The line achieved a major reduction on transport costs in the northern coalfield. It now cost Brayton Colliery 4 shillings per waggon to transport their coal to Maryport by railway, when road transport had formerly cost them 9 shillings per waggon; Gilcrux colliery were now paying half the 7 shillings per waggon road transport had cost them. At that time Whitehaven coal was being sold to the shippers at 16/6 delivered on board. Output from the northern coalfield increased rapidly, and with it the tonnage of coal shipped from Maryport. In 1842, the general manager of Whitehaven Collieries reported "The promoters of the Maryport & Carlisle Railway had the avowed object in view to injure Whitehaven, in which they have been successful". By 1846, almost as much coal was being shipped out through Maryport as through Whitehaven.