We consider tandem queueing systems that can be formulated as a contin
uous-time Markov chain, and investigate how to maximize the throughput
when the queue capacities are limited. We consider various constraine
d optimization problems where the decision variables are of one or mor
e of the following types: (1) expected service times, (2) queue capaci
ties, and (3) the number of servers at the respective stations. After
surveying our previous studies of this kind, we open up consideration
of three new problems by presenting some numerical results that should
give some insight into the general form of the optimal design.