Which line should I take from Shenzhen North to Gangxia North subway station?
Line 4, line 8. According to the inquiry of Shenzhen Metro, you can take Metro Line 4 from Shenzhen North Station, and then transfer to Line 8 at Citizen Center Station (Yantian Road direction). After one stop, you can reach Gangxia North Subway Station, so you should take Metro Line 4 and transfer to Line 8 when you arrive at Gangxia North Subway Station from Shenzhen North.