additional trunk meaning in Chinese

备用中继线/附加干线

Water supplies - combined fresh salt water supply projects - additional trunk transfer facilities to kowloon eastern areas and water supply to anderson road quarries site development - stage 1
供水食水供应-丹桂村食水配水库第ii阶段及元朗至屯门之间增设输水干管设施
Water supplies - fresh water supplies - integration of the north point and central cross harbour mains supply zones - remaining works water supplies - fresh water supplies - tan kwai tsuen fresh water service reservoir stage ii and additional trunk transfer facilities between yuen long and tuen mun
供水食水及海水供应工程项目-九东部增设干管输水设施及与安达臣道石矿场地盘发展有关的供水计划-第1阶段