Pressure signals measured in gas pipelines provide useful information for monitoring the status of pipeline network operations. This study numerically investigates leakage detection and location in a simple gas pipeline branch using transient signals from an array of pressure sensors. A pipeline network simulation model was developed and used to predict one-dimensional compressible flow in gas pipelines. Two monitoring methods were tested for leakage detection and location; these include cross-correlation monitoring and pressure differential monitoring. The performance and reliability of the two monitoring methods were numerically assessed based on simulation results for a simple pipeline branch operation with a prescribed leakage rate (5% of total flow rate in the gas pipeline).