It should be
Poor old man was crossing the road when along came a
Wheel barrow
fish and chip cart
Trolley Bus wire wiper (needs explaining these days!)
Corporation car what sucks water out of holes
Shiny silver spittled silver shaddow (Rolls Royce)
Double decker bus with babies singing (you can add "the wheels on the bus go round and round" to make it more complicated.
Bicycle wheel that went rolling down the hill

and ran over the poor old man!