1) Just because something is possible, doesn't make it the trend. It makes it an exception to the rule. What are the odds that it's going to work? Look back at the last 2 years of it not working, then some pennies might drop.
2) Subsidies are always more expensive than their cost, when viewed in the bigger picture.
 You would need something more convincing to suggest that a subsidy would fix the skewed incentives and vested interests you yourself have identified as causing the metro rail to flop.

Maybe look at the trend with other state-owned enterprises and see how the subsidies I mean bailouts are working for us as consumers there.