Any wagon, buggy, motor vehicle, water or air craft or other vehicle or conveyance in which is stored, contained or transported any narcotics or drugs, the possession or transportation of which is in violation of any law of this Commonwealth, shall be forfeited to the Commonwealth subject to the provisions hereafter set forth:¹ Provided, however, That nothing herein contained shall be construed to apply to common carriers by railroad subject to Part 1 of the Interstate Commerce Act.²