The inter-city bullet trains from Tianjin Railway Station to Beijing is started with letter 'C'. The bullet trains depart every few minutes from Tianjin. Generally, no need to buy a ticket in advance, just but when you get there. The tickets may be short during the weekends. From the aiport to the railway station, You can take airport bus to Nanjing Road first and then take a taxi (10 yuan)or bus 50 (1.5 yuan) to Tianjin Railway Station.