Allister Boote paid more than £30,000 for the huge Cowans Sheldon crane but is now reached a deal with the railway after learning how crucial it is for the operation.
Mr Boote successfully bid for the crane at an auction of the assets of the Llangollen Railway Plc, the operating arm of the tourist attraction, which went into administration earlier this year owing £350,000.
The railway trust, which is not in financial difficulties, had raised enough money to buy vital rolling stock to keep the railway going but did not have enough funds for the crane.
Mr Boote had intended to transport the crane to the Sandbach Commercial Dismantlers Company he and his sons run in Cheshire to break it up and sell.
But when he travelled to Llangollen to discuss its dismantling and removal, he realised how much it meant to the railway.
"I could see just how devastated the people at Llangollen were and how hard they were working to keep the railway going," he said.
"I realised I could do something to help them."
Mr Boote's father, who started the family company, 40 years ago, had been a fireman/stoker on steam trains, based at Alsager near Crewe.
"He would not have wanted to see the railway lose such a valuable asset," he said.
"We have been told that it had originally been a steam crane in the Second World War and was converted to diesel to work on the railways."
He had talks with the members of the railway trust and between them they reached a deal.
"The crane will remain at Llangollen," he said.
"There may be a crowdfunding scheme to help replay the money we paid but also we will collect the scrap that the railway has. Every time we pick a skip up that will go towards repayment.
"We would not have been in a position to do this 20 years ago but we are glad we can help.
"The trust has made us honorary members of the railway and invited us to go and visit. As I have grandchildren we are very much looking forward to travelling on the trains when the railway reopens in the summer.
"I am sure my father would be proud of what we are doing."