岔线 meaning in English

branch line
sidetrack
siding
y-track

Railway private sidings refer to the branch railway lines which are administered by enterprises or other units and are connected to a state railway line or any other railway line
铁路专用线是指由企业或者其他单位管理的与国家铁路或者其他铁路线路接轨的岔线。
The calculation is based on the actual length of the first line even if this line has a full or partial double track or more tracks , excluding double tracks , stationsidings , tracks under the charge of stations , , branch lines , specialpurpose lines and the non payable connecting lines
凡是全线或部分建成双线及以上的线路，以第一线的实际长度计算；复线、站线、段管线、岔线和特殊用途线以及不计算运费的联络线都不计算营业里程。