Confused by the MTR

Today I have been baffled by the MTR; in particular, why is the train going to Sheung Wan from Tin Hau below the train going in the opposite direction, when if you go five stops east to Sai Wan Ho, it's *above* the train going away from Sheung Wan. It doesn't make sense to me, unless the MTR engineers studied under MC Escher (stalwart of the south-west London breakbeat scene, and also the guy who drew those staircases going up to nowhere), and they thought it was a good idea for the tunnels to constantly be moving around one another.

I mean, it's possible that Hong Kong splashed a fortune on physics-defying, space-time continuum warping trains, rather than bothering with tunnels that stayed at the same relative depth to one another throughout the network, but it hardly seems likely. Apart from anything else, it would have cost a huge amount, and it's not as if money is ever spent here on hugely capital-intensive infrastructure projects with no realistic chance of return.

Erm.

Apart from the bridge to Macau, that is.

And the train to Guangzhou that doesn't really go to Guangzhou, just somewhere 45 minutes' drive away.

When there's already a train to Guangzhou.

And the exposition centre at the airport that nobody uses (apart from when Slash comes to town, and only then to embarrass him by providing a hall too big to ever be filled by an audience.)

And the rumoured scheme to make all the mountain bike trails wheelchair-compatible.¹

But... Well, all the above schemes make perfect sense, once you assume the existence of a man who owns a cement factory and is best friends forever with somebody in the Planning Department. But since there's nobody with a vested interest in multi-dimensional physics warping apparatus in Hong Kong ², the impractical topology of the underground train system continues to leave me baffled.

¹ No, I'm not saying people in wheelchairs shouldn't be able to go out into the countryside. But I don't see why you need to build a wheelchair ramp for *everything*; there's nobody pressing for a pedestrian crossing at the Happy Valley racetrack.
² I haven't been to the research department at Hong Kong University. All bets might be off.