The discovery was made by Mike Swift, a founding shareholder in the Lincolnshire Coast Light Railway, which took over the running of the Scarborough North Bay Heritage Railway earlier this year.
Mr Swift had been asked to look for heritage photos of the railway in Lincolnshire for their archive when he came across the historic Scarborough photographs.
The detailed postcards show evocative scenes of pre-war holiday crowds enjoying a ride on the famous miniature line.
A booklet commemorating the railway's Golden Jubilee - published 40 years ago - was also uncovered.
The booklet was published in 1981 by Scarborough Borough Council, who ran the landmark attraction until it was sold in 2006.
John Kerr and Peter Bryant were announced as the new owners of the Scarborough heritage railway in March, which is celebrating its 90th year.
At the time the new owners said they were looking forward to working with a dedicated team to take the railway to its centenary and beyond.
It is thought there may be many more previously unseen photos from the early days of the Scarborough railway – particularly old family holiday photos tucked away in long-forgotten albums. Copies or originals will be particularly appreciated for the railways’ archives.
They also help to emphasise the significance of these lines in building the hospitality industries of the area, as many people rediscover the delights of holidays on the Yorkshire Coast during post-covid staycations.
Discoveries can be emailed to Chris Bates at [email protected] or posted via Skegness Water Leisure Park, Walls Lane, Ingoldmells, Skegness, PE25 1JH.