This document provides a review of the box pushing technique used for rail under bridge construction. It discusses how box pushing involves precasting concrete boxes and then pushing them into place under live rail lines using hydraulic jacks, allowing construction with minimal disruption to train traffic. The summary explains the key steps of box pushing including excavation, laying the thrust bed, casting and pushing the concrete boxes, and constructing the road foundation. Advantages are minimizing traffic disruptions while disadvantages include needing skilled workers and only allowing daytime work.