"The leading train had stopped because it was waiting for another train to leave the Fort Totten station, officials said.
It was unclear why the following train had not received the signal to stop as well, or why the operator did not stop her train manually when she saw the tracks blocked ahead of her, officials said.
Passengers on the second train said it did not slow down at all before impact. "There was no attempt at braking. We just slammed into whatever we slammed into," passenger Theroza Doshi told Reuters."
http://www.reuters.com/article/topNe...55L69G20090623
Not paying attention.
Bad leadership in providing obsolete equipment (the board is appointed by our glorious representatives), and bad operator.