560 tonnes of new rail, 7,000 new sleepers and 20,000 tonnes of new track ballast is being stored ready for the modernisation work, which will see the Metro's longest line closure for more than 30 years.
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The colours red, white and blue have been projected onto the monument following yesterday's terrorist attack at Westminster.
After Wednesday's downpours things are looking more settled.
Durham PCC, Ron Hogg is urging members of the public to "stay strong and stay together" by sharing intelligence to defeat terrorism.