RCMP say the accident happened around 10:30 p.m. Monday just north of Niton Junction, about 160 kilometres west of Edmonton.
They say 10 out of 60 cars that were carrying stone left the tracks and spilled their cargo, but no one was hurt and no roads were blocked.
The freight was not carrying any hazardous goods and no waterways were affected.
CN is sending workers to the site to get the cars back on the tracks and clean up the scene.
The accident comes as the cleanup continues at the scene of a derailment involving a Canadian Pacific Railway (TSX:CP) freight in Banff National Park last Friday.
Material known as fly ash was in some cars that jumped the tracks into 40 Mile Creek near the Banff townsite.
Parks Canada has said that all but one of the cars has been hauled out, but the challenge is to ensure that spilled material isn't disturbed before it can be removed from the icy creek.
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