The damning revelation that SMRT staff may have doctored maintenance records on three occasions is alarming, as it further shakes public confidence in the transport operator and raises serious questions about its maintenance regime.
Initial investigations into the Oct 7 disruption found that two float switches which controlled the pump system did not kick in, resulting in water flooding the tunnel between Bishan station and the underground Braddell station.
The flood-prevention devices that failed were last inspected in June, according to SMRT.
But as it turns out, the staff responsible for maintenance may have submitted false records for three consecutive quarters, including the June period, to say they had carried out works on the pumps and switches when they did not.
Were these incidents isolated cases, where a handful of staff did not do the work they were supposed to and lied to cut corners?
Or do they point to a more systemic issue within the company, where there are more such cases yet to be uncovered?
SMRT made maintenance one of its top priorities after two major disruptions in December 2011, which triggered a public inquiry. It tightened maintenance procedures, and said it has beefed up its team of engineers by more than 150 per cent in the last four years.
So why is SMRT's maintenance culture still found wanting in some areas?
The operator has pledged to address the rot via several measures, including bringing in external experts to inspect critical systems across its entire rail network. This move will help address concerns about similar maintenance lapses across the MRT system.
SMRT also said it will hold all relevant management along the chain of command accountable, and intensify training to instil greater work responsibility. The transport operator has already removed and redeployed its senior executive, Mr Ng Tek Poo, who was in charge of maintenance and systems.
The new joint readiness inspection team that SMRT is setting up with the Land Transport Authority (LTA) will also provide an additional layer of checks to ensure maintenance is done properly.
To be fair, there are many dedicated staff within SMRT who consistently give their all to keep the rail network, which sees more than three million trips a day, running smoothly.
Yet as the flooding incident has shown, it takes only a handful of individuals to unravel the hard work put in by others, and dent confidence in the company.
That is why SMRT has to take steps to stamp out all instances of staff not doing their job to avoid future disruptions caused by such maintenance lapses.
Meanwhile, LTA is carrying out its own investigation into the incident, and will make its recommendation on penalties for SMRT to the LTA board in due time.
During a press conference last month, Transport Minister Khaw Boon Wan had said he would prefer not to "go back to this old system of penalties and fines" as it created "a very adversarial relationship" between the regulator LTA and rail operators. But fines should still be imposed for severe disruptions when warranted, so that operators are hit where it hurts the most - in the wallet.
The LTA will also work with SMRT to improve the redundancy of flood prevention measures, including additional radar sensors to activate pumps.
These are the latest measures to improve the reliability of the MRT network. Other multimillion-dollar initiatives include replacing the entire power-supplying third rail, upgrading the signalling system and overhauling the power supply system on the older North-South and East-West lines.
However, these major infrastructure renewal projects must be coupled with a proper maintenance regime. They will not work if maintenance staff are not doing what they are supposed to do.