Robert Napier, 67, nonchalantly placed the priceless heirloom in the overhead compartment, but when he got off the train at his stop, he had his coat and briefcase, but no violin, The Daily Mail reported Tuesday.
"It was the first time I had been on one of the new, fast trains … and as I got off I was just thinking about the train and whether it would fit on the platform. I just wasn't thinking about the violin," said the grandfather of two.
Napier called the police and rail officials, who promptly had the train searched at its next stop, but they found no trace of the violin.
The violin in question is a 1698 Matteo Goffriller. The master craftsman made instruments for some of the most renowned classical musicians, including Nicolo Paganini.
Napier's mother, Elizabeth Hunt, bought the Goffriller for her service with an all-women's quartet that played at military bases during the Second World War.
The Mail said the Goffriller is in a brown case with a tag bearing the name Elizabeth Napier and its bow is stamped "R Sartory."