It is unlawful for any person to climb upon, hold to, or in any manner attach himself to, any railway train, locomotive, or railway car while such is in motion within the city, unless such person is acting in line of duty; or to board any train or railroad car, including a passenger, freight, or other car, except with a proper ticket or the permission of the person in charge of the train or car or in line of duty. (1990 Code § 16-103)