If you’ve seen numbers like 0-4-0, 2-6-2 or similar describing a steam or model railway loco and wondered what they mean, this is for you.
The number sequences, such as 0-4-0, are a notation system describing how many wheels a locomotive has and their role. It’s used on both full size and model trains.
Whyte Notation format and definition.
It was created in the early 20th Century by a Dutch born American engineer, Frederick Methvan Whyte, whose name the notation is known after.
The format for Whyte Notation is x-y-z.
- x means the number of weight carrying wheels at the front,
- y denotes the number of driving (powered) wheels in the middle, and
- z relates to how many weight carrying wheels are at the rear of the loco.
So for an steam locomotive with four main drive wheels would be classified as 0-4-0 while an loco with two leading four wheels in front, three driving axles and then one trailing axle (two wheels) being classified as 4-6-2. The train pictured above would be 2-6-2, two front wheels, six main drive wheels and two at the rear.
In Britain, the notation was expanded after steam engines were replaced with further letters giving the nature of the locomotives power. D or P is appended for diesel or P, with each followed by a letter revealing the type of transmission – E for electric, H hydraulic, M mechanical. So a six-wheel diesel locomotive with electric transmission would be 0-6-0DE.
Previous Model Railway Factoids: #1 The First Model Railway#2 The world's longest indoor model railway track
#3 The Smallest Model Railway
#4 The World's largest model railway
#5 Whyte Notation
#6 Origins of Ballast
#7 Everything You Could Want To Know About Sleepers
#8 The Biggest Model Railway Mountain #9 The Man Who Built 600 Model Trains
#10 Model Railway Eras - A Question Of Time
> 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.
