Yeah I think that's probably what would happen if the X3 was cancelled. The East Boldon corridor would need more than a half hourly service, maybe 9 up to every 15 or 20 minutes, and the 26 running to Heworth or beyond instead.

I've used the 26/X3 connection in the past, and sometimes it's very easy to miss it. The tight connection may put people off travelling this way. The M1/X1 connection works well at Washington Galleries because both services run up to every 10 minutes so it's not too bad if you miss it, plus you're indoors too. A half hour wait at Boldon ASDA isn't ideal really.