1) General subject: on the anvil, on the job, upon the anvil, being worked under, in the works
2) Military: in the mill (о документе)
3) Engineering: in service
4) Construction: in-use
5) Automobile industry: in work
6) Jargon: on the fire
7) Atomic energy: in use
8) Patents: when in use
9) Business: in hand
10) Automation: in operation
11) Makarov: in the pipeline
12) Gold mining: in progress
13) SAP.tech. in process
14) oil&gas: (скважина) (a well is) on production
Универсальный русско-английский словарь. Академик.ру. 2011.