In the Hong Kong subway (MTR), when two lines intersect, they intersect in two consecutive stations. Each station is for one connection direction. So you always can walk from Line 1 Platform A1 to Line 2 Platform A2 at Station A to go in one direction, and walk form Line 1 Platform B1 to Line 2 Platform B2 at Station B to go in the other direction when connecting. Confused? Make sense? THis is a very clever idea and it has been done a long time ago. For example, looking at the map above, going on green line south connecting south on red line, change at Yau Ma Tei. To go from Red line north connecting north on red line, change at Mongkok instead. Got i?