In Minhag Ashkenaz, people do not wear the tallit gadol for Tish'a B'av Shacharit. I don't recall if this is a universal rule that applies to everyone, or if it is OK for those involved with certain parts of tefillah to do so.
For example, does the shat'z wear it? Do the Torah reader and those receiving aliyot wear it? I thought, perhaps there is an exception for "kavod" or similar reasons.