ANTHONY ESPOSITO and NOE TORRESA AT least 23 people were killed and 65 were hospitalized when a railway overpass and train collapsed onto a busy road in Mexico City on Monday night, crushing cars under fallen carriages and rubble. The authorities halted rescue efforts shortly after they began, saying there was a risk that more train parts and debris could slam down onto the road. A video on local channel Milenio TV showed the structure plummeting onto a stream of cars near the Olivos station in the southeast of the city at around 10.30 p.m. local time, sending up clouds…