An archive of 12,000 pictures from one of "Britain's best railway photographers" is being digitised at The National Railway Museum.
Taken by Bishop Eric Treacy over about 40 years they are mostly in black and white and feature steam locomotives and the men who worked on them.
He was taking railway pictures at a station in Cumbria when he died in 1978.
The museum said Treacy's pictures were "of a way of life that's now entirely gone".
Ed Bartholomew, lead curator at the museum, said: "Eric Treacy was one of Britain's best railway photographers.
"His evocative images successfully capture our long-lasting fascination with the power of the steam railway, both in its heyday and declining years.
"They weren't just excellent records of the locomotives and rolling stock, but of a way of life that's now entirely gone."
The camera-clicking cleric was born in 1907 in London but most of his photographs actually feature northern scenes.
He became a deacon in the Church of England in 1932, served as an army chaplain in World War Two and rose to be the Bishop of Wakefield before retiring in 1976.
It was after the war that Treacy moved to Yorkshire and took many railway pictures in the county.
His favourite subject was the Settle to Carlisle line, often amid the scenery of the Yorkshire Dales.
Ian Beesley, an acclaimed photographer, said: "I know his work and early on in my career he was an influence as he photographed around Yorkshire.
"He was meticulous in his pictures and had a set style, he was like a collector and interested in the details of the things he shot."
Treacy died suddenly in 1978, appropriately enough at Appleby Station in Cumbria while photographing the locomotive Evening Star.
A plaque on the station commemorates him as a "lover of life and railways".
British Rail named an electric locomotive after him in honour of his contribution to railway photography in 1979.