RULE 74. CALLING--YARD SERVICE.  (a) Regularly assigned yard service engineers and extra yard service engineers protecting vacancies of regularly assigned yard service engineers in outside yards will report for duty at their assigned starting time and starting point without being called.  

(b) At terminals where yard engineers' extra boards are maintained engineers required for irregular assignments in yard service and who reside within one and one-half miles from crew dispatcher's office will be called, as near as practicable, one hour before time required to report for duty. Where yard service engineers provide themselves with telephone service at their own expense they shall be called by telephone and the distance within which they shall be called shall not be limited.