Dual-mode locomotives exist in the US as well, essentially entirely in the passenger (commuter) realm. Things like the FL9 (diesel, except 3rd-rail DC in the terminal tunnels of NYC) have been around for over 50 years years. Amtrak and Metro-North-related railroads had similar Genesis (P32-DM) units, now being slowly replaced with dual-mode Siemens Chargers. Some of LIRR's unique diesels are dual-mode for 3rd-rail access to Penn Station. NJ Transit has a fleet of Alstom dual-modes for commuter service partly using the NE Corridor for NYC (Penn) access, with much higher power under wire than on the diesel (high speeds not needed once off the main line). Caltrain is toying with the idea of some battery-overhead hybrids to replace the remaining diesel trains between San Jose and Gilroy - would run on battery south of SJ and recharge from Tamien north under wire.

Main issue with all of them is that they're essentially custom, and therefore expensive, on-off jobs. Without extensive wiring of US railroads, the market for dual-modes of any type is vanishingly small and localized.

Given the cost of building and maintaining catenary, it'll clearly remain something that only high-speed, high-frequency passenger lines can or will do in the US for the foreseeable future. Hence the dabbling with hydrogen in selected situations to eliminate localized and some greenhouse emissions with requiring very large (and heavy) onboard battery systems. The dabbling has yet to reach production stage; still very experimental (and therefore expensive for, again, one-off projects).

Under the present Administration (adding a political angle), I don't think we can expect significant additions to catenary or any other emission-reduction method on ANY US railroad (passenger or otherwise) for at least 4 years, probably more. Passenger railroads are irretrievably 'woke' and it's very likely that some will disappear entirely. So any logical and fact-supported discussion of railroad electrification is interesting but ultimately non-actionable.