An industrial museum in Sussex which had been put up for auction has been bought along with its entire stock.
George Stephenson's Locomotion model was among the exhibits
The British Engineerium in Hove announced its closure and put its contents on sale after trustees could not continue funding the operation.
Moments before an auction on Wednesday, Sussex entrepreneur Mike Holland bought the collection to keep it together.
Last month he teamed up with another businessman to save a Sussex independent school facing closure.
Mr Holland and John Summers, who both have children at Newlands School, put up £2.5m between them last month to keep it open.
Engineerium founder Dr Jonathan Minns said about Mr Holland: "I'm beginning as I know him to learn of the immense numbers of very important philanthropic things he's done in the community.
"His view was a sort of impatient, decision-making view saying it's complete intellectual madness to break up the engineerium - so bong, it's done."
Bonhams said a "substantial undisclosed figure" had been paid for the items, which have been on display for 32 years.
The chairman of Bonhams, Robert Brooks, said: "This is one of the finest collections of its kind in the world and we are thrilled that we have been able to keep it together.
"This is undoubtedly the best outcome for our client and for the country."
First railway engine
The Jonathan Minns Collection dates back to the industrial revolution and includes steam engines which powered trains, boats and hot-air balloons.
Dr Minns, a expert in the field of Mechanical Antiquities, founded the Engineerium but funding problems forced him to close it earlier this year.
The collection consisted of 489 lots, including engines used to power hot-air balloons, boats and trains, as well as a horse-drawn fire engine.
One of the highlights was a model built by George Stephenson of Locomotion No.1, the engine used on Britain's first railway in 1825, which Bonhams estimated could have sold for up to £75,000.
It has not yet been confirmed whether the collection will remain open to the