SGN have said that they have stopped the gas leak and made the 'situation' safe at the site near London Road.
In their latest update they said, "We’re continuing to carry out emergency repairs to our gas main in London Road, Salisbury, which was damaged by a third party yesterday.
"Our specialist engineering team has just now finished completing a very complex operation to make the situation safe and stop gas leaking from our network.
"However, the railway line between Salisbury and Andover will remain closed until we’ve finished carrying out essential safety checks. Only after these important checks are complete, can the railway line safely re-open.
"There are also two mobile phone network masts within our cordon which are currently turned off to ensure everyone's safety.
"We once again apologise for the inconvenience this is causing and continue to work as quickly and safely as possible to resolve the situation.
"All being well, we hope to complete safety checks later this evening."
Check theSouth Western Railway website for information about train journeys from Salisbury: www.southwesternrailway.com/plan-my-journey