A SEPTA bus became stuck on tracks in South Philadelphia on Tuesday, May 5, 2015. Lauren Ferrett/Twitter

A SEPTA bus became stuck on tracks in South Philadelphia on Tuesday, May 5, 2015. Lauren Ferrett/Twitter

SOUTH PHILADELPHIA (WPVI) -- Three people are hospitalized after an accident involving a SEPTA bus in South Philadelphia."It was just something unbelievable," witness Frank Burke said.Burke and other witnesses could not believe what they were seeing.It was around 6:00 p.m. Tuesday when a CSX freight train was blocking crossover traffic on Columbus Boulevard at Tasker as it was hooking up some box cars.Witnesses say the SEPTA route 29 bus was traveling north trying to get around the train and was making a turn at Dickinson."And the bus actually crossed over where you can drive over in front of the tracks and then it pulled a U-turn and headed right into the train tracks and got caught up right in front of the train," witness Lauren Ferrett said.Witnesses say the train was traveling northbound at a slow rate of speed."Came narrowly from hitting the train by about 10 feet or less," Burke said."I thought that maybe they were gonna collide and cause a big explosion," Ferrett said.Burke says thankfully the engineer was able to stop the train."Saw it in time and was able to stop before a major catastrophe," Burke said.The driver and two passengers on board suffered non-life-threatening injuries and were taken to hospitals for treatment.Witnesses are at a loss in trying to understand how the bus driver thought she was going to get over the concrete barriers separating the tracks from the roadway."I thought for a second someone trying to pull a sick move and take a U-turn and then I realize, well, a SEPTA bus shouldn't be doing that," Ferrett said.A SEPTA spokeswoman says the accident is still under investigation.They are talking to witnesses and reviewing video from cameras on board the bus.