Well the title speaks for itself. In this mod when a player drives the train, no matter the scale of it, the height of the player's position never changes. This is why some trains are unusable when not used on the standard scale.
Then my question is if it is possible to modify it or not, because it would be a shame to have real-sized trains but not drivable.

Here is a comparison between a standard scaled train and a brunel scaled train.

Here is a view from the cabin of a standard scaled train. Nothing unusual.

And finally the view of a cabin of a brunel scaled train. As you can clearly see, well there is nothing to see... The only way you could know where is the train going is to look at the sky, and even this requieries a great orientation skill.

The solution to this problem would be to add a way to adjust the height of the player inside the train, to be honest it would be useful even in other situations than this one.
Either way if someone knows the solution to my problem in any way then I am open for suggestions.