He stressed however that the government needed to think about sustainability in the long run. “The proposal of Bt15 per trip from the Transport Minister seems ambitious given that government has low tax revenue. The cost of subsidies would be high if infrastructure and train operations are taken into account,” he said. 
Sumet added that the rapid train fare in Bangkok is quite high in comparison to the income of local people&nbsp; 
By comparison using purchasing power parity method , Thais pay Bt28.30 per one-way trip on average, or 50- per-cent more than their counterparts in Singapore where the average fare is Bt13.3 per trip, according to a study conducted by TDRI and led by Sumet. 
An average ride in Hong Kong is Bt16.78per trip. 
He said low-income and middle income groups have the ability to pay Bt11.69 and Bt20.33 per trip, much lower than actual fee charges today. 
He also anticipated that fares would rise to Bt100 per one-way trip once more more mass transit lines in Bangkok open for service.

Mass transit fares must be kept down: academic

Sumet Ongkittikul, research director at the Thailand Development Research Institute(TDRI) , said that he generally supported the plan to reduce and limit fares to allow everyone to access the rapid mass transit services .