How tall is a Lego train on a track?
LEGO tracks are 12mm high, train wheels go below the true height of the track and so in reality only add 7mm of height.
The structure gauge (also known as clearance) tolerance will obviously be a lot lower than real life. You could perhaps get away with 1/3 a brick clearance but having at least one or two bricks height clearance at minimum is best.
Here are a few measurements for different types of trains.




Model
Name
Studs
Centimetres
Inches





Amtrak Superliner
17.9
14.4
5.7



4551 (Pantograph extended)
16.3
13.1
5.1



Double-Stack Cart
12.8
10.2
4.0



Early Steam Locomotive
12.4
9.9
3.9




I have used Bricklink Studio to render and calculate these measurements. The models used can all be found in the model library.
Dimension and weight statistics for models can be displayed under Tools &gt; Mode Information so if you can find a model for the train you are interested you can check using this software.