Similarly, I sit next to a season ticket holder at Leicester Tigers who works for Caterpillar. Subject to the usual commercial sensitivities, he doesn’t go into specific details, but they’re working on hydrogen and electric power units with partners, the latter being hot swappable battery packs. The hydrogen options were existing diesel engines modified to run on hydrogen as welll, but NOx was still a problem.
Electric motors, weight and torque are good partners for bulldozers etc.