New York City Subway's signaling system
... that some parts of the New York City Subway's signaling system have not been replaced in 80 years, causing over 11,000 train delays in the span of two months?
... that some parts of the <b id="mwBJE"><a href="./Signaling_of_the_New_York_City_Subway" id="mwBJI" rel="mw:WikiLink" title="Signaling of the New York City Subway">New York City Subway's signaling system</a></b> have not been replaced in 80 years, causing over 11,000 train delays in the span of two months?