If at any time the whole of the working, management and maintenance of a railway, or of a specific portion or section of a railway, is assumed by the Armed Forces of the Union, the Central Government may notify the fact of such assumption in the Official Gazette, and thereupon, so long as such assumption continues, the Indian Railways Act, 1890(9 of 1890), shall cease to be applicable to the Railway or the portion or section of the Railway concerned.