1. a) No person shall cause or allow the emission of smoke from any diesel locomotive in the State of Illinois to exceed thirty percent (30%) opacity.

2. b) Subsection (a) shall not apply to:

   1. 1) Smoke resulting from starting a cold locomotive: for a period of time not to exceed 30 minutes.
   2. 2) Smoke emitted while accelerating under load from a throttle setting other than idle to a higher throttle setting: for a period of time not to exceed 40 seconds.
   3. 3) Smoke emitted upon locomotive loading following idle: for a period of time not to exceed 2 minutes.
   4. 4) Smoke emitted during locomotive testing, maintenance, adjustment, rebuilding, repairing or breaking in: for a period of time not to exceed 3 consecutive minutes and an aggregate of 10 minutes in any 60 minute period.
   5. 5) Smoke emitted by a locomotive which because of its age or design makes replacement or retrofit parts necessary to achieve smoke reduction unavailable. These locomotives shall be retired at the earliest possible time.

(Source: Amended in R90-20 at 16 Ill. Reg. 6184, effective April 7, 1992)