England's Alton Towers Theme Park will stay closed on Wednesday as park officials investigate the rollercoaster crash that severely wounded four people and left dozens others stranded for hours.

The accident took place on Tuesday, when one carriage of the Smiler rollercoaster carrying 16 people collided with an empty carriage, leaving passengers stranded 25 feet in the air at a 45 degree angle for more than four hours as they were rescued individually, according to the Telegraph.

Two males aged 27 and 18 and two females aged 19 and 17 were flown to the nearest hospital after suffering severe leg injuries in the crash. Many others required medical attention, including a 20-year-old man who suffered neck and abdominal injuries.

"This has been a terrible incident and a devastating day for everyone here," said Nick Varney, CEO of Merlin Entertainments, responsible for running the amusement park. "I would like to express my sincerest regret and apology to everyone who suffered injury and distress and to their families. The safety of our visitors is our primary concern. The park will remain closed until we understand better the cause of this dreadful incident," He added, reported by BBC.

"All four were given advanced trauma care, pain relief and immobilisation and were each carefully extricated from the ride and on to the platform before being lowered to the ground," a West Midlands ambulance service representative said, The Guardian reported.

"The 27-year-old male was then airlifted to University Hospital Coventry and Warwickshire whilst the others were flown to Royal Stoke University Hospital for further emergency treatment.

"The remaining 12 occupants, six women and six men, suffered less serious injuries. They were released one at a time over a time period of four hours and lowered to the ground in order for a further assessment of their condition.

"One of the 12, a male in his 20s, was treated for neck and abdominal injury and was taken to the Royal Stoke University Hospital by land ambulance for further assessment and treatment."

The crash is the most serious incident to take place at Alton Towers since its opening 35 years ago. The Staffordshire resort is one of England's leading tourist attractions, attracting up to 3 million visitors every year.