The MTR Corp (MTRC) is expected to be locked in a fierce debate with legislators tomorrow over the thorny issue of funding for the proposed loop rail line on southern Hong Kong Island. With the approval of the government, the company recently revised the proposal, known as the South Island Line, by offering alternative routes and looking into funding and technical requirements, according to Legislative Council papers prepared for the Transport Panel meeting. The rail proposal will set the stage for a test of whether the MTRC and its majority shareholder - the government - will be able to finalise a large-scale rail project with a commercial return promised at the time of its partial privatisation in 2000. The railway company is seeking a return of 1 to 3 per cent above its average cost of capital on the South Island Line, but it will only be possible with support from the government. 'MTRC's preliminary financial assessment suggests that the South Island Line and West Island Line will not be a financially viable project based on fare revenue alone,' the Environment, Transport and Works Bureau said. An MTRC spokesman said yesterday it was premature to estimate the cost and funding shortfall of the South Island Line. The revised plan includes the first phase of the West Island Line, an extension from Sheung Wan to the Belcher's through Sai Ying Pun. Analysts said the cost of the revised project would be less than $15 billion.