Abstract: The acoustic black hole (ABH) effect, which decelerates the propagation of elastic waves and suppresses boundary reflections, presents a novel mechanism for vibration energy harvesting. A dual-ABH piezoelectric beam energy harvester has been designed for application in railway track systems. A semi-analytical electromechanical coupling model was developed using the energy functional variational principle and Gaussian expansion method. Validation was conducted through finite element simulations. Under train-induced loading, energy harvesting behavior was investigated with respect to ABH geometric parameters and terminal mass. Four principal energy harvesting bands were identified within the 0~1500 Hz range, yielding a peak output voltage of 4.83 V and a maximum efficiency of 2.23%. Optimal energy conversion was achieved when the piezoelectric patch length equaled half the bending wave wavelength of the host structure. Efficiency was further improved by strengthening the ABH effect or through appropriate tuning of the terminal mass.