Merseyrail Northern Line reopens after £3.5m tunnel works

Merseyrail's Northern Line fully reopened on Saturday 7 November after four weeks of work to strengthen and waterproof four tunnels under Liverpool city centre, Network Rail said. Trains ran between Hunts Cross and the city centre for the first time in 27 days.

The infrastructure manager put £3.5m into the Victorian-built tunnels between Brunswick and Liverpool Central. The aim is to keep water out of the structures, so that moisture does not interfere with the third rail that powers Merseyrail's electric trains. Liverpool Central is one of the busiest stations in the country, with more than 14 million entries and exits in 2024/25, according to Network Rail.

Since Sunday 11 October, more than 50 workers removed 92 m² of old concrete before new concrete was applied, and drilled 6,500 holes in the tunnel walls for waterproofing injections. A liquid resin is injected into the brickwork and sets into a waterproof barrier. Another 115 holes were drilled as weep holes to steer water into the drainage on the track bed. In total, 1,688 m² of tunnel wall were waterproofed.

The closure was also used for a second job. During four extended Sunday closures, power control systems were modernised across the Northern and Wirral lines. The work is part of a wider project to upgrade the track feeder switches, and their control rooms, that supply the third rail. Network Rail says this will make it easier to isolate and switch off sections of electrified rail, so that maintenance teams can work on the line and fix faults quickly and safely. Further upgrades will continue through 2027, mostly when trains are not running.

The two strands are linked. On a third-rail network, the conductor rail runs at track level, so water seeping through tunnel brickwork is more than a maintenance nuisance: it can cause electrical faults and disrupt services. Faster isolation of power sections also matters for safety, because staff cannot work on or near the third rail until it has been switched off. Neither Network Rail nor Merseyrail has published reliability figures for the line before the work, so the gain will only be measurable in the months ahead.

Stephen Dodd, Merseyrail's chief operating officer, said the upgrades would "strengthen the long-term reliability of the Northern Line and help reduce the risk of future disruption". Passengers will be told well in advance if further disruptive closures are needed, the company added. Readers following the cost of rail works in Britain can also see our analysis of the UK rail infrastructure costs review.

Sources: Network Rail, "Railway reopens after four-week £3.5m Merseyrail tunnel upgrades" (7 November 2026).

Photo: a Merseyrail Class 777 at Fazakerley, on the Northern Line, January 2023 — silver-novice, Wikimedia Commons, CC BY 2.0.

Article written with the help of artificial intelligence from the sources cited, reviewed by the TrainsNews editorial team before publication.