While rail operators face much stiffer fines for disruptions now, the Land Transport Authority (LTA) said it will consider imposing the maximum penalty only for "the most serious of incidents".
Its spokesman said these could involve safety breaches or multiple violations of service standards and regulations. For instance, the LTA has imposed the previous maximum fine of $1 million twice - for the massive North-South Line disruptions on Dec 15 and Dec 17 of 2011, which crippled the network for five and seven hours respectively and affected 221,000 commuters in total.
On Monday, Parliament raised the penalty cap for each incident to 10 per cent of the annual fare revenue of the affected line or $1 million, whichever is higher.
Based on SMRT's fare revenue for its 2013 financial year, the maximum penalty for a disruption on the North-South or East-West line could be about $49 million.
The spokesman said the LTA will look into the facts of each rail incident, how severe the breaches were, and if other licensing conditions were violated when deciding the size of a fine.
It will also consider aggravating or mitigating factors such as whether the operator had full control of the incident, how it managed the breakdown and its service recovery, she added.
Dr Park Byung Joon, head of the urban transport management programme at SIM University, said the previous cap would not have any critical impact on the financials of SMRT or SBS Transit.
The new cap, however, sends a clear message that the Government will not just issue an "institutional reminder" if the operators fail to perform. "The maximum fine now can put the operators in an instant financial crisis - 10 per cent of annual fare revenue is a huge amount," he said.
The fines however should not be so high as to put the operators out of business, he added. Hence the decision on how much to fine must be carefully made on a case-by-case basis.
In response to the heavier penalties, SMRT and SBS Transit said they remain committed to improving the reliability of their train services.
The legislation passed on Monday also gave the LTA power to beef up the boards of both public transport operators, if needed.
The LTA spokesman said that there are "no current plans to invoke this provision".
Meanwhile, the authority has awarded $1.09 billion in contracts to a trio of firms from Japan and Hong Kong to build the Sin Ming, Havelock and Marina Bay stations on the Thomson Line.
Construction work is expected to start by the first quarter of this year. Sin Ming station will be completed in 2020, and Havelock and Marina Bay stations will be ready a year later, in 2021.
The biggest contract, to build Sin Ming station and its tunnels for $454 million, went to Japan's Penta-Ocean Construction. Another Japanese contractor, Taisei Corporation, won the $425 million deal to build Marina Bay station, while Hong Kong firm Gammon Construction Limited Singapore Branch clinched the $210 million contract for Havelock.
All three companies have won previous tenders. Penta-Ocean, for instance, was responsible for the already completed Expo and Kranji stations, while Gammon is currently building the Thomson Line's Mayflower station.
To date, the LTA has awarded 13 civil contracts worth $4.26 billion for the $18 billion, 22-station Thomson Line.
To be completed in three phases from 2019 to 2021, the 30km line runs from Woodlands in the north to Gardens by the Bay in the south, where it will connect to the future Eastern Region Line.
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