Thunderbirds, from the T.V. series, are/were International rescue....... The 57/3's are Virgin rescue loco's (Thunderbirds) and they are modified class 47's. The Virgin class 57/3's, as in 57301 upwards to 57312 (I think!), are named after characters from the original Thunderbirds T.V. series....and "Lady Penelope" has her own pretty-pink addornment ;-))
Colin.