Question: Black Forest, South Australia is bounded by the railway line that is a commuter line in what city?
Sentence (from "Keiyō Line"): The line forms part of what JR East refers to as the "Tokyo Mega Loop" (東京メガループ ) around Tokyo, consisting of the Keiyo Line, Musashino Line, Nambu Line, and Yokohama Line.
Relevant evidence: No