Service replanning in urban rail transit networks: Cross-line express trains for reducing the number of passenger transfers and travel time

•Transfer routes choice and in-vehicle time saver under the variable stopping patterns and turn-back stations for cross-line trains.•Frequency-setting requirements on both lines caused by headway constraints between cross-line trains and local trains running on the same track.•The established model (ISPOM) can be applied to most real-world URT networks, to quantify the effectiveness of the cross-line express operation mode in practice, due to no requirements on overtaking facilities equipped.