An elderly man has been charged after tens of thousands of dollars were stolen from a backpack on a Sydney train.

Police said about $40,000 had been stolen from a backpack on a train at Glenfield in the city’s southwest on Wednesday.

An investigation was launched, which led police to the home of a 74-year-old man on Bringelly Rd in Rossmore.

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Police allege the man found the backpack on the train, and moved the cash into his own bag before getting off the train.

About $36,500 in crash was recovered.

The man was charged with larceny and disposal of property.

He was granted conditional bail to appear before Campbelltown Local Court on July 24.