Abstract: Critical Chain Project Management (CCPM) as a new concept originated at mid nineties and principally it had to take a long-term change in management perspective to adopt the unacceptable of past. In traditional project management language, the structure of a critical chain is similar to that of a "resource constrained critical path." Thus CCPM has been based and developed on the principles of Theory of Constraints (TOC). One of the main challenges of the CCPM is the adequate sizing of the time buffers. If the buffers were dimensioned beyond the necessary size, immediate practical implications happen. On the other hand, if buffers were underestimated it may increase the probability of duration overruns, which can represent financial penalties and reliable loss from the part of the customer or market. This paper is an attempt to apply the concepts and to explore the advantages of application of CCPM to a complex mega infrastructure project like construction of an elevated corridor for metro rail operations and also to compute the buffer size by some of the available methods. According to the sample analysis, it has been observed that the ‘Sum of Squares Method’ gives the maximum size of the buffer and the ‘50% method’ gives the minimum buffer size. Also application of CCPM may result in a reduction of the over all duration of the project by about 3%.

Keywords: Critical chain project management; Theory of constraints; Metro rail construction; Buffer sizing.