(20 Jul 2015, 2:14 pm)South Tyne Lad wrote Its not rare as most boards interwork with X4/X5/X10/X11s, Though im not sure if anything interworks with the X13.
They don't interwork, the 308 is standalone, the X4 is standalone, the X5 is standalone and the X13 is but the X10/X11 could interwork.
However Blyth often send out a spare bus to keep the services on time hence the odd workings.