Transport: Rail
Locomotives

THE TECH THAT MAKES GE'S NEW LOCOMOTIVE ITS CLEANEST EVER

Burgess COMMENTARY

Peter Burgess

THE TECH THAT MAKES GE'S NEW LOCOMOTIVE ITS CLEANEST EVER


The GE Evolution Series Tier 4 Locomotive in testing on the plains of Colorado's Front Range.VINCENT LAFORET/GE

FREIGHT TRAINS DON'T get much love, or thought at all, really, from the general public. Most people rarely see them, even fewer put serious thought into what they're up to. But they're out there, and they're vital to the economy.

Rail accounts for 40 percent of US freight transport by ton-mile, with trucks accounting for just under 30 percent. Rail moves 70 percent of the nation's coal shipments, 58 percent of raw metal ores, and 30 percent of its grain. The $60 billion industry spreads over 140,000 miles of track.

And at the head of all of those trains are diesel-electric engines. And much like it has done with passenger cars and trucks, the US Environmental Protection Agency set its sights on the rail industry to regulate improvements in emissions. This kind of engine burns diesel to generate electricity, which powers traction motors and makes the wheels go. It's a gigantic chunk of machinery, and, because it hauls enormous trains weighing millions of pounds at 70 mph or more, it's running at full load much of the time.

The most recent batch of regulations was finalized in 2008, and the latest step—called Tier 4—went into effect this year. The goal is to cut particle emissions by 90 percent and nitric oxide and nitrogen dioxide (NOx) emissions by 80 percent, compared to 1992 levels.

General Electric, which accounts for roughly two-thirds of new locomotives in the US, has the first Tier 4-compliant diesel-electric locomotive in the country. The aptly-named 'GE Evolution Series Tier 4' has been in the works for half a decade, the result of a half billion-dollar R&D effort to meet the EPA's aggressive goals.

'We looked very hard at what it would take to reduce [pollutants],' says Ed Hall, senior general manager for Engine Engineering at GE. 'How we manipulate the fuel, manipulate the air, control the whole combustion process. We were able to do it.'


The GE Evolution Series Tier 4 Locomotive on the test loop in Pueblo, Colorado. VINCENT LAFORET/GE

Older diesel engines used a urea-based after treatment to scrub engine exhaust before it was released into the air. It worked, but required bulky add-ons to the engine, and required railroads to install extra infrastructure to get urea into the trains as well as the fuel. GE's railroad customers asked it to avoid the after treatment process if at all possible.

In 2010, GE's engineers broke into two teams to 'compete' on a viable solution. They came up with a method to control particulate matter and NOx within the engine itself, without any after treatment. This saves the railroads significant amounts of money on urea-treatment infrastructure, and results in a cleaner burning engine.

GE credits much of the advance to increased computer control within the engine itself. 'Really, the beauty of the thing is in the control,' says Mike Anderson, Tier 4 engineering leader at GE. 'The hardware technology is one thing, but the ability to control that hardware' and handle tons of tiny sensors, was key to meeting the EPA's Tier 4 requirements. The massive engine has 50 sensors to measure things like valve control, fuel air mix, engine speed, manifold temperature, and load, and manipulates fuel and air throughout the combustion process accordingly. That level of precision improves efficiency, ensuring the engine meets both the emissions and performance requirements for the train.

Another key development here is the variable speed auxiliary system. In effect, the engine can control how much power is flowing to the fans, battery chargers, blowers, lights, computers, etc. By fine tuning those different components, as real-time load on the engine varies, the Tier 4 engine can become even more efficient.

Life gets easier for the engineer, too. A few years ago, GE developed an autopilot system called Trip Optimizer, which controls the throttle and brakes based on the route, elevation changes, and the size and type of the load, all in the name of efficiency. If the train needs to slow down for traffic ahead, or make weather-related changes, the computer automatically recalculates the route and continues optimizing. Without the need to manage how the train's moving minute-by-minute, the engineer can pay attention to what's going on outside the cab. The system can improve fuel use by as much as 14 percent depending on the route. For an industry with slim margins like railroads, that can make a big difference to the bottom line.

The Test Track

The first prototype of the Tier 4 engine rolled out in August 2012, followed by a number of field test locomotives that GE tested on its test tracks later that year. This year, the company took its production-grade locomotives to a technology test center in Pueblo, Colorado. There, the engineers simulated long-term railroad operating conditions on 9- and 13-mile loops, with loaded cars running at high speeds for long periods of time. The huge loops of track and the high-altitude, reduced-oxygen environment gave the GE team a chance to see exactly how well the engine really works. Today, 20 preproduction engines have been delivered to customers, where they're being used to pull freight and provide last-minute feedback to GE before serious production begins later this year.

The Tier 4 locomotive is designed for a typical lifespan of 25 to 30 years. It's the best GE can make right now, and they think it will be viable through at least 2023. 'This will be our crown jewel product for the next eight years,' says Hall. The EPA hasn't said if there will be a Tier 5, but if there is, it should be right around when GE will be ready to launch whatever comes next. The Evolution Series Locomotive - GE

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