https://www.hk01.com/%E7%A4%BE%E6%9C...9B%9E%E6%94%B6
A quick summary by a local railway forum via Google Translate
Red economic circle running at full steam.MTR responded to the increase in vehicle purchases, stating that they intend to purchase new cars to replace the existing Tung Chung Line and Airport Express trains, but did not respond to independent tenders, but instead increased their purchases with the CRRC four years ago.