Ah I wouldn’t stress…one will come at one stage or another, as the A class did eventually…
And now with suitible rolling stock ready for it (NIR mark 2s, bullied triangulated chassis wagons, Park Royal’s, 6 wheel coaches and so on) compared to when the B121 and A class locos were launched when every early 60s bit of rolling stock had to be kitbuilt, scratchbuilt, converted or those Bachmann coaches from years ago!