Network Rail engineers and mining specialists are working to repair a railway tunnel damaged in the recent storms.
The Conwy Valley line between Llandudno Junction and Blaenau Ffestiniog is likely to be closed until mid-November as a result of the damage to the tunnel near Blaenau Ffestiniog.
Railway maintenance staff inspected the tunnel after ex-Hurricane Ophelia and Storm Brian and found a structural pillar inside was found to have suffered damage from the excessive rainfall which had caused more water than usual to enter the 140-year-old structure.
Engineers are undertaking detailed assessments and developing designs to repair the damage. A team are on site preparing to start the demolition and reconstruction work to the pillar and surrounding rocks.
In addition there are other areas along the line that require repair works following the storms.
A Network Rail spokesperson said engineers are working to reopen the tunnel by mid-November.
She added: “Our engineers are currently repairing the damage caused to the Blaenau Ffestiniog tunnel during Hurricane Ophelia and Storm Brian. The Conwy Valley Line will remain closed whilst this urgent essential work takes place.
“We understand the railway is a vital link for local people, however safety is a key priority, and we are working hard to get the line reopened as soon as it is safe to do so.
“We are working closely with Arriva Trains Wales, to keep passengers moving during the closure of the line, and a rail replacement bus service will be in operation until it reopens.
“We will continue to keep passengers and the local community informed while this essential repair work is completed.”
Liz Saville Roberts, Plaid Cymru MP for Dwyfor Meirionnydd, said: “I am deeply concerned that the Conwy Valley railway line into Blaenau Ffestiniog has been closed to carry out emergency repairs in the tunnel.
“The railway link to the mainline and Llandudno is a lifeline for the town, and I am contacting Network Rail for an update as a matter of urgency.”
The tunnel, at two and a half miles long, is the longest of its kind in the UK.
It is the second time this year the line has been caused as a result of bad weather.
In February the line was closed for several weeks after Storm Doris caused a tree to fall on the track near Pont-y-Pant.
Engineers had to move over 300 tonnes of rock and fallen vegetation during the recovery work.
The line was previously closed in December 2015 for seven weeks after the track was damaged by floodwater in more than 100 places following heavy rain on Boxing Day.
Previous flooding in 2004 and 2005 also resulted in prolonged closures whilst the trackbed and embankments were rebuilt.
The 2004 floods closed the line from early February until late May.
