Some implementations can include a supplemental regenerative braking system comprising a power take-off section to receive mechanical energy, and an electric clutch to engage the power take-off section and transfer mechanical energy from the power take-off section to an output of the electric clutch. The system can also include a roller stop assembly coupled to the output of the electric clutch and constructed to transfer mechanical energy from the output of the electric clutch, and a generator coupled to the roller stop assembly. The system can further include a flywheel coupled to the generator.