THE Mass Transit Railway Corp (MTRC) announced yesterday it had signed a $500 million term-loan facility with the Union Bank of Switzerland, a move that it said reflected the confidence of international investors in the company. MTRC finance director Roger Moss described the five-year loan as important because it involved an AAA-rated Swiss bank and extended beyond the handover of Hongkong to China in 1997. ''Clearly it is an indication of the support the company enjoys with institutions of the highest worth in the world,'' he said. Mr Moss said it clearly signalled that the MTRC's strong debt rating and relationships put it in an excellent position to raise large amounts of capital in international markets to finance airport-related projects. The loan, the largest made by Union Bank to the MTRC, matures in 1998. It has a draw-down period of 33 months and carries a margin over the Hongkong Interbank Offered Rate. The MTRC said the proceeds would be used as general working capital. So far this year, the MTRC has borrowed $3 billion to refinance existing debt and for working capital. Mr Moss said the airport railway would cost $33 billion, assuming it was completed by 1997. Once the airport project received final approval, he said, the MTRC planned to borrow $10 billion a year to finance the railway. He said the company had continued to meet banks, security houses and investors around the world to keep them up to date on developments in Hongkong so that financing for the airport project could easily be arranged. In April, the MRTC issued two seven-year tranches of debt paper to institutional investors, which will mature in May 2000. It also refinanced a total of $300 million of fixed-rate borrowings to take advantage of lower interest rates by issuing new fixed-rate notes. A recent government report said private investment should play a major role in the construction of the airport railway network, which will cost $65 billion. It suggested that the railway's developers be given the right to develop property along the line to attract private investment because projects of this sort were mostly financially unattractive.