RULE 9. IRREGULAR SERVICE,  (a) Yardmen required to perform other than their regular duties will receive not less than their regular rates. This will not apply to yardmen voluntarily accept­ing other service at prescribed rates for such service.

     (b) Where it has been the practice or rule to pay yard crew or any member thereof, arbitraries or special allowances, or to allow another minimum day for extra or additional service per­formed during the course of or continuous after end of the regularly assigned hours, such practice or rule is hereby elimi­nated except where such allowances are for individual service not properly within the scope of yard service, or as provided in section (c).

     (c) Where regularly assigned to perform service within switch­ing limits yardmen shall not be used in road service when road crews are available, except in case of emergency. When yard crews are used in road service under conditions just referred to, they shall be paid miles or hours, whichever is the greater, with a minimum of one hour, for the class of service performed, in addi­tion to the regular yard pay, and without any deduction therefrom for the time consumed in said service.