Differences between 途中 and 途上
I would like to know more about the differences between 途上 and 途中.
From examples it seems like 途中 can mean both 'on the way' and 'half way' (i'm seeing more examples for half-way though)
And 途上 appears to be mostly 'on the way'
Is this correct? What would the most commonly used choice for 'half way' and 'en route' be?