Lordclane
Chieftain
Once you've built your land completely over with railroads, there's not much for them to do, other than occasional conversions of land from one use to another. It would be nice if they had something to do... perhaps, using the future technology paradigm, they could make "further improvements" to existing improvements, increasing money return, production, or food (depending on what was being improved)....
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The manual tedium of clearing pollution was the worst. 
and
to the city. It would be great if it could provide power as well... but there are no other examples of upgraded tiles doing anything like that, making me wonder if it is feasible. 