I had the pleasure of getting to know 138 a couple of days back. Unlike most preserved locos these work really hard and it shows in the condition. It looks good from a distance but closeup the red paintwork has faded irregularly and there is oil, grime, coal dust everywhere. Most of the copper paintwork is discolored from the heat and surprisingly battered and dented. Steps, handrails etc are mostly shiny bare metal. The trouble is if you weathered one accurately no-one would believe it.
I was also pleasantly surprised how much the track has mellowed with even some grass in places. Wonderful.
John