71C. (1) The railway servant, other than the railway servant whose employment is essentially intermittent, shall not be employed for more than sixty hours a week on the average in any month.(2) The railway servant whose employment is essentially intermittent shall not be employed for more than eighty-four hours in any week.(3) Subject to rules made under section 71E, temporary exemptions of railway servants from the provisions of sub-section (1) and sub-section (2) may be made-(a) when such temporary exemptions are necessary to avoid serious interference with the ordinary working of the railway, in cases of accident, actual or threatened, or when urgent work is required to be done to the railway or to rolling-stock or in any emergency which could not have been foreseen or prevented; and(b) in cases of exceptional pressure of work not falling within the scope of clause (a):Provided that the railway servant exempted under clauses (b) shall be paid for overtime at not less than one and a quarter times his ordinary rate of pay.