I have been doing some research for my forthcoming Gresley book (shameless plug over) and have come across a real historical oddity! I have a document entitled Use of Engine Power. This covers 1942-1946 for the LNER's locomotive fleet. I have been organising a part of my spreadsheet version of this document into a whole-line average for the different classes, when I noticed this: A quick check of the LNER encyclopaedia here reveals this is the only class J7 listed: https://www.lner.info/locos/J/j7.php These were all gone by 1936 according to the LNER Encyclopaedia, RCTS Green Books, and pretty much any source I have that lists them. So I thought - okay, hands up - I've made an error in the spreadsheet when copying across. Except, I haven't. Here's a snippet from 1946 where class J7 is clearly given: One single locomotive of class J7 working in the SE part of the LNER. So here's the thing. Knowing how these records were collated, I am forced into thinking that there are a range of potential "truths" A surviving loco has been put back into service. How likely is this? Not very given it would be 10 years since they were all supposedly scrapped Another loco has been mis-identified. This seems more likely, but if it's a one off locomotive, then to add it into the statistics specifically as J7 seems unlikely. J7 has been used to describe another class, possibly from another region. I can find no record of any 0-6-0s being loaned to the LNER, but they did loan the GWR some J25s Have I missed an historical quirk of the LNER somewhere here? Where and what was class J7 in 1946? Answers on a postcard...!