TfL Plans to Extend London Overground to Stevenage via Hertford and Welwyn Garden City

Transport for London (TfL) has revealed plans to expand the London Overground network into the Home Counties, potentially extending services all the way to Stevenage.

The move is part of TfL’s new business plan, covering 2026/27 to 2029/30, which outlines key projects and spending priorities for the coming years. TfL aims to take control of the “inner” part of the Great Northern Railway network, creating a new Overground branch linking Moorgate with Stevenage, passing through Hertford North and Welwyn Garden City.

TfL says taking over the route would allow it to increase train frequencies, improve facilities, and boost reliability, while bringing the line into its smartcard ticketing system. The plan would also see stations on the route rebranded in the Overground’s signature orange colour, effectively redrawing the Tube map to reflect the new services.

The proposed expansion could unlock housing growth along the route, particularly in areas such as Crews Hill, where the plan could support 16,000 planned homes, with the potential for a further 17,000 properties.

Currently, the Overground’s northernmost stations are Cheshunt on the Weaver line and Watford Junction on the Lioness line, meaning this extension would significantly expand the network into Hertfordshire.

The Hertford branch also serves stations including Highbury & Islington, Finsbury Park, Alexandra Palace, Hitchin, and Letchworth, although some stops like Hitchin and Letchworth are only served during weekdays. Peak services from Moorgate currently run up to 10 trains per hour, with pre-Covid frequencies reaching 12 trains per hour. TfL plans to double off-peak services from two to four trains per hour by December 2026.

TfL has submitted a business case under the “right to request” system, with the aim of gaining government approval in the coming months. The proposal is designed to be financially neutral to the Department for Transport, with improvements funded through TfL’s operational budget.

The business plan also highlights other rail projects, including the DLR extension to Thamesmead, already approved by the government, and plans for a West London Orbital rail link, which TfL hopes to integrate into the Overground network.

Meanwhile, Govia Thameslink Railway (GTR), the current operator of Great Northern services, is preparing for renationalisation on 31 May 2026 under the government’s creation of Great British Railways. A GTR spokesperson said the company is working closely with the DfT during this transition, continuing to run safe and reliable services while introducing modern, air-conditioned trains and making station improvements such as at Enfield Chase.

TfL has also appointed a new operator for the Overground: First Rail London will take over from Arriva Rail Londonin May, promising more trains on two of the network’s six lines.

TfL emphasizes that the expansion of the Overground into the Home Counties would not only improve travel in London but also support sustainable growth, housing delivery, and more reliable rail services for passengers along the route.