Here's a Wabtec video [0] about their battery-electric locomotive. They are not limited to yard service; they're also marketing them as "hybrid consist" pullers

Here's a Wabtec video [0] about their battery-electric locomotive. They are not limited to yard service; they're also marketing them as "hybrid consist" pullers, which means that if you team them with a standard diesel-electric locomotive they reduce the diesel fuel needed to pull the train and they capture some of the train's braking energy to recharge the batteries. Left unstated is whether the diesel-electric locomotive in the consist could recharge the batteries of the battery-electric locomotive as the train is rolling. I expect it could but it's probably pointless because it's more efficient to let the diesel-electric pull the train. [0] https://www.youtube.com/watch?v=zIgmNOxa5aI https://www.youtube.com/watch?v=zIgmNOxa5aI