Introduced in 1936, ICI required these wagons to transport limestone from quarries in the Peak District to Northwich for the production of various chemicals. This was the first 'block freight' train running multiple times a day with a purpose built wagon to maximise the flow of the goods. Originally worked by LMS locomotives, in BR days most medium to large steam classes based in the North West were to be used on the flow including everything from the 4F to 9F.  Most diesel classes have been recorded hauling them as well with classes 20, 24, 25, 28, 31, 37, 40, 45 & 47 all being used at some point.  The wagons lasted just into the 2000s with the last being scrapped in 2001, being replaced by a mix of new build and re-purposed wagons on flows around the country.