Single Queue example model in TreeAgePro 2018.
TreeAge Pro 2018 R1.0 introduced new node types (Stop and Entry nodes), which make it easier to build queueing models using fixed cycle Markov structure. Another new feature which is important for queue modeling are Global Trackers, which can be used to store values specific to a particular strategy and shared by all trials (patients) evaluated within that strategy. The attached model implements simple First In First out queue with exponential arrival time and exponential service time. Two strategies can be assigned different numbers of resources (e.g. hospital beds, doctors, etc.) allowing for comparison of maximum queue lengths, resource utilization, etc. under different parameters.
In addition to a TreeAge Pro model, there is a document describing the model in more detail as well as overview of queuing theory.