Which major rail system was the first in the world to use an electrified third rail for power, inspired by Tesla's AC power demonstrations?

Long before electric vehicles dominated discussions about sustainable transportation, rail systems were pioneering electric power for mass transit. The early 20th century saw remarkable innovations in rail transport that changed how we move through cities and across countries. Many of these developments were influenced by the electrical innovations of scientists like Nikola Tesla, whose work with alternating current helped power the revolution in transportation. This question explores a fascinating but often overlooked milestone in the electrification of rail transport.

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The London Underground (Metropolitan Line)
The New York City Subway (IRT Line)
The Paris Métro (Line 1)
The Berlin U-Bahn (Kleinprofil network)