Royal Canal traffic in 1844 (Salt)
That table is extracted from Samuel Salt’s Statistics and Calculations essentially necessary to persons connected with railways or canals; containing a variety of information not to be found elsewhere 2nd ed Effingham Wilson and Bradshaw & Blacklock, London 1846, available from Messrs Google here.
The interesting point is how little of the Royal’s traffic travelled the whole way from the Shannon to Dublin or vice versa: only about 5% of the Dublin-bound traffic and less than 3% of the traffic westward.
Another point of interest is that traffic to Dublin was three times the traffic from Dublin.
Amongst the livestock, pigs were the dominant animals: they lost too much condition if they were walked long distances, which was the only alternative to canal transport before the railways came. Even there, I suspect that much of the tonnage described as “from Longford and the Shannon” was actually from west of the river, in Counties Mayo and Roscommon.
Irish waterways history 