N.J. Stat. Ann. § 54:1-18

If it shall appear, by written complaint of a taxing district or county, that another taxing district or county which is by taxes contributing to a common cause with the complainant, is by inequality of valuation or otherwise avoiding or escaping its fair share of the common burden, the commissioner shall cause an investigation of the complaint to be made, and shall render all possible assistance for the purpose of arriving at a fair and equitable adjustment of values of all real and personal property, including such property of railroad and canal companies as contributes to the common cause.