【明報專訊】OVER the last two or three months, there have been frequent breakdowns, both major and minor, on the MTR system. Most recently, faulty insulators along the East Rail led within ten days to two breakdowns, which lasted four and three hours respectively. As railways constitute the backbone of Hong Kong's transportation system and all other forms of transport are of an auxiliary nature, buses and minibuses can hardly be expected to meet adequately the sudden increase in transportation demand, however well they are mobilised, when rail services are disrupted.