Some tense moments on an Amtrak train Wednesday night when two passenger cars separated from the train just 10 minutes outside of the Rensselaer station. Passengers crediting an RPI Freshman, 18 year old Reuben Clarke, with pulling the emergency brake, stopping the cars. Amtrak officials, however, are saying the safety systems in place worked as designed and that is what stopped the cars immediately after separation. While it is not confirmed how fast the train was traveling at the time, trains on that section of track can travel up to 110 miles per hour. No passengers were injured. Amtrak spokesman Jason Abrams says the cause of the separation is under investigation.