I always wonder what are the differences in track clearances or loading gauge between the European and North American model railroads (and also in reality). Visually the American locos are larger and taller compared to its European counterpart. This photo (HO models) shows that.
For those who want to run both the North American and European models on your layout, these measurements will help you. If you are sticking to European (or American), then it is good to know what the other side of the Atlantic have (just to satisfy your curiosity)
The above dimensions did not take into account the variable heights of the pantograph, which can be up to 40mm from the top of the rail. More vertical space should be allowed for the height of the tunnel especially where there are catenaries.