Nigel Thornley collected the toy engines for more than 70 years after being given his first train set as an 18-month-old boy.
Over the decades he went on to build up an enormous collection of more than 300 model trains before his death earlier this year, aged 72.
His lifetime collection is now set to fetch tens of thousands of pounds at auction when it goes under the hammer at Hansons Auctioneers on September 11.
The "once in a lifetime" collection is said to feature an eclectic mix of locomotive models as well as postcards and train books.
Mark Holder, Hansons’ specialist in trains and railwayana, said: “This model train and railwayana collection is so large and comprehensive it deserves an auction all of its own.
"Nigel’s love of trains was all-encompassing and his passion comes through on every level. The collection could sell for £70,000 and deservedly so.
“There’s something for everyone, from fine scale O gauge and gauge 1 examples, with OO gauge and die-cast Dublo trains to postcards and a large cache of books.
"And if you like building your own models, there are unbuilt kits from manufacturers like DJH.”
Nigel, of Chester, also devoted his life to preservation of Britain’s railway heritage, according to his family.
Paying tribute, they said: “Nigel began his love of trains with Hornby Dublo 3-Rail track as a small boy.
"When he was 12 years old, he used to go to the local signal box and help out. On one occasion he got a warning the inspector was on his way, so hid round the back.
"But the inspector knew he was there, called him in and put him through his paces answering a series of questions about signal boxes and how they were used.
"He then got Nigel to demonstrate the correct way to operate the levers and signals. Finally, he said ‘the lad can stay’ - much to the relief of the signalman, and Nigel.
“At the age of 14 he used to be picked up by Richard Greenwood, a father figure in railway preservation, and taken to Haworth in West Yorkshire for the weekend to help restore a Pug.
"That Pug is still in service at Haworth’s Keighley and Worth Valley Railway. He became a founder member of the Keighley and Worth Valley Railway Society.
“In his late teens/early twenties he got together with his friend, Trevor Hughes, to form the Rochdale Model Railway Society which is also still thriving.
“His real passion was the Lancashire and Yorkshire Railway Society, and he became an avid modeller of engines, coaches and rolling stock and collector of anything he could find of his beloved L&YR.
"However, he still modelled and collected locomotives and stock from other lines too.
“He was fanatical about wanting to preserve things for posterity and, determined that nothing should be lost, he and his fellow society members worked with the Manchester Archives to ensure as much information as possible was saved and recorded there.
“He literally spent hours searching the internet for items which he then bought on behalf of the L&YR and sent to the archives.
"He was a member and supporter of many railway societies, heritage trusts and guilds and a regular face at exhibitions.
"He will be sorely missed by all who knew him.”