You’re driving on a two-lane road and stopped behind a city bus. Is it legal to pass? If that had been a school bus, it clearly would have been illegal, and the lights and signs on the bus would have made that abundantly clear. However, the rules are different for city buses.
Any person driving a school bus and approaching a railroad-highway grade crossing shall stop within 50 feet but not less than 15 feet from the nearest rail of such railroad and shall not proceed until he or she can do so safely when a highway sign is indicating that a train is approaching or when the driver can hear or see an approaching train.