A $15-billion light railway proposed by tycoon Mr Li Ka-shing to link Ma On Shan and Cheung Sha Wan should be carefully considered by the Government to help avoid serious future traffic problems in Sha Tin, district board members said yesterday. Plans for the 16.5-kilometre Cheung Ma Railway show the route is divided into four distance zones with charges between $3.20 and $6.90. Mr Li's flagship company, Cheung Kong (Holdings), plans to operate the line for 30 years before handing it over to the Government. Ma On Shan District Board member Mr Tsui Tung-hon said: ''With population increasing rapidly recently and in the coming two years, residents are worried that the road system with Lion Rock Tunnel and Tate's Cairn Tunnel will not be able to handle the flow and there will be serious traffic congestion. ''We hope the Government will seriously consider the proposal, since a large number of residents living here have to go to Kowloon to work.'' He said the fare was acceptable when compared with the $4 charged for buses running from Ma On Shan to Cheung Sha Wan. Travelling time for a full trip is estimated to be within 30 minutes. The buses take more than an hour. Sha Tin Tau District Board member Mr Lau Kong-wah said the transport system in Sha Tin had reached saturation point. ''If a private company is willing to pay for the cost of construction, the Government should seriously consider building the railway as soon as possible,'' he said. Cheung Sha Wan District Board member Mr James To Kun-sun, who is also a legislator, said: ''Although Cheung Sha Wan is already a very convenient place in terms of transport, it will be beneficial to the development of the West Kowloon Reclamation area ifthere is a mass transport system passing through there.'' However, all members urged serious consideration to be put on minimising the environmental impact. Cheung Kong's consultant, JMK Consulting Engineers, estimated daily usage during the opening year in 1997 would be 130,000. JMK's managing director, Mr Joseph Chow Ming-kuen, said it would increase to 220,000 people in 2011. Mr Chow said Cheung Kong would also have to develop property projects along the line. Property development is planned for five of the 13 stations - Ma On Shan terminus, Sha Tin Tau, Tai Wai interchange with the Kowloon-Canton Railway, Tin Sam and Cheung Sha Wan. The biggest property development will be a railway depot between Tai Wai and Tin Sam. Mr Chow said the Government would not have to subsidise Cheung Kong in building the railway, since the company would pay full commercial premium for the land. South of Tai Wai, the proposed railway will pass under the Shing Mun Country Park in a 2.5-km tunnel to emerge in West Kowloon near Lei Cheng Uk, before running again on elevated viaduct along Tonkin Street. The project will take 31/2 years to complete.