Prior to sectorisation virtually every locomotive was painted blue. A number were later to get large numerals and the double arrow symbol - a move started with 56035.
73138 was one of these and this model was originally this loco in the appropriate box. However I recently obtained a Class 73 body in the guise of 73212 in the Gatwick Express livery - so this item is the loco chassis and two bodies - one 73138 in BR large-logo blue and the other 73212 in Gatwick Express livery. - when you get fed up with one livery you can just change the body - or impress someone by switching the bodies when they're not looking!