Somerset Joins Castle Cary and Taunton in a Major December Rail Lockdown as Network Rail Shuts Key Route for Urgent Flood-Proofing Works

Published on December 1, 2025

Network Rail will carry out a major rail infrastructure upgrade in Somerset, resulting in a full seven-day closure of the line between Castle Cary and Taunton from 8 to 14 December. The works focus on essential drainage renewal near the Somerton Tunnel, a strategic section of track that connects London Paddington with key destinations across the South West. With long-distance, regional, and commuter services all using this stretch, the closure marks one of the region’s most significant planned engineering programmes of the winter.

A Critical Upgrade to Protect a Flood-Prone Route

The project targets a section of railway that has experienced repeated flooding, leading to delays and operational difficulties during heavy rainfall. To strengthen the resilience of the network, Network Rail is renewing approximately 600 metres of drainage along the line. The work is part of a national programme that aims to protect major routes from weather-related disruption, particularly during winter when the risks are highest.

The renewal involves large-scale material delivery, including 1,400 tonnes of ballast and 800 tonnes of shingle, which will help stabilise the track bed. Up to 25 engineers will be on site at any given time, working continuously to ensure the drainage installation progresses efficiently throughout the scheduled closure.

Additional Track, Signalling and Vegetation Work During the Closure

The extended closure period will also support several parallel maintenance tasks. Network Rail teams will inspect and test vital signalling systems, adjust track points, and clear vegetation along the route. These activities enhance overall operational safety and reduce the need for future disruption, as maintenance can be completed in a consolidated timeframe.

The shutdown around Somerton Tunnel allows all activity to be completed without affecting live train services. Once the route reopens, passengers will benefit from improved infrastructure and reduced vulnerability to flooding and seasonal conditions.

London to South West Services Diverted as Timetables Adjust

Train services between London Paddington, Plymouth and Penzance will be diverted throughout the engineering window. The diversion will add a minimum of 15 minutes to journey times as trains avoid the closed section of track. These revised routes ensure that essential long-distance travel continues throughout the work period.

A limited number of weekday services will continue to operate between London Paddington, Westbury and Castle Cary, maintaining vital connectivity across Somerset. However, passengers should expect altered timings and reduced frequency during the engineering period.

Bristol and Weymouth Services Unaffected Throughout the Upgrade

Passengers travelling on services between Castle Cary and Bristol Temple Meads or Castle Cary and Weymouth will not experience any disruption. These routes bypass the affected section near Somerton Tunnel and will continue to run normally. Maintaining these unaffected connections ensures regional travel across Somerset remains accessible during the works.

These uninterrupted services support commuters, leisure travellers, and local passengers who rely on stable connectivity across the West Country.

Replacement Road Transport to Support Passenger Journeys

To maintain essential travel links during the closure, replacement bus services will operate daily between Castle Cary and Taunton from 8 to 14 December. These buses will form the main connection across the blocked section and support passengers completing longer journeys across the Great Western network.

On weekends, additional replacement road transport will run between Pewsey and Swindon, providing onward connections for passengers affected by the adjusted rail services. All timetables and road transport arrangements will be visible through official journey planners, enabling passengers to track updates throughout the week.

Passengers Encouraged to Plan Ahead and Allow Extra Time

Network Rail and Great Western Railway advise passengers to check their travel plans in advance due to the adjusted schedules and diversions in place throughout the week. Journey planners and official service updates will reflect revised timings, extended routes, and replacement transport arrangements. Allowing additional time will help passengers navigate transfers and maintain onward connections.

The drainage upgrade near Somerton Tunnel forms a central part of Network Rail’s strategy to reduce flooding-related disruption and strengthen long-term network reliability. With winter conditions approaching, this work is critical for supporting smoother operations across Somerset, Castle Cary, Taunton, and major routes linking the West of England with London. Once complete, the improvements will enhance performance and help secure a more dependable railway for passengers travelling throughout the region.