It shall and may be lawful for all freight railroads, operating within the limits of the city of Philadelphia, to place salt upon their turn-outs and switches within the limits of said city, any law, or ordinance to the contrary notwithstanding; and further, that any fine or penalty hitherto imposed shall be and the same is hereby remitted and discharged, and any suit or claim brought for the recovery of the same is hereby directed to be discontinued and discharged; this act, however, shall not be construed to authorize the general salting of the track of any such railroads as aforesaid.
53 P.S. § 16807