Last year's autumn floods may not be the worst to be seen in south Wales, especially if worldwide climate change is indeed under way. But they were certainly the most damaging seen so far by even the most experienced rail maintenance workers. According to the Environment Agency, the Welsh floods were the highest recorded in the region for 70 years.
So what lessons have been learned about rail maintenance in such adverse conditions?
Maintenance contractor for the south Wales region is Amey Rail, although a new bid is being made for the contract. The company runs the division as part of its Great Western maintenance operation.
Amey Rail divisional manager Lee Jones says Railtrack Great Western Zone is using information gathered from last year's flood to review the flood contingency plan it issues each year.
'The document highlights bridges with supports perhaps susceptible to scouring and those at risk from water pressure and damage from floating objects at high water,' says Jones.
'Railtrack is also reviewing its schemes to strengthen supports against the possibility of scour, and bridge beams and decks at risk during flooding. Talks between Railtrack and the maintenance teams are proving invaluable in planning for future flood events.'
Jones says physical inspections are the key to keeping the lines open for as long as possible before water levels become critical.
'This is where the experience of local managers and maintenance crews becomes vital as only they know which rivers will flood first and how fast the waters will rise in each valley.'
Monty Eaves is Amey Rail's Pontypridd section manager. His area of the south Wales rail network includes the branch line between Aberdare and Pontypridd, which flooded and was closed between 22 and 27 October.
'Trees could be seen floating down the line at the height of the flooding. We have experienced floods before, but this was exceptional,' he reports.
'This event confirmed what we have learned from dealing with floods in the past, particularly the importance of being prepared for the worst and communicating effectively with members of staff to keep them informed of what is going on.'
Local knowledge of the area and past experiences helped anticipate the worst of the floods last year and avoid trains becoming stranded, Eaves adds.
'Knowing that water levels can rise by up to 1m/h after heavy rainfall, we sent maintenance teams out as soon as the amber flood warning was given and closed the line as soon as we received news that the rain was set to continue.'
Large areas of the rail network flooded, or were at risk from bank slips, ballast erosion and damage caused by fallen or floating debris.
Some areas of central and southern Wales were hit worse than others and parts of the rail network flooded repeatedly as the rain varied in intensity but persisted throughout October. This resulted in maintenance crews visiting some sites on more than one occasion and even posting lookouts to keep a permanent eye on the worst trouble spots.
Amey Rail maintenance crews are benefiting from the company's efforts to identify local priorities with Railtrack.
Infrastructure performance director Tony Lindsay says data from all incidents of flood damage or train disruptions has been collated to establish programmes of preventative maintenance and work likely to result from future flooding incidents.
'We have established an infrastructure data room with Railtrack at our Swindon headquarters. Called the Campaign Room, it is being used to generate a visual display of track quality and performance standards using scale charts,' says Lindsay.
'The information is enabling us to plan maintenance strategically, and with regard to flood damage mitigation we have gathered sufficient data to show which areas are at greatest risk and where our attentions will be focused in the event of further floods.'