610 ILCS 20/1
That every railroad company organized under any law or laws of this state, in force before the first day of March, A. D. 1872, is hereby empowered from time to time to borrow such sums of money as may be necessary for completing, furnishing, improving or operating any such railroad, and to issue and dispose of its bonds for any amount so borrowed, and to mortgage its corporate property and franchises to secure the payment of any debt contracted by such corporation for the purposes aforesaid; but the concurrence of the holders of two-thirds in amount of the stock of such corporation--to be expressed in the manner hereinafter provided--shall be necessary to the validity of any such mortgage; and the order or resolution for such mortgage shall be recorded as provided in this act; and the directors of such corporation shall be empowered, in pursuance of any such order or resolution, to confer on any holder of any bond, for money so borrowed as aforesaid, the right to convert the principal due or owing thereon into stock of such corporation at any time not exceeding ten years after the date of such bond, under such regulation as may be provided in the by-laws of such corporation.
610 ILCS 20/1