SINGAPORE – The Land Transport Authority (LTA) and SMRT say they have been undertaking investigations into the cause of the intermittent loss of signalling communications between the trains and tracks on the Circle Line (CCL) from Aug 29 to Sept 2.
The signal disruption led to the automatic activation of the trains’ emergency brakes, which meant train rides were longer and jerkier.
Following a series of tests, LTA, SMRT and train manufacturer Alstom assessed that an interfering signal could have disrupted the trains’ signalling systems and led to the loss of communications.
According to a joint statement from LTA and SMRT, the source of the interfering signals was not uncovered as “the incidents had ceased by the afternoon of Sept 2”.
“Notwithstanding this, LTA and SMRT will install spectrum analysers within the Circle Line tunnels to detect the presence of any interfering signal. This measure will be extended to the North East Line, which has the same signalling system,” said the statement.
In the meantime, authorities will explore using electromagnetic shields on trains to minimise the impact of interfering signals, and also consider changing the signal system frequency.
It will also look at modifying the system “to provide redundancy in the event of signal interference”.
candicec@sph.com.sg
