Final answer:
Trains today typically operate with new or completely rebuilt wired systems involving overhead lines or a ground-level third rail, important for light rail and high-speed trains.
Step-by-step explanation:
Today, all trains operate with completely rebuilt or new, reliable wired systems. Wired electrified transport employs electricity carried through overhead lines or a 'third rail' on the ground. This method is commonly used in light rail systems and is essential for the operation of high-speed trains.
Wired systems have been a fundamental part of passenger rail service for over a century, and even with challenges such as dwindling profits, efforts like the creation of Amtrak demonstrate a commitment to maintaining and updating this transportation mode.