Transit Visa Required????

I am a UK citizen and I am flying (United Airlines) from San Francisco to Beijing, then connecting immediately (with a few hours lay-over) to a domestic Air China flight to Chengdu, followed immediately (after a few hours lay-over) by an international Air China flight to Katmandu (Nepal). I am a UK citizen with a green card (resident alien) status in the USA. Do I need a transit or tourist visa for this trip? I am NOT leaving any airport within China, but will probably have to pick up my luggage in Beijing and transfer it to the domestic flight to Chengdu which connects to the flight to Nepal. Do I require a tourist or transit visa, or none at all??