While many of us were sprawled on the sofa watching TV or recovering from hangovers, teams have been ripping out tracks to improve the rail system.

Over the Christmas and New Year holiday, gangs were rebuilding Lewisham junction which should make it easier - strikes permitting - for Kent commuters heading towards London.

Network Rail said yesterday (Saturday, Dec 31): "We are in the final days of a major project to rebuild the complex and busy Lewisham Junction. This project is important for southeastern passengers."

It added: "Lewisham is so complex and busy that we've had to approach the challenges from both angles. We need to have the infrastructure running as near perfect as possible."

In a series of Tweets with photographs provided by contractor Colas Rail, it set out the work which has taken place over the past eight days.

It said: "In the early stages of any track or junction replacement, after disconnecting power and signalling, we rip out the old rail, sleepers, and ballast. The vast majority of the old materials will be recycled.

"Special matting and new ballast are laid to form the new track bed. We used more than 6,300 tonnes of new ballast for this job.

"The railway signalling, power supply and rails are only as good as the track bed they sit on.

"Wet beds, when the ballast falls away, can cause track instability leading to signalling, communication and power supply faults. This has been a big problem at Lewisham up to now."

It went on: "Once the track bed is laid, it’s time to install the rails and sleepers. Panels are prepared off-site, brought in via engineering trains and then lifted into place by a Kirow crane.

"Eighty-one panels were lifted in at Lewisham, the heaviest weighing 28 tonnes.

"It was like a massive jigsaw puzzle. And while the pieces are very big and very heavy, we needed to be very precise. We work to millimetres as any discrepancies with the track alignment could, in a worst case scenario, cause a train to derail.

"When the pieces of the puzzle are in, it is time to connect them all up. Multiple teams of welders have been working on 200 welds.

"This will ensure trains can travel smoothly over the junction and people living nearby will hear less noise.

"When the rails, signalling, power supply and other components are reconnected, it is time to tamp. Tamping is the railway equivalent of fluffing a pillow.

"Again, it's about ensuring we have a stable and smooth track bed.

"Southeastern passengers will be all too aware of how any incident at Lewisham can lead to congestion and delays rippling across the entire network. This work is another step towards making this section of railway more reliable."

One commuter replied: "I'm grateful and thankful that Network Rail has found the time and money to do this project. Also to the men and women who gave up their Christmas to do it.

"But let's be honest, if southeastern was serious about running a timetable to remove congestion, it wouldn't just reduce off-peak services."

Although services should be back to normal tomorrow (Monday), the next two-day strike by Rail, Maritime and Transport Union members (RMT) starts on Tuesday. They will also be striking on Friday and Saturday in a dispute over pay and conditions which has been running since the summer.

On all days of action, trains will start later and finish earlier than usual, running between 7.30am and 6.30pm.

National Rail said: “The rail industry is working hard to minimise the effect that this will have on services but it is inevitable that services will be cancelled or severely disrupted. It is likely that there will be a very limited service on these days with no trains at all on some routes.”

It warned there may also be "some disruption" to services on Sunday as members return to work.

More RMT strikes involving more than 40,000 rail workers at 14 major operators are planned in January.

A separate 24-hour walkout organised by train drivers represented by Aslef will be held on Thursday. It includes workers at 15 operators and is likely to shut down most of the rail network.