Wow. They must have had wrenches and other passable hand tools as well. How in the world could they get that far, without managing to build and harness even rudimentary steam engines?

If someone had described Hero's aeolipile to the people who built this plumbing, it might have made all the difference.

I believe metallurgy was a serious issue for any possible Roman steam engine.

Still, a stationary power plant would have eminently doable in my not so humble opinion. Even stone for cylinder offers great compression strength. Make it big enough and the scale works out to your advantage. Bronze bearings could be made very durable.

The reason is simple - Romans tended to use wood as fuel source. Steam engines started way after we decided to use coal instead.

The wood heat is too low to get high pressure saturated steam, and lower pressure is not that useful and requires a huge boiler or specially prepared wood briquettes.

Metallurgically, Romans knew of brass and copper, which is enough for a decent steam boiler. It would be rather expensive to make.

You should check out Pompeii, a historical fiction novel by Robert Harris. The main character is an engineer responsible for waterworks.

Amazing! Lead is unfortunately malleable.

In 2000 years, they may say it of "plastic".

If you want more they found a four cylinder piston powered bilge pump in a roman wreck.

> four cylinder piston powered bilge pump in a roman wreck

Thanks for a tip! While I couldn't find exactly what you mentioned, I did find this picture of a bearing from a Roman bilge pump:

http://www.bbc.co.uk/ahistoryoftheworld/objects/0ZUWbEmiTXWf...

I tried finding a source online but google sucks for things like that now. But it's in a book I have on ancient technology.