engine room

Short definition from Wiktionary

Noun

1. 1
   A compartment on a ship in which the engine machinery is located.
2. 2
   The source of power in a team or other group: The midfield.
3. 3
   The source of power in a team or other group: The pair of locks in a team.
4. 4
   The source of power in a team or other group: The front row.
5. 5
   The source of power in a team or other group: The rhythm section of a steel band.