Should any street surface railroad company have crossed any bridge as a part of its route for a period of more than five years and should any other bridge be substituted therefor at any time, such company shall have the right to cross such substituted bridge and to lay and use tracks thereon for the transit of its cars and to make all changes and extensions of its route subject to all the provisions of this chapter, as the convenient operation of its cars and public convenience may require.
New York Legal Code