La. Stat. tit. 33 § 3355
In lieu of the above, and upon the written petition of the owners of sixty per cent of the lineal front footage of the property abutting on any street or alley, the entire costs, of the improvements, shall be paid by the owners of the real estate abutting upon the streets or alleys, to be improved, according to the frontage of the property owned by them provided that where a railroad bed or track occupies a portion of the street or alley to be improved, the owners thereof shall pay the entire costs of paving of the space occupied by the railroad bed, including extra work made necessary by the presence of the track, and provided further that in the event the railroad bed or track, including street railroad bed or track, is owned by the municipality, it shall pay only for the extra work made necessary by the presence of the track in the street.
La. R.S. § 33:3355