This paper investigates the stochastic behavior of a redundant system having problem of waiting line in the maintenance section in terms of various aspects such as reliability, availability, sensitivity etc. The system under consideration has three parts X, Y and Z connected in series. Each part has two units. Out of which part X has one main unit and other applied redundant unit. Similarly part Y has one main unit and other cold redundant unit to support the system. When main units of both the part have failed, then redundant units start automatically. While part Z has two units connected in parallel configuration. Here a realistic situation is discussed that when main units and redundant units of part X and Y are failed and arrived for repair then due to unavailability of repair men a line is generated there and its affect on systems reliability. So the focus of the study is to investigate the nature of the system using supplementary variable technique with the application of copula methodology under the condition when all four units are in line for repair.