Penn State and Norfolk Southern Develop Battery-Powered Train
NS 999 is an entirely electric locomotive that uses a lead-acid energy storage system comprised of 1,080 12-volt batteries to operate in railroad switching applications without the use of a diesel engine and with zero exhaust emissions.
In September 2009, Norfolk Southern unveiled its NS 999, a prototype 1,500-horsepower switching locomotive that relies solely on rechargeable batteries for power. When the company set out to design and build this all-battery-powered locomotive, they had little experience with batteries and the assembly of battery plants. So the company needed a partner to help with battery research and testing. Gerhard Thelen, corporate vice president responsible for research and development, contacted Penn State’s College of Engineering, and with the assistance from the Industrial Research Office, representatives from Norfolk Southern spent a day meeting with faculty members and researchers.
“In that one-day visit, we were able to assess the abilities of Penn State researchers working in our particular areas of interest,” says Thelen. “We knew about the difficulties in managing the batteries properly so you don’t lose the life or create safety issues. In the visit we had, the researchers convinced us that through testing and modeling, they could come up with a duty cycle that would optimize the life and prevent any safety issues from occurring.”
Also, Thelen adds, because of the number of batteries in the locomotive (over 1,000) and the high cost involved, Norfolk Southern preferred that testing on charging and discharging the batteries was done in the lab first.
Thelen and his team are working with Chris Rahn, Professor of Mechanical Engineering, and Chao-Yang Wang, Distinguished Professor of Mechanical Engineering and Director of the Electrochemical Engine Center, one of the top fuel cell and battery research labs in the country. Partial funding for the collaborative research project comes from the U.S. Department of Energy.
Wang is researching battery systems, particularly looking into how many charge and discharge cycles can be achieved in locomotive operations. “It’s what we call cycle life,” explains Wang, “and that’s very important because that determines the life of the battery system, which is a very expensive component in the locomotive.” Wang’s research group has been conducting experimental testing and computer modeling to learn the battery cycle life and how to extend it.
Rahn’s role in the research is system dynamics. “My job is to develop the models to be used by systems engineers so they can analyze the system to see how it is performing—to predict the state of charge in the actual battery system, for example,” says Rahn. “One of the things we’re doing is developing a meter that will provide the status of every single battery in the system.”
The team has completed its first year of research and has received funding for a second year. “During that first year, we were looking at the actual batteries and testing under different concepts of charging and discharging,” explains Rahn. “And this will continue.”
They have good models that predict the performance of the batteries. The next step, Rahn says, is to look at those models in terms of aging. “One of our questions is, ‘how do you make this battery pack last for five years?’ That involves understanding what causes batteries to age and fail.”
Thelen says that working with Penn State has allowed Norfolk Southern to advance its research and development opportunities. “We don’t have the capabilities or knowledge that a university like Penn State has,” he says. “Chao-Yang is one of the top battery people in the country. Even if we did our own testing, we wouldn’t have his subject knowledge. And Chris Rahn’s expertise helps us incorporate that knowledge into the locomotive.”With the success of this collaborative effort, Thelen hopes to develop a closer relationship between Norfolk Southern and Penn State. “We’re very much interested in having graduates work for us, and this is a good project to give us visibility.”