I think there's been a thread on this before, but I can't find it; which examples have there been of TOCs operating networks which don't have any stations in common? I'm asking as the Tyne and Wear Metro closure between Monument and Pelaw means that the Metro currently fits that definition.
Other examples I can think of are South Western (no rail between the Island Line and the remainder of the system) and the London Overground (Liberty / Upminster – Romford and Weaver / Lea Valley lines not having any Overground stations also served by other Overground lines). This might be a short list either way, but I'd count temporary / engineering work closures as well, such as Northern's north east services being separate from everything else during Tyne Valley closures.
Other examples I can think of are South Western (no rail between the Island Line and the remainder of the system) and the London Overground (Liberty / Upminster – Romford and Weaver / Lea Valley lines not having any Overground stations also served by other Overground lines). This might be a short list either way, but I'd count temporary / engineering work closures as well, such as Northern's north east services being separate from everything else during Tyne Valley closures.