RULE 72. ARBITRARIES.   Where it has been the practice or rule to pay a yard engine crew or either 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 the 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 yard-road service rule.