"There were six of our volunteers working that day, and they were kept busy chatting to people the whole time."
Mrs Flynn said everyone from elderly people in wheelchairs to preschoolers was keen to see "the hero of the hill" -- as Engine H199 is known in Joy Cowley's picture book about the Rimutaka Incline.
Particularly special however, were the visitors who were connected with either the old railway or the tunnel -- such as one man who arrived wearing a red hard hat.
As it turned out, he was one of the last surviving crewmen who built the tunnel while living on the site of the old Featherston Military Training Camp.
"He was wearing the same hat he wore while working on the tunnel -- he'd kept it all these years," Mrs Flynn said.
"He was lovely, a real hard case.
"We didn't get his name unfortunately."
He was followed by a retired fireman, who worked on the steam engines travelling between Wellington and Summit Station.
He kept the staff entertained with stories of the crew of H199 he had met at Summit, most of whom have now died. Also attending was the niece of the late Jim Goggin, who had taken video footage of the steam engines on the Rimutaka Incline.
Before he died, Mr Goggin compiled his footage into a short film, Rimutaka 49, which is played at the Fell Museum on request.
Mrs Flynn said the open day attracted many new visitors, including several newcomers to Featherston, and a US tourist so taken with the museum he was determined to pay the normal entry fee.
"He couldn't put any change in the donation box, as he only had his credit card.
"I said he didn't have to, and he said 'I insist'."
Mrs Flynn thanked Midweek and Destination Wairarapa for promoting the event.