§ 191. Road not to be constructed upon ground occupied by public buildings or in public parks. No street surface railroad shall be constructed or extended upon ground occupied by buildings belonging to any town, city, county or to the state, or to the United States, or in public parks, except in tunnels to be approved by the local authorities having control of such parks. Provided, however, that the commissioners of the state reservation at Niagara, by and with the consent of the commissioners of the land office, may construct, without expense to the state, street railroad tracks upon and along that part of the riverway, so called, between Falls and Niagara streets, in the city of Niagara Falls, and in their discretion may grant revocable licenses to street surface railroad companies to use such tracks upon such terms as said commissioners may prescribe. And provided, further, that a street railroad may be constructed or extended upon a route or routes with a right of way not exceeding fifty feet in width in the Pelham Bay park in the city of New York, said route or routes to be designated and fixed by the board of estimate and apportionment of said city, with the approval of the park board of said city, and shall constitute the most direct, appropriate route or routes in the opinion of said board of estimate and apportionment and said park board, but no such street surface railroad shall be constructed or extended until a franchise or right therefor shall have been granted by said board of estimate and apportionment, pursuant to the statutes relating to the granting of such franchises or rights, and requiring adequate compensation therefor, and no company or corporation shall be given the exclusive right to operate a street surface railroad upon such route or routes, and no such street surface railroad shall be constructed at grade upon, along or across any of the existing or proposed streets, highways, driveways, parkways or park walks within the limits of said park.