Updated Study Strengthens Case for Western Rail Link to Heathrow

A refreshed economic assessment of the proposed Western Rail Link to Heathrow (WRLtH) suggests the long-standing scheme is now more viable, citing reduced cost estimates, improved returns and increased potential for private sector investment.

The proposed link would connect the Great Western Main Line at Langley to Heathrow Terminal 5 via a new tunnel, making use of two existing but unused underground platforms at the airport.

Although classified as a Nationally Significant Infrastructure Project, the scheme has long been expected to rely in part on private funding—potentially led by Heathrow Airport, though other investors could also be involved. The project was paused in 2021 בעקבות the collapse in air travel during the pandemic.

The latest study, commissioned by the Thames Valley Chamber of Commerce (TVCC) with support from Transport for the South East (TfSE), indicates that the business case has strengthened under current conditions. Construction costs are now forecast to be lower, with efficiencies—particularly in tunnelling—identified as key drivers of savings.

The report also notes that passenger demand at Heathrow has recovered faster than anticipated, with 2025 figures already aligning with pre-pandemic forecasts.

Based on an assumed opening date of 2032, the scheme could begin generating returns by 2044. Under a two-runway scenario, the project is considered viable, though with more limited returns unless further cost reductions are achieved. However, if Heathrow expands to three runways—an option supported by current government policy—the financial outlook improves significantly, with an estimated internal rate of return of around 8.1% over 30 years, potentially rising to 11% under certain conditions.

The study proposes a mixed funding and delivery model, with a “split package” approach. Under this structure, the tunnel and Terminal 5 connection could be privately financed, while the grade-separated junction at Langley would likely be delivered by Network Rail using public funding.

However, the report suggests that full private financing of the tunnel section would depend on achieving sufficient investor returns—something more likely if a third runway proceeds.

TfSE continues to identify the Western Rail Link as a priority scheme, highlighting its potential to significantly improve rail access to Heathrow from the west, reduce congestion on surrounding road networks and support regional economic growth.

A second phase of analysis has been proposed to further refine the economic case and delivery options, helping to inform any future Development Consent Order (DCO) application—particularly in light of Heathrow’s expansion plans.

While the full report will remain confidential due to commercially sensitive information, summary findings indicate renewed momentum behind a project that has been under consideration for more than a decade.