also: サブウエーシリーズ
noun
Subway Series
Refers specifically to the interleague baseball series between the New York Yankees and the New York Mets, named after the city's subway system. Used as a proper noun in Japanese sports reporting.
今年のサブウェーシリーズはヤンキースが勝ち越した。
The Yankees won this year's Subway Series.
サブウェーシリーズはニューヨークの夏の風物詩だ。
The Subway Series is a summer tradition in New York.
Borrowed from English 'Subway Series', referring to the New York City subway system connecting the two teams' home stadiums.