Automatic transfer lines are playing an increasingly important role in production. As production rates and capital investment increase, the cost of line stoppages also increases. A line stoppage of an automatic transfer line occurs everytime any of the machines stops, unless there is a sufficient buffer stock between each machine in the line. Thus there arises the question of how much buffer stock between each machine is required to optimise line operation in accordance with some criterion such as maximum output or minimum cost. Though it is fairly easy to formulate this problem in mathematical terms, it has been shown (Ref.1) that an analytical solution is not possible. The problem can, however, be solved for each particular case by simulation. This report describes one such solution for the case of an automatic bottling plant in a brewery. The work was carried out as a thesis project for the college's diploma, by Mr. A.C. Roberts, a student in the Statistics and Operational Research section, School of Management, during the Academic year 1967/68. Mr. E. Kay of the Materials Handling Research Unit acted as project supervisor. As a bottling line is a prime example of an automatic transfer line, we believe that the method here described can be applied to all similar problems.