The coupling rods of a shiny new GWR dock tank (1366) posing for its portrait at Swindon in 1934.
Look at a picture of a real loco and the rods are usually brighter than everything else, though not necessarily shiny. Well, if the rods are plain metal and everything else is painted black, that makes sense. In some pictures of new, clean locos, the rods appear almost white as if they were made of, say, aluminium. It doesn't help that most pictures of steam locos are monochrome.
Its sister (1367) a little later, still clean but now at work.
So, assuming that coupling rods are made of steel, that they are stored and work out of doors, are subjected to sporadic covering with hot steam and cleaned only occasionally, what colour are they? My answer would be grey/blue and oily, with a touch of rust.
Preserved pannier 4612 in 2007.
Colour photos of preserved locomotives don't help. They all seem to be dedicated to preserving the myth(?) of bright rods. In any case, this doesn't tell us what a typical working (but presumably well-kept) loco looked like in 1935.
When I use blackening salts on nickel silver rods, I find that the blackening tends to rub off easily in some places, leaving a mottled, uneven finish. To me, this looks realistic, but doesn't resemble any photo I have seen of a real loco.
Blackened Nickel Silver rod.
I have a tin of Humbrol 'authentic colour' enamel labelled 'HS 217 Steel' which is a silvery grey/blue colour. Maybe I should paint the rods with that, but I doubt whether they would look realistic. How about crossheads and slide bars?
An almost new 1850 class pannier outside Paddington in 1935 with the rods all but invisible!.
Is this realistic?