Advanced Locomotive Propulsion System
project overview
Project Objective The first step in developing a higher speed, non-electric passenger locomotive is to replace the heavy diesel engine with an advanced gas turbine engine. The higher rotational speed of the turbine makes it The objective of the Advanced much smaller and lighter than the diesel for the same power level. Locomotive Propulsion System (ALPS) project is to operate a While there are significant size and weight advantages to turbines hybrid propulsion system consist- for high-speed locomotives, there are issues with the use of turbine ing of a gas turbine prime mover, powered locomotives. First, a turbine is generally less efficient than energy storage flywheel and high speed alternator in a railroad envi- a diesel and will therefore not provide the same fuel economy. Fuel ronment. The ultimate goal of the economy is further compromised when the turbine is operated at project is to develop a fossil fueled low power during deceleration or constant train speed operation. locomotive capable of sustained Second, maintenance requirements for turbine engines are strongly speeds of 150 mph with acceleration dependent on the number of thermal cycles. comparable to an electric locomotive, improved reliability and efficiency, and Initial simulations of turbine powered locomotives on high speed reduced exhaust emissions. rail corridors indicate that thermal cycling due to variable power demands will require an engine overhaul at least once per year Team Members of operation. Use of the energy storage flywheel compensates for these limitations. During acceleration and grade negotia- tion, turbine power can be supplemented with additional power • The University of Texas at Austin from the flywheel. During regenerative braking, a portion of Center for Electromechanics the kinetic energy of the trainset can be captured by the fly- • AlliedSignal Aerospace wheel and returned to the traction system, improving overall • AlliedSignal Engines system efficiency. The flywheel also enables short term • Argonne National Laboratory load leveling of the gas turbine, reducing the number of • Association of American Railroads thermal cycles. During steady state turbine operation, the • AVCON Advanced Controls Technology flywheel can be accelerated when excess turbine power • Center for Transportation and the is available or decelerated to provide power for Environment (CTE) increased traction system power demands. Figure 1 shows the basic configura- The flywheel is designed to store 480 MJ at 15,000 netic bearing system. Fabrication and tion of the ALPS locomotive propulsion rpm and provides up to 2 MW of supplemental power assembly of the remaining compo- for acceleration and grade negotiation, and enables nents of the propulsion system is in system. recovery of braking energy, improving overall system progress. efficiency. The flywheel will also provide load leveling for the turbine, greatly extending maintenance inter- vals by minimizing thermal cycling. The flywheel rotor Project Description is built of high performance graphite epoxy compos- Next Steps ites and is levitated on non-contacting magnetic bear- The ALPS team is developing several technologies ings. The flywheel incorporates a composite contain- In addition to applications for high for application to propulsion systems for high speed ment liner that contributes to safe operation. A com- speed passenger locomotives, the rail. The 3 MW high speed alternator is an eight pole, pact high performance bi-directional power converter ALPS concept can also be used for three phase synchronous alternator designed to oper- is also being developed to interface the flywheel and commuter and light rail transit appli- ate at 15,000 rpm. Operation at this speed will allow its motor/generator with the locomotive dc bus. Figure cations. The components of the the alternator to be directly driven by a compact 4,000 3 shows a cutaway view of the flywheel and a picture propulsion system can also be used hp TF40 gas turbine, significantly reducing the size and of the assembled flywheel in the laboratory. to provide distributed generation for weight of the prime mover for the locomotive. Figure 2 remote site power as well as is a picture of the high speed generator during labora- improved power quality and UPS tory testing at The University of Texas Center for application for the utility and process Electromechanics facility in Austin, Texas. Project Results industries. The ALPS project has completed fabrication and assembly of the high speed generator and has begun laboratory testing. The energy stor- age flywheel has been partially assembled in preparation for low energy testing of the mag-
Figure1. ALPS power flow schematic
Figure 2. Generator during lab testing. Figure 3. ALPS energy storage flywheel.
Project Lead: University of Texas at Austin Center for Electromechanics
Contact: John Herbst, (512) 232-1645