If one takes that train you mean to say you need not apply for a PRC Visa which is $50 for a 1 time entry/
Otherwise thats a very expensive stamp if thats all the OP wants. But still 1/2 the rate for a Brazilian which is $100 , same by Chile. But at least by the last 2 its good for the Life of Ones Passport so it can be used numerous times , unlike the Chinese which is a 1 shot deal.