No one seems to know why the numbers 150 and 151 were used. At the time Sheffield Transport used lots of numbers for short workings, so "odd" journeys on the Shiregreen estate could be 20, 24 or 75! Numbers were therefore in short supply but in 1938 there was a huge gap after 97 and 98 with only a few oddment numbers in the hundreds.
Indeed that route structure remains unaltered to this very day ...
Or does it?
Here the Greek Tragedy of fbb's ghastly mistake begins to inexorably unfold. Doom is inevitable.
Sometimes we do get to see a modern bus company using a very traditional livery.