The engine rotates the cogwheel attached in the Workshop even when the game is closed. It doesn't need energy to rotate. You can upgrade it to make it spin the cogwheel faster.
To change the position of the the engine, pres--and-hold it until the "drag" button appears.
It produces vapor, which is collected by the Vapor collector
| Level | Cost | Effect |
|---|---|---|
| 1 | +1 Engine | |
| 2 | +1 Engine | |
| 3 | +1 Engine | |
| 4 | +1 Engine | |
| 5 | +1 Engine | |
| 6 | +1 Engine | |
| 7 | +1 Engine | |
| 8 | +1 Engine | |
| 9 | +1 Engine | |
| 10 | +1 Engine |