@RKX Technically, CIE having been formed in 1945 , all liveries of the 121 delivered in 1961 would be CIE. The original yellow and grey livery initially had a flying snail, no handrails, side vent on the body, tablet snatcher etc and this was placed in stages several year later by the Black n Tan livery some of which had handrails or none as they were gradually added. After 1972 the super train livery began to appear on the loco gradually as they were serviced/overhauled over the years following. Grey & yellow usually ran singly whereas (sometimes) BnT & superrtain would run in multiple with each other or 141s
Supertrain livery in consist with side handrails, side vent between the 129s over the bogies, body vents on the engines covers, hand rails, tablet snatchers still in place , original small marker lights (replaced in the 2000s with LEDS) window on the 'back' overlooking the bonnet side of the cab) still in existence
Photo Jeremy Chapter Flickr
BnT livery, no side handrails on B127 (yet) most other things per the loco above except this this has sand filler boxes on the 'rear' of the bonnet (nearest that coach) that were removed at various times (not on ST livery above)
Brian Flannigan Flickr (1971)
122 in ST 1987 (just before IR livery introduced)
Neil Smith on Flickr