The thread about preserving polished side rods got me thinking. What parts on a in-service locomotive have to remain unpainted or clear coated.

You have side and main rods, piston rods, couplers, axles and ?? Diesel and freight car wheels are unpainted, but that doesn't seem to apply to steam locomotive wheels.

What am I missing.

Greg

Interior parts, of course. Probably fireplace grates, flues or stoker screws weren't painted. (But I am sure you refer to exterior parts.)

Piston rods remain unpainted because the gland that seals them against steam depends on very close metal-to-metal contact (if you are using metallic packing) Any paint there would rapidly be scraped away!

Same with the crosshead contact areas -- multiple-bearing crossheads have all the ledges internal, but the lateral bearing areas of alligator crossheads would need to be kept 'paint-free' for proper alignment.

It was my strong impression that driver tires had to be left unpainted, so that any cracks or damage would be immediately evident -- this was one reason fancy white tires stopped being applied to passenger power. This requirement may have changed with the advent of better portable NDT methodologies. (I have always wondered about the health hazards of tires striped with lead-bearing paint that were applied and removed with those gas-ring heaters!)

One-piece wheels are left unpainted to show cracking, which can be devastating on such wheels. I remember how awful the first-generation Amfleet cars became, in short order, when their extremely visible wheels turned into orange and brown spin paintings -- it took a while for them to 'patinate'. I'd presume that any such wheel applied to steam locomotives in retrofit would have the same requirement... but having been wrong already with respect to driver tires on new-built steam, I hesitate before claiming anything for engine and trailing truck wheels.

piston rods and moving parts where surfaces eventually touch something usually are lubricated, thats the protection they get. You cold paint up a coupler but you know action and shock is going to fling paint off. Steam I believe gets an interior oil inducted into its pathage to lube the cylinders. Correct me on this some engines may have this others not.

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I haven't seen couplers mentioned so far. Those on freight cars are required to remain unpainted, so I suspect that same requirement would carry over to locos.

Engine-tender drawbars.

As far as I know the FRA requires all couplers that are in use to be unpainted to make it easier to spot cracks.

Aren't the bright red painted drive wheel centers we see on foreign locomotives painted so that cracks will be more visible?

Steve

> I have heard the rumor floating around of how reproduction steam locomotives
> would be required to have one piece driving wheels without tires.

Recent go-'round of this rumor is probably attributable to me. It came from discussions of steam in the '80s, more specifically revolving in some way around the eight-drivered version of the ACE locomotive, with respect to the need for very regular underfloor lathe equipment. The argument was made then that 'modern' steam power was going to be subject to the FRA requirement of one-piece diesel/electric locomotive wheels.

I have subsequently been assured this isn't an issue, and I so state now.

And I happily add paintable tire rims to the list of permissible items on modern steam. Thanks, Kelly!