A railroad may raise or lower any public highway, not within the limits a municipality, for a railroad crossing, by petitioning the board of county commissioners, if the place is not a part of the state highway system, or by petition to the Department of Transportation if it is a part of the state system, but must guarantee to place and keep it in as good repair and condition as before the alteration was made, at its own expense. The grade approaching the crossing shall not exceed ten percent at any point thereof.
SDCL 49-16A-84