SMRT今晚11时22分发推文证实，蔡厝港与兀兰之间的列车服务因为油池站发生信号故障造成的延误，已恢复运作，但运行时间仍需延长20分钟。到了晚上11时45分，SMRT再次发出推文确认，列车服务已恢复正常运行，原本提供的免费巴士接驳服务也已终止。
[NSL]UPDATE:Train services resumed. Pls expect add 20mins train travel time btwn#ChoaChuKangand#Woodlands. Free regular bus services are still available between#ChoaChuKangand#Woodlands.
— SMRT Corporation (@SMRT_Singapore) December 25, 2017
[NSL] CLEARED: Free regular bus svcs between#ChoaChuKang&#Woodlandshas ceased. Train service on North South Line had progressively returning to normal.
— SMRT Corporation (@SMRT_Singapore) December 25, 2017