Initially only freight trains will use the Gotthard route in central Switzerland, but passenger trains will start to operate from Tuesday morning, news agency ATS reported.
On average, 120 freight trains use the line every day.
Between 2,000 and 3,000 cubic metres of rocks fell at Gurtnellen in Uri canton at the beginning of June, damaging the track and halting international and domestic services.
Two workers were injured in the slide and one was killed.
Following the accident, train operator CFF redirected freight trains via the Simplon tunnel and laid on replacement buses for passengers, adding an hour to journey times.
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The cost of the disruption to the rail line is estimated at 10-20 million francs ($10.5-21 million), a CFF spokesman said.