Halachah distinguishes in this regard between a bus or train terminal, such as Yerushalayim’s Central Bus Station or New York’s Penn Station, and a bus stop on a street. When a person stands at a terminal, it is evident that he is waiting to board a bus or a train, and this is therefore inappropriate on Shabat. With regard to ordinary bus stops on the street, however, people very often sit there even if they are not planning to board or bus, or meet their friends there.
As such, standing at a bus stop does not necessarily reflect one’s plans to board a bus after Shabat, and therefore one may go to a bus stop to wait for a bus on Shabat, even if one goes there for the sole purpose of boarding a bus after Shabat. As mentioned, however, one may not walk to a bus or train station on Shabat to wait for his bus or train.