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All trains between Strood and Maidstone West were suspended on Sunday morning after an electrical fault.
Operator Southeastern arranged for replacement buses while the problem was fixed.
Trains were back running as normal by midday.
A spokesman said at 9am: "Owing to an electrical power supply problem all lines [between Maidstone West and Strood] are blocked until further notice.
"Network Rail are working on the problem trying to restore it. In the interim Southeastern has arranged replacement bus services to cover that line but we do advise customers to check by calling 08457 484950 before travelling."