(4)The publication of a time table under which, or the giving of any direction that, any journey or part of a journey is to be completed within a specified time shall, if in the opinion of the Court it is not practicable in the circumstances of the case for that journey or part of a journey to be completed in the specified time without infringing the provisions of section 71, be prima-facie evidence that the person who published the time table or gave the direction has committed an offence punishable under sub-section (2).