One of the challenges beginners to model railways face is understanding scale and gauge and the relationship between them.
If you’re about to start building a layout this simple video will tell you what you need to know.
I’ve touched on the differences between scale and gauge before (see this beginners q&a) but still get a lot of questions about on the subject so here’s a handy video for those struggling to understand.
What’s unusual about this video — compared to a lot of others — is that it covers not just the main sizes — N and OO — but many others too.
Indeed, one of the questions about scale and gauge is that while N and OO are understood where do HO, HOe, HOn3, HOm, 0n30, 009 and O fit in?
This video explains all and also includes some nice footage of trains in these sizes running along with visual comparisons to coins to help.
Sit back and enjoy.
If you still have questions, see an earlier model railway beginners Q&A on the difference between scale and gauge or check out my scale calculator.
> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.

Andy is a lifelong modeler, writer, and founder of modelrailwayengineer.com. He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.
In the “The Difference Between Scale And Gauge – Beginners Guide” section . . . So, where’s the “handy video for those struggling to understand”? There’s no link to a video.
Hi Ray, have a look now. There’s a bug in the system I use that occasions ‘disappears’ the video’s. Thanks for bringing it to my attention on this article. Best wishes, Andy