Assertion: metro's system | /r/MadeOf | elevated lines
Facets:
value: of mostly underground lines
type: OTHER
Source sentences:
text: After this point, a serious debate occurred over whether the new system should consist of elevated lines or of mostly underground lines; this debate involved numerous parties in France, including Victor Hugo, Guy de Maupassant, and the Eiffel Society of Gustave Eiffel, and continued until 1892.