User blog comment:Stormwell/Thoughts on Technology/@comment-1500935-20140210135550/@comment-3525200-20140213173949

Current runs from negative to positive regardless of wether it's direct or alternating.

Regardless, there are third rail systems out there with the third rail being used to supply power. Though from what we've seen ingame the tracks currently do provide power to the vehicles.

Only other thing that springs to mind is maybe the two different sets of tracks helps with corners?