This is fascinating and kudos to @seagoebox for recording it. Mac’s influence clearly rubbed off! Be interesting to know what names applied in steam days. 111 was always known as ‘The Sergeant’, for instance. Some ‘class’ names were applied. Thus PPs - and presumably the similarly equipped Ps - were known as ‘the wee bouncers’ because they had coil and not leaf springs. SG3s were, famously ‘Big Ds’. I have heard V class referred to as ‘Pounders’ but this may be an early usage as the name doesn’t seem to have percolated through to the late 50s.