dive-under
noun1
Rail transport, Railways, Transport A railway junction where at least one track passes under other lines instead of crossing them on the same level, in order to avoid conflicting movements; an underpass.
- Services from Heathrow would use the existing Byfleet Junction, enabling trains to join the slow line of the South Western Main Line to Woking. The junction already has a dive-under.2019 November 20, “Government delays Heathrow rail to consider other modes”, in Rail, page 25: