An elderly man is in a critical condition after being hit by a train in Adelaide.

Emergency services were called to Ovingham Railway Station, in the city's north, just before 9am, after a man was struck by a passing train at the pedestrian crossing on Devonport Terrace.

The 81-year-old was rushed to Royal Adelaide Hospital, and is in a critical condition.

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It's the second incident at the crossing, which due to be upgraded.

There is already work underway.

Warning lights were covered, and safety gates not yet in use.

It comes two weeks after a cyclist was hit by a train at a North Adelaide crossing, where works were also underway.

Both incidents happened on the Gawler line, where work continues after a $900 million electrification project.