There was no such thing as "School Busses", in my day (left St Illtyds in 1968)
When it moved to Llanrumney/St Mellons, the travelling pupils from Splott, Tremorfa, Roath and the such, were allocated bus passes.
The boys I used to travel with all had passes, as they were supposed to catch a bus to the Royal Infirmary, then a connecting bus to Llanrumney. Most of them didn't, they used to walk over Moorland Road bridge, meet me (I never had a pass), then catch the bus at the Royal Oak Pub (which I might add, is in ROATH)
Now here's the thing. We all used to try and catch the 44, which went straight along Newport Road and stopped outside the school gates.
Two other busses (can't remember the numbers), used to turn left onto Llanrumney Avenue, then one used to turn left again onto Ball Road. We would get off these busses at Countisbury shops and walk up Mount Pleasant Avenue.
Two other busses went through Rumney, into Trowbridge, but we tried to avoid these, as you had a gigantic hill to climb up, at the back of the school.
Boys I can remember on the busses are, Andrew North, John Houlston, Terrance O,Reagan, Peter Finn, The Nagle brothers, Ian Murphy, all these from Splott or Tremorfa