Video report from ITV News Meridian's Mike Pearse
Thousands of railway workers are half way through a massive upgrade of the regions rail network at almost four hundred locations.
Many have given up spending Christmas and New Year with their families to maintain and improve track and signals on key routes from Kent, Sussex, Hampshire, Surrey and Berkshire to London.
Major work includes the lines from Kent and Sussex fo London Bridge and Charing Cross. Work at major stations is also taking place at Victoria and Waterloo.
Upgrades are also taking place on the lines through Southampton and Eastleigh and the route from Waterloo to Reading.
The work is costing tens of millions of pounds with some staying in hotels to ensure the keep Covid secure.
It started late on Christmas Eve and continues until the end of the New Year break with passengers advised go to check train times as many may have changed.