Why don't old steam engines rust?

[nadroj]

Anorak Bob's recent posted photos of an old steam engine in Zagreb reminded me of something that puzzles.
I've seen large, ancient steam engines, sometimes still going. They have impressively large rods, links and other ferrous parts.
But, they are in beautiful, rust-free condition, often with a lovely satin like finish. Why is that?
You'd think that being old and primitive they'd be all be rotten.
Some guesses:
They are under cover, meticulously maintained and constantly cleaned.
There is always a lot of oil about, protecting the surfaces.
The parts aren't steel, but wrought iron - not so liable to rust.
They would be rusty, but have been restored.

I'm talking about the engines, not boilers which are clearly rust prone.

Jordan

[PDW]

Anorak Bob's recent posted photos of an old steam engine in Zagreb reminded me of something that puzzles. I've seen large, ancient steam engines, sometimes still going. They have impressively large rods, links and other ferrous parts. But, they are in beautiful, rust-free condition, often with a lovely satin like finish. Why is that? You'd think that being old and primitive they'd be all be rotten. Some guesses: They are under cover, meticulously maintained and constantly cleaned. There is always a lot of oil about, protecting the surfaces. The parts aren't steel, but wrought iron - not so liable to rust. They would be rusty, but have been restored. I'm talking about the engines, not boilers which are clearly rust prone. Jordan They most certainly do rust if left unprotected in the weather, so the premise of your question is incorrect. Having said that, cast iron rusts at a lot slower rate than mild steel in the same atmospheric conditions. PDW

[nadroj]

I doubt the parts in question are made of cast iron.

Jordan

[kwijibo99]

G'day Jordan,
I suspect the constant maintenance and cleaning carried out on a working steam engine is the main factor.
An abandoned steam engine will rust the same as any other piece of machinery but as 600W steam cylinder oil is one of the best rust inhibitors there is the deterioration may be slower.
Cheers,
Greg.

[Steamwhisperer]

Hi Jordan,
At the end if each run the engines are wiped down with an oily rag. The engine was always a reflection of the drivers standards.
We have restored many engines that were filthy and covered with dirt which has been it's saving grace. Dirt and oil is actually a great mix. Hot steam oil is fantastic as a preservative.
Some engines though have been wiped clean of oil and stuck outside which means a lot of elbow grease to make them shine again.

Phil

[cba_melbourne]

Who says they do nor rust?
324299
The ones in museums are regularly looked after.... think just of polishing off all these kids fingerprints...

Old steam locos still in service are very high maintenance, certainly when compared to elctric locos.

There are brand new steam engines though, manufactured today with modern materials and technologies. Made for mountain railways and narrow gauge etc, turists just love steam locos:
http://www.trainweb.org/tusp/slm.html

This is the Swiss company DLM, manufacturing new full size steam engines:
http://www.dlm-ag.ch/en/modern-steam

[nadroj]

That's not a great photo of the actual "engine" parts. The whole locomotive looks nice and weathered though.

I visited the old Goulburn pumphouse earlier this year. Took some photos, can't find them.
The large stationery steam engines are still going for the tourists' entertainment.
The working parts look like they could have been made in the last decade, not 1886.
Not a speck of rust to be seen on the crank rods, which are unpainted.
Maintenance and cleaning must have been challenging, as it was a 24/7 operation when it was pumping water for the town.

Jordan