I’ve been tinkering with various combinations while life is quiet... this loco will negotiate O42 but it definitely isn’t preferred. It’s happy enough on O48 (I tried it on a combination of fastrack O48 with O72 transitions and it seemed happy enough).
It doesn’t care for O42, although it would be ok over switches or in off-scene staging yards, but a combination of O27 size, O42 with O54 transitions seems to work well enough.