G generally refers to high-speed EMU trains with a speed of more than 300KM per hour.
D generally refers to EMU trains with a speed of 200-300 kilometers per hour.
The "high-speed bullet train" beginning with G is more powerful, but it is also more expensive. It can only run on the newly-built "high-speed railway", so we commonly call it "high-speed train", which is one of the reasons why many cities want to build new high-speed railway station.
High-speed trains g and d can choose their own seats:
It is understood that on the basis of the pilot service of Hainan high-speed rail around the island in June 201June, the railway department began to launch the "independent seat selection" service for EMU trains in June this year.
When purchasing tickets through 12306 website or mobile app, passengers can choose seats according to the train seat map provided by the system. When the remaining seats can't meet the needs of passengers, the system will automatically allocate seats.