What will replace oil wells-?

The engine/generator/electric motor drive is not as efficient as a mechanical drive system.  It is used on trains because it gives them great tractive force for starting, without having to slip a clutch.  It also allows dynamic braking (where they waste the electricity as heat, instead of storing it).

The currently available hybrid drives are much more efficient than the “train system”, for automobiles.  Yes, they could be even more efficient if they used a small diesel hybrid (or biodiesel) drive.

Fuel cells hold the "promise" of greater efficiency, as they eliminate the IC engine/generator (and associated losses) from the equation. But they are not fully developed yet.

The only way the “train system” will be more efficient, is if we use it for trains and dramatically cut back on our use of cars.  (Gee whiz, public transportation)

An even better system is to electrify the major rail lines and use stationary power plants.  With a 3rd rail or overhead wire system, the energy from dynamic braking can be put back on the system, rather than being wasted (regenerative braking).

In support of my earlier claim that increases in efficiency will drive our energy future, please play the following (recorded) interview-presentation given on December 11 at the Virtual Energy Forum 2008 (December session). (Sorry, there is no direct link, and you may have to register (free) and log in to view, but it's worth it. About 43 minutes.)

"Energy Efficiency in the U.S. Industry"
featuring Doug Kaempf, Program Manager for the US Department of Energy Industrial Technologies Program (ITP)

I found Kaempf's success stories to be very encouraging.

Go to www.virtualenergyforum2008.com. Log in and click the tab "Dec 2008 Sessions" at top; scroll the list of the Thursday, Dec. 11 presentations; it's in the 2:15PM time slot. (FYI, if you're on a Mac, you may have trouble with video display; try "sticky-clicking" any menu in your browser, so the menu stays popped down until you click again. As long as a menu was down, I was able to see video.)

About Kaempf's role:
The ITP leads national efforts to improve industrial energy efficiency and environmental performance. ITP is part of the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy and contributes to its efforts by partnering with U.S. industry in a coordinated program of research and development, validation, and dissemination of energy efficiency technologies and operating practices.