Hi

I will be in Tokyo in August and want to make use of the 144 hour free transit visa on the way back to Switzerland

My question, can I land in Shanghai, spend 2 days there, take a train to Beijing and after spending 2 days there leave from Beijing again

Both airports are allowed for the visa, just dont know if I am allowed to visit both regions on same stay and if the train travels through regions that might not be covered
Thanks for your input