Bruce Reynolds claims the person responsible was a friend of Jimmy White, who they had recruited for a previous job to be extra muscle. Reynolds himself was not at the train site as he was the spotter at the Ledburn road rail bridge and met the gang at the rendezvous point at Bridego Bridge after Mills was forced by Goody to drive the train. He describes "Alf Thomas" as "a big old boy, very reliable, and would have been useful for the money train" (their practice job) "because he had the muscle to disable the police cars by tipping them over before we sprayed them with fuller's earth and compressed air." ("Crossing The Line", 1995, p. 178.)