Enginner help limits?

[Father Beast]

I am playing a game right now where I send a spy or two out periodically into enemy territory to drain off my excess income buying engineers. I put these guys to work transforming all my land. I have somewhere around 70 engineers working for me, all but 4 of them supported by NONE.
The question is about stacking. I have engineers working in massive stacks, the highest being around 18 engineers on one square. But I'm wondering if I've reached a limit to whether more engineers helping helps at all. I haven't actually kept track, but it seems as if my stack of 8 is getting things done as fast as my stack of 18.
Is there a limit?

[Gatekeeper]

Father Beast:

IMHO, the answer is yes. In my experience, the maximum number of settlers/engineers one can have stacked to speed improvements is no more than 4. Typically two to convert a road to railroad in a turn, and two to turn irrigation to farmland in a turn (and so on down and up the Civ improvements ladder).

Anything more than that is just bait for the AI to attack .

CYBERAmazon

[Paul]

It is my experience that no more than 2 engineers can work on the same square on the same task. Only with transforming land I believe you can have 3 engineers working on it.

[SCG]

well, the obvious upper limit is how many turns it takes for an engineer to complete a task, and other than terraforming via the 'o' command, that usually is much less than 18. Somewhere buried, either in the strategy forum or this one, I seem to remember seeing a thread (i think by Xin Yu) about how he terraformed something in 1 turn (no preworking). I haven't tried it myself, and I know I'll never find it using the computer I'm on right now. But, IIRC, it involved deactivating finished engineers after the next one started its work, so that no more than 2 engineers had that 'o' on them at any 1 time. There also seemed to be a catch about when to have which engineer start the work and a further catch about how to deactivate them. Anyway, If you don't really want to go to the trouble of all that, stick to multiple small groups. I find that more efficient anyway, especially when doing stuff like increacing the food potential of celebrating cities.

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April Cantor: Sire, in order to expand further we must first gain favor of the King

SCG: darn, I've never really got the hang of that tribute thing, guess it will be a long time until i make prince

*goes off and starts gifting gold and techs*