BNSF have used the multi engined concept, coupled with large battery packs, for quite a few years in switching service. They used to call them Green Goats and I believe 3 Cat diesels that can be swtched on/off as needed. The concept works. Lots of stuff on the net.
Warbonnet, my relative who works on Network Fail assures me thats the term! Mind you I could put up with the .....ing for the dosh they get paid, much much better than when I worked on BR