When corporate activist Bill Ackman staged his corporate coup at Canadian Pacific Railway Ltd. in 2012, one of his key goals was to install former Canadian National Railway Co. head Hunter Harrison as chief executive officer at CP, and get him to replicate the cost-cutting prowess he showed at CN. Since he came on board at CP in mid-2012, Mr. Harrison has led a cost-reduction drive aimed at trimming the key "operating ratio" – the closely watched efficiency indicator that measures costs as percentage of revenue. The numbers show his success: CP's OR has fallen dramatically from north of 80 per cent when he took over to just over 60 per cent.