OO and HO gauge model trains are the most popular but can you run OO trains on HO track?
To answer this, it’s worth first recapping what these two main model railway standards are and the differences between scale and gauge.
HO gauge, the most popular size in Europe, are model trains with a scale of 1:87 or 3.5mm to the foot.
OO gauge, made famous by Hornby, are model trains with a scale of 1:87 or 3.5mm to the foot for track and a scale of 1:76 or 4mm to the foot for the locomotive bodies and other models on a layout.
You might ask why the scale for the models, the locomotives, people and buildings is different to the track, and that would be a very good question.
Simply put it, at the time OO was created, the most popular trains were in HO gauge. To maintain compatibility with these existing products – and so keep costs low – OO was designed to use HO width track. However, because British locomotives were smaller than European engines there wasn’t enough space inside the models for the motors at this scale so the bodies of OO gauge trains were made slightly larger at 4mm to the foot and it’s been like that ever since.
So can OO trains run on HO track?
Recapping on the explanation above, OO and HO gauge railways both have a track width of 16.5mm so the OO train will run on HO track.