There are two small-bore low-speed diesel engines with ECOEGR system on the rail car carrier, to meet the requirements of TIER III emission control regulations. This main engine with ECOEGR, and it"s ECOEGR piping system are the first design in the world. Based on the vessel, the technical details of analyzing the working principle and real ship arrangement for small bore low-speed diesel engine with ECOEGR system. It provides valuable reference for the design and construction of the ECOEGR system for the future possible follow-up ship or similar small-bore low-speed diesel engine with ECOEGR ship.