years (1992 to 1995 book year) of information were used. The number of wagons and when the wagons might come in for repairs in 1996, as well as what types of repairs to do, are forecasted by using quantitative techniques as time series decomposition and weighted moving averages. The forecast or aggregate plan is the starting point of any operational model. Finally the operational model is designed. The model starts with the business- and operational strategies followed by the production plan. The production plan, derived from the forecast, shows the wagons that are expected to be built for the next five years. Transwerk should check the major available resources to assure that the production can be met. After the production plan is authorised by the executive manager the operational manager can do the master schedule. This schedule shows by model level which wagon types are expected to be repaired per day per month. This information also comes from the forecast that was done. Out of the master schedule, the material- and capacity plans can be drawn up. Production can start once the operational manager finds the planning to be correct. It is important that every step in the model is controlled and that the plans are changed if necessary. A well defined operational management model will help Transwerk on the way to be a world class company.