§  98.  Intersection  of  railroads.  All  steam  railroads  hereafter  constructed across the tracks of  any  other  railroad  and  any  street  surface  railroad hereafter constructed across a steam railroad shall be  above, below, or at grade of such existing railroad as the  commissioner  of transportation shall determine, and the commissioner of  transportation shall in such determination fix the proportion of expense  of such crossing to be paid by each railroad.