Swiss Federal Railways (SBB) said it used buses on Sunday to replace regional passenger train service between Flüelen and Göschenen in the canton of Uri while crews cleared rocks from rails.
The rockslide occurred in the Amsteg/Silenen area of Uri at around 8pm on Saturday, the ATS news agency said.
An inter-city (ICN) train was stopped and 180 passengers were evacuated at Erstfeld, the agency said.
No-one was injured.
SBB advised train passengers travelling from northern Switzerland to Ticino and Italy to expect longer travelling time.
EC trains from Lucerne and Zurich to Lugano and Milan were rerouted via Bern and Brig, the publicly owned rail operator said.
Workers had to remove rocks from nets and on the tracks, repair damaged overhead wires and remove unstable rocks, SBB spokesman Rahel Meile was quoted as saying by the 20 Minutes newspaper.