What are the minimum vertical clearances for model trains – British standards

Model Railway Standards

Don’t run the risk of having your trains crash into tunnel roofs. Build to British standards for minimum vertical clearance and train heights and keep your models safe.When building tunnels and over bridges for model trains to pass through making sure the train can pass through clearly without crashing in the top of the structure is obviously vital.

How high should a bridge or tunnel be for N, OO, HO scale?

Luckily, a set of standards that define this were devised in 1950 and if you keep to these you (or more importantly your trains) will be safe.

The standards are from the British Railway Modeling Standards Bureau and give exact dimensions for all the main British scales.

From track to train top these are:

N (1/148)




For reference, the protocol height (that of real trains) is 13ft.

So when planning and building a tunnel or bridge, measure from the top of the track rails to, say 54mm in the case of OO gauge, and go above this and you’ll be good.

Personally, I’d also allow a little extra room for access should you need to get your fingers or tool under there for whatever reason, not that our trains ever derail in tunnels… 🙂

As a final note, the history behind model railway standards, the British Railway Modeling Standards Bureau  – my copy of one of their publications is seen above – and the hobby and the History of OO Gauge part 1, part 2 and part 3 by Stephen Siddle is fascinating reading.

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