Native English speakers, could you please help me with these issues?

Question

Are both these sentences correct (and do they mean the same):

a) "The chat room is always run by a teacher for a period of 4 hours, who afterwards was replaced by another teacher for the same LENGTH OF TIME, and SO ON."

b) "The chat room is always run by a teacher for a period of 4 hours, who afterwards was replaced by another teacher for the same LENGTH OF TIME, and SO SUCCESSIVELY."

Answer 1

Favourite answer

For a period of four hours, the chat room is always run by a teacher who afterwards IS replaced by another teacher for the same length of time, and so on.

Answer 2

The chat room is always run by individual teachers who change over at the end of successive 4-hour shifts.