Passenger rail · Western United States
A locomotive fleet running below its certified target
11.4% below target
What does it mean when a locomotive fleet reads below its certified combustion target?
Across 16 EMD 16-645F3B locomotives with 0 OEM fault codes present, fleet CO₂ averaged 6.55% against a 7.39% certified target, 11.4% below the line. Below target is a power finding, not a pass: an engine under its certified target is not making its rated power. A separate horsepower measurement put the average shortfall at 494 HP against a 3,600 HP specification.
A commuter rail operator in the western United States. Across 16 EMD 16-645F3B locomotives, fleet CO₂ averaged 6.55% against a 7.39% certified target, 11.4% below the line, with 15 of 16 units below and a single unit above. Reading below target is not a clean bill of health: it is the signature of engines not making their rated power. The same fleet showed an identified horsepower loss averaging 494 HP against a 3,600 HP specification, 14% of rated. Two independent measurements, one finding. The certified baseline came from the operator's own certified test of unit 7 in March 2016.
0 OEM fault codes present. Across 16 EMD 16-645F3B locomotives, 15 of 16 reading below the certified target.
Common questions
Reading this case, answered.
- What does a fleet reading below its certified combustion target mean?
- An engine running under its certified combustion target is not making its rated power, so a low reading is a finding rather than a pass. On this fleet 15 of 16 units read below the certified target and a single unit read above it. A separate horsepower measurement put the average shortfall at 14% of rated, which is the same conclusion reached a second way.
- Where does the certified baseline come from?
- The certified baseline for this fleet came from the operator's own certified test of unit 7 in March 2016. Every engine is compared against its own certified baseline rather than an industry benchmark, so the comparison is specific to the equipment being measured. That is what makes a below-target reading a finding about these locomotives rather than a general observation about older rail power.
- What engines does the method cover?
- Emissions-Based Maintenance is OEM-agnostic. Its baselines are calibrated against 32,000+ EPA-certified engines from 200+ manufacturers, spanning model years 1996 to 2027 across EPA Tier 2 through Tier 4. It is validated across Caterpillar, Cummins, MTU, EMD, and John Deere engines, roughly 150 HP to 3,000+ HP, so it fits the mixed fleet in the yard today.
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Fully telematic ingestion, zero manual probes