The operator of Bangkok's BTS Skytrain has assured passengers it has found the right solution to fix signal interference glitches and promised a full recovery of its services, plagued this week by rush hour delays, from Saturday.
BTS Group Holdings Plc said it would bring up for discussion with City Hall demands for compensation for commuters left stranded on its stations during the delays.
The problem, which caused extensive delays from Monday to Wednesday, is being resolved by a new radio transmission system to be installed which will allow it to switch to a new frequency spectrum to better control train traffic.
"We're confident we're on the right track to solving the problem," BTS Group Holdings' executive director and chief adviser Anat Arbhabhirama said.
The firm believes communications between its trains in the 2,400-MHz spectrum were disturbed by a radio frequency in the 2,300-MHz spectrum, making it unable to have the trains run and stop in automatic mode.
This issue should be fixed as the BTS will use a new radio signal near the 2,500MHz frequency as suggested by the National Broadcasting and Telecommunications Commission, Mr Anat said.
It expects to finish installing the new transceivers tonight.
"We'll assess the outcome [of the new frequency] on Monday," Mr Anat said, adding the moment of truth will be known on Monday morning when many commuters will take the train and use their phones and streaming services at the same time.
State-run telecommunications company TOT and Total Access Communication (DTAC), which are licensed to use the 2,300-MHz spectrum, were suspected to have caused the signal interference.
Mr Anat said trains resumed normal operations Thursday morning after TOT temporarily shut down 10 of its 2,300-MHz base stations along the Skytrain routes.
However, TOT senior executive vice-president Rangsan Channaruekul insisted the 2,300-MHz spectrum was not the cause of frequency interference that led to the delays.
But he said mobile phones, which vary in their model specifications, could be using the frequency in various ways.
He suggested the operator monitor radio signals connected to other devices including security cameras to prevent any future glitches.
Bangkok Mass Transit System Plc (BTSC) chief executive Surapong Laoha-unya said stranded commuters were given a remedial solution. Nothing was deducted from their value-added cards for the trips affected by the delays. Those using single-trip cards can also collect them for reuse within 14 days.
Next week the BTSC will also meet City Hall, which granted the company the Skytrain service concession, to discuss compensation measures for commuters affected by the delays after the city reportedly planned to fine the company 1.8 million baht.
The delays forced many commuters to migrate over to the MRT (subway), Mr Surapong said.
The Skytrain serves about 730,000 commuters daily. The delays forced BTS staff to manually control the trains and reduce trip frequency.