Cogenhoe was involved in the extractive industries. Digging for iron ore began at Cogenhoe in the late 1850s with opencast quarrying and mines – the latter of which, according to local lore, collapsed one lunchtime while the men were away having their midday meals. The mines were for whatever reason opened out in about 1868. The quarries continued up the hill towards the Firs. These quarries were connected to the main London and North Western Railway in the valley by way of narrow gauge and standard gauge private branch-lines. The narrow gauge line was cable worked taking the ore down to a tipping dock on the standard gauge branch. In about 1870, the operation moved west with a standard gauge line running through what is now the Pocket Park to the Ironstone field south of the Playing Fields. A short narrow gauge branch always worked by hand or horses connected that quarry to the standard gauge branch. The standard gauge line was originally operated by gravity and horses, the loaded wagons coasting down the gradient from the western end of the line to just south of the road near Roe Farm. However steam locomotives were introduced in 1880 or shortly afterwards.