The closest I've been able to find are Japanese-prototype Shibata couplers from Kato and Tomix, which look more like Scharfenberg couplers than N-2-A. They're quite a bit oversized in Japanese HO (1/80), and the Tomix and Kato couplers don't seem to be compatible with each other so you'd need to pick a brand and stick with it. For subway cars and light rail, you might be able to use their N scale versions as stand-ins for HO Tomlinson couplers.