

Help: Visa questions to get back to Peru from Hong Kong via Shanghai
Hello,
My sister and I are two peruvians who flew to Shanghai to take a Royal Caribbean cruise. We had a 1-entry visa, which we used to get into Shanghai and out to the cruise. When we got back to Shanghai, they stamped us a 24-hour transit permit which allowed us to move to Hong Kong by train (via Shenzhen).
Right now, we are in Hong Kong trying to get back to Shanghai for our flight back on the 24th of February. We were wondering if they can stamp us another 24-hour permit when we take a train back to Shanghai, and when does the 'countdown' start (for example, if the 24-hour start to count from the moment we board the train or the moment we arrive at Shanghai). This is important because the trains from Hong Kong to Shanghai are usually 10 or more hours, sometimes with connections, and sometimes run only in even days. Our flight back (connection in Japan) is at 11am of the 24th.
We would appreciate any help regarding this subject and what procedures we can take.
Thank you!