RULE 124. SERVICE LETTER. An engineer whose employment is terminated after having been in engine or hostling service thirty (30) days or more will, upon written request, be promptly furnished a service letter which he must sign before it is delivered to him. State laws will govern as to the form and information to be shown in service letters but where consistent with such laws, the service letter will show the period of employment, character of the service performed, and the cause of the termination of the service.