During transit, the gold was held in "railway safes", which needed two keys to open. The men took wax impressions of the keys and made their own copies. When they knew a shipment was taking place, Tester ensured Burgess was on guard duty, and Agar hid in the guard's van. They emptied the safes of of gold, valued at the time at £12,000 (approximately ), then left the train at Dover. The police and railway authorities had no clues as to who had undertaken the theft, and arguments ensued as to whether it had been stolen in England, on the ship crossing the English Channel, or on the French leg of the journey.