The Midland Railway opened the "Super Outer Circle line" in 1878. This was the outermost loop in London and the Midland Railway's main interest was supplying coal to Kensington, and in 1878 it opened coal depots around Kensington. Soon after, they ran a passenger service between St Pancras and Earl's Court, travelling via West Hampstead, Cricklewood and South Acton. This lasted until 1880 due to operation constraints, having served a twice-hourly frequency.