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Trains are not running on several lines today due to ice blocking power supplies.
Freezing conditions overnight have resulted in a build up of ice on the lines between Ashford International, Dover Priory and Canterbury East.
As a result Southeastern cannot run services between Minster and Ashford International, Sandwich and Ashford International; and Dover Priory and Canterbury East.
Network rail said the tracks were treated last night to stop this happening but rain washed anti-freeze away leaving rails coated in ice.
"Ice is an insulator, unlike water, and creates a barrier between the live rail and the trains, stopping them from drawing power," a spokesman said.
"In extreme circumstances the trains can even weld themselves to the live rail or become stranded.
"While we have conductor rail heating fitted at key locations in Kent when an entire area is blanketed with sleet like this, it's still not safe to run trains until we've re-treated the tracks.
"Unfortunately, disruption like this happens when sleet or snow falls after we've treated the tracks, but before trains are running regularly.
"All we can do is send the treatment trains out again and get things moving ASAP.
"Once again, please accept our apologies.
"And please take care, as conditions are slippery all over East Kent this morning."
De-icing is taking longer than expected and services won't be back fully until after 5pm.
With more wintry condition tonight, Southeastern is expecting delays to continue into tomorrow.
In its latest statement, the rail operator said: "Because of the current wintry conditions, and with more snow forecast overnight tonight, there is a risk of disruption to Southeastern train services on Monday, particularly early in the morning.
"So that Network Rail can check that the rails are clear of snow and ice, which can prevent trains from drawing power from the electric rail, the first trains in each direction on many routes are likely to be cancelled.
"Southeastern strongly recommends that passengers check before they travel and if possible, travel a little later.
"Journey planners will be updated with details of any cancellations as soon as they’re confirmed."
On Friday, the Met Office issued a yellow weather warning for snow and ice from 6pm tonight until 9am tomorrow and said it could cause disruption through to Monday.
It comes as Southeastern launch their new timetable.
Separately Southeastern and Thameslink can't run trains between Charlton and Dartford in the north of the county after a person was hit by a train.
It is impacting the Woolwich Line and Greenwich Line.
But Southeastern hopes the lines will reopen from midday.
Tickets are being accepted on local London Buses, DLR, Underground and Elizabeth Line.