(05 Apr 2015, 12:34 pm)ifm001 wrote Yes. When the x20 and x50 were introduced they both ran south shields to Durham using ex OK travel optare deltas 4801 to 4805 excluding 4802 which wasn't at same depot. They thenCurtailed the x20 to do Sunderland to Durham only but always interworked with x50
Thanks for the information, it's something that has always fascinated yet confused me.