In a Facebook Post by SMRT at around noon, the rail operator explained that urgent repairs undertaken to repair a track point the night before was unable to be completed in time for the start of train services. As such, the track point was locked in one direction, resulting in only one operational platform at Joo Koon.
Track points (or track switches) are the mechanical installations that guide trains from one track to another, and play an especially important role at terminal stations where they are actively used to guide trains in and out of both platforms.
During normal operations, both platforms at Joo Koon are used for train turnarounds. With Platform A out of service since the start of service due to the faulty point before Joo Koon, resulting in trains not being able to cross from the westbound track to the eastbound track.
Morning Peak Hour
Trains were only able to turnaround at Joo Koon Platform B (Westbound). As such, a backlog of trains queuing up to enter Joo Koon formed at about 0700hrs, as the westbound trains from Pasir Ris, additional westbound trains from Changi Depot and Ulu Pandan Depot (via Tanah Merah and Jurong East respectively) reach the western terminus at Peak Hour frequency (about 2 – 4 mins per train).
At about 0830hrs, the resulting train congestion reached its highest impact point, where SMRT tweeted a delay of 25 mins between Jurong East and Joo Koon. Eastbound trains ran at about 4 – 5 minutes frequency, resulting in many commuters unable to board packed trains at major stations such as Boon Lay, Jurong East and Buona Vista. Despite 25 minutes of additional traveling time for commuters, free bus boarding for affected stations was not activated.
— SMRT Corporation (@SMRT_Singapore) February 7, 2017
Evening Peak Hour
During the evening peak hours, westbound East West Line trains were made to terminate at either Boon Lay or Jurong East during the peak hours. Both stations have crossover points, allowing trains to be reversed back onto the Eastbound tracks heading back towards Pasir Ris.
During the evening peak hours, only one-third of trains ran to Joo Koon. One-third ended at Boon lay, while the last one-third ended at Jurong East. This arrangement resulted in higher levels of congestion between Jurong East and Joo Koon. Many passengers were also greeted with the unique sight of multiple terminating stations along the East West Line.
At Raffles Place and City Hall, the Rail Travel Information System (RATIS) reflected a unique situation where trains to Jurong East were departing from both North South Line and East West Line stations.