N.Y. Pub. Serv. Law § 114
To facilitate prompt action by the commission in proceedings involving the reasonableness of the rates of any public utility and to avoid delay in any such rate proceeding, the commission is hereby authorized to require any public utility company to establish, provide and maintain continuing property records, including a list or inventory of all of the physical property actually used in the public service, and to require any public utility company to keep its books, accounts and records in such manner as to show currently the original cost of said physical property and the reserves accumulated to provide for the retirement or replacement of said physical property.
The commission may, in any such proceeding, brought either on its own motion or upon complaint, upon notice and after hearing, if it be of opinion that the public interest so requires, immediately fix, determine and prescribe temporary rates to be charged by said utility company pending the final determination of said rate proceeding. Said temporary rates so fixed, determined and prescribed shall be sufficient to provide a return of not less than five per centum upon the original cost, less accrued depreciation, of the physical property of said public utility company used and useful in the public service, and if the duly verified reports of said utility company to the commission do not show the original cost, less accrued depreciation, of said property, the commission may estimate said cost less depreciation and fix, determine and prescribe rates as hereinbefore provided.
Temporary rates so fixed, determined and prescribed under this section shall be effective until the rates to be charged, received and collected by said utility company shall finally have been fixed, determined and prescribed. The commission is hereby authorized in any proceeding in which temporary rates are fixed, determined and prescribed under this section, to consider the effect of such rates in fixing, determining and prescribing rates to be thereafter charged and collected by said public utility company on final determination of the rate proceeding.
N.Y. Pub. Serv. Law § 114