Clementi rail accident

The 1993 Clementi rail accident was a rail accident that occurred on the East West line of the Singapore MRT. It was the MRT's first major incident and resulted in 156 passengers being injured. It was caused by a oil spill.
Background.
The MRT commenced operations in 1987, with the part of the line from Outram Park MRT station to Jurong East MRT station opening on 12 March 1988. At the time of the accident, the system had been operating for six years.
Incident.
Before the start of service, a maintenance vehicle leaked oil onto the tracks from Buona Vista MRT station to Clementi MRT station until the junction with Ulu Pandan Depot. The first 10 westbound trains reported braking difficulties. The eleventh train, a C151, had to use its emergency brakes to stop at the station. At 7.50 am on 5 August 1993, the 12th train, another C151, collided with the stationary C151 at Clementi while it was recharging its batteries, resulting in 156 injuries.
Investigation.
the investigation showed that the cause of the accident was a oil spill caused by a defective rubber ring on a maintenance locomotive.
Aftermath.
Response.
In the aftermath of the accident, SMRT said that it would replace the faulty maintenance locomotives and purchase new ones. It also introduced a new policy for station managers to inspect tracks for oil or foreign objects before the start of service.
Joo Koon rail accident.
The second collision on the MRT, the Joo Koon rail accident, occurred 24 years later on 15 November 2017, when two C151A trains collided at Joo Koon MRT station.