The rates, tariff and taxes are subject to change and the company cannot be held liable for any such change. If at any time, during the continuance of service, the performance in whole or in part, of any obligation under it shall be prevented or delayed by reason of war, hostility, axe of the public enemy, civil commotion, sabotage, fire, flood, explosion, epidemic, strikes, lockout or act of god, etc, no claim for damages against the company in respect of such performance or delay in performance of the service can be claimed.