The Long Island Rail Road has identified the cause of last week's train derailment in Jamaica.According to the LIRR, workers were testing out a new switching system Thursday. Officials say the testing somehow accidentally sent a signal that said it was safe to move a switch.The signal forced a Hempstead-bound train to rear-end a train headed to Huntington. There were no serious injuries, but plenty of travel delays were caused by the derailment.Long Island Rail Road officials say they are encouraged the problem was identified so quickly. However, one commuter says he is upset that testing was performed when the LIRR knew passengers were on trains.

2 LIRR trains bump, causing derailment and delays