The paper describes two fast iterative algorithms for estimating the capacity of automated production lines with finite buffers. These algorithms are based on the linear programming formulation of the problem developed earlier by the author, and provide a range of values in which the throughput of the line is expected to lie. The throughput estimates of the two algorithms, compared with an estimate based on a simple workload analysis, indicate the amount of blocking/starvation as well as the probable causes of this unproductive time. The paper illustrates how inferences can be drawn from the two algorithms and used to improve the loading sequence and lot sizes. Managers can decide if the potential for improvement, which would be to get rid of all blocking/starvation, justifies the time to be spent on such an effort. New alternatives can be developed based on the insights provided by the algorithms and tested quickly.