service or maintenance of rolling stock, right of way and/or stations at pre-COVID-19 service billing levels in such amounts as existed on February 3, 2020, even if such service was reduced due to the COVID-19 public health emergency: Provided further , That the preceding proviso may only apply if a contractor continuously retains its full and part-time workforce at their previous full or part-time status, and/or, where applicable, beginning on the date that employees of the contractor are able to return to work at their previous full or part-time status that it laid off, furloughed or terminated as a result of the COVID-19 public health emergency, or its effects, under the terms of any applicable collective bargaining agreement: Provided further , That private providers of public transportation may be considered eligible sub-recipients of funding provided under this heading: Provided further , That unless otherwise specified, applicable requirements under chapter 53 of title 49, United States Code, shall apply to funding made available under this heading in this Act, except that the Federal share of the costs for which any grant is made under this heading in this Act shall be, at the option of the recipient, up to 100 percent: Provided further , That the amount made available under this heading in this Act shall be derived from the general fund and shall not be subject to any limitation on obligations for transit programs set forth in any Act: Provided further , That not more than one-half of one percent of the funds for transit infrastructure grants, but not to exceed $125,000,000, provided under this heading in this Act shall be available for administrative expenses and ongoing program management oversight as authorized under sections 5334 and 5338(f)(2) of title 49, United States Code, and shall be in addition to any other appropriations for such purpose: Provided further , That such amount is designated by the Congress as being for an emergency requirement pursuant to section 251(b)(2)(A)(i) of the Balanced