And we've been proven right, as steam enthusiasts have been in touch to give us chapter and verse, and we have had a bonus in the fascinating tale of how in 1952 the young new Queen stayed overnight in a train parked up at a disused railway station in deepest south Shropshire.
While we knew the picture was taken at Wellington railway station, Nick Waters of Shrewsbury turned to his steam buff friend Malcolm Jones to find out the exact details.
Malcolm told him: "I knew I had a picture of this in my collection. It is in my 'Craven Arms to Wellington' book about country railway routes and, as a true anorak, I need to tell you that the picture is of 4406 about to work the 4.30pm to Much Wenlock in July 1950. The loco to its right is LNWR 0-6-2 No. 58904 with the 3.53 to Coalport (east)."
And Ken Brothwood emailed in: "I believe the photograph is taken in the early 1950s.
"This particular locomotive is heading a stopping train on what was referred to as the Much Wenlock branch line. This line originally continued onto Craven Arms where it joined the main line between Shrewsbury and South Wales.
"The locomotive in question was certainly allocated to Wellington shed (84H) in late 1951. The adjacent line was the platform for stopping trains to Wolverhampton."
It was Bridgnorth's Chris Magner who chipped in the story from the early months of the Queen's reign.
Chris said: "Congratulations to the Shropshire Star for the magnificent photo of former GWR locomotive No 4406 at Wellington Station on a Much Wenlock, Harton Road to Craven Arms train taken sometime between 1949 to 1951.
"The last passenger train from Much Wenlock to Craven Arms ran on Saturday December 29, 1951 and the former GWR 44XX class locomotives worked on that line.
"The Much Wenlock to Craven Arms railway has one big claim to fame. Her Majesty the Queen, when making her first trip to Wales on October 23, 1952, spent two nights at Harton Road Station.
"The Queen has stayed at many places around the world but she is the only monarch who can claim she stayed for two nights at Harton Road, which served Eaton-under-Heywood, near Church Stretton, and I gather parts of it are still used as private accommodation."
Chris says that there were certain sections of track, sidings, or lines in strategic places that could berth the royal train at night for when there was to be a royal visit, and they tended to be in remote locations for security reasons, giving the little Shropshire station its moment of glory.
"I cannot prove this but there is a possibility that the track from Marsh Farm Junction to Harton Road was deliberately kept from lifting knowing the forthcoming royal visit. Someone once wrote the monarch has stayed in many country houses and locations and they have a plaque to say she stayed there. What a pity there was not one put up at the site of Harton Road Station.
"To the best of my knowledge the Queen left London Paddington via Shrewsbury about 10pm and arrived at Harton Road about 2am to 3am, leaving for Wales about 8.30am. After a full day visiting Wales – the first by the new Queen – she returned to Harton Road about 7pm, went to Shrewsbury for a function the next morning, before returning to London.
"While at Harton Road she probably did not leave the warmth of the royal train, but who knows?"
Chris says the Queen's Wales tour caused controversy.
"Railwaymen on the Craven Arms to Swansea Victoria line were fiercely loyal to the LMS railway. It caused much upset to them that instead of using former LMS locomotives, the Western Region used two 'Castle' class locomotives to haul the royal train.
"This was the only time in the 150 years of the Central Wales Railway that 'Castle' class locomotives were used."