OOP: Wizard's robes

[rose_in_shadow]

No: HPFGUIDX 65229

Minor 

Spoiler

pace

For 

OotP

I suppose it is movie contamination but I've always pictured the 
wizarding robes as a coat-like garment. But, as we now know from 
Snape's Pensieve scene, the robes are, apparently, a set of clothing 
with nothing worn under them except... erm... the nesecaries. :o)
 
This is actually rather alarming as it states in several of the books 
that the Trio changed *into* their robes on the train. I don't 
suppose there is a changing room on the Hogwarts Express? Or did JKR 
simply forget this fact of her characters' clothing?

~Moira