text: Four people were badly injured when a carriage on the Smiler ride hit an empty one on 2 June.
  Leah Washington, 18, from Barnsley and Vicky Balch, 20, from Lancashire, later each had a leg amputated.
  Ms Washington's boyfriend Joe Pugh, 18, also from Barnsley and Daniel Thorpe, 27, from Buxton, Derbyshire, suffered leg injuries.
  Twelve other people were trapped 25ft (7.6m) off the ground for several hours as emergency services attempted to rescue them.
  "My first words to the [fire] crews were this is probably going to be the most technical rescue they will ever carry out in their careers," Incident Commander Dale Harrison said.
  The Staffordshire Fire and Rescue officer, with 21 years' experience, was in charge on the day of the crash.
  "The first thing was the difficulty in getting access to the ride itself," he said.
  "We had to go down steep steps to get to the accident itself... there were a lot of people already there and we could see that this was not going to be an ordinary rescue."
  He said a helicopter filming the incident as it unfolded and streaming pictures to news channels around the world, coupled with running commentary on social media, made the rescue all-the-more challenging.
  "There was scrutiny of every move we made," he said.
  "I don't think I've been under that level of scrutiny before."
  More than 30 firefighters worked alongside ambulance crews and engineers from Alton Towers. It took four hours to free the last passengers.
  Watch Manager Paul Hewson was on a special platform built to help remove the most seriously injured.
  "The courage of those individuals on that ride in a horrible situation was phenomenal," he said.
  Three hospital trauma team consultants were brought in to help treat passengers at the scene.
  Accident and Emergency consultant Richard Hall said they also helped surgeons and nursing teams at the Royal Stoke to prepare and get the most critically injured into operating theatres as quickly as possible.
  Some of the firefighters involved in the rescue, including Mr Hewson, have since visited the crash victims in hospital.
  Describing them as "inspirational", he said he was able "fill in some of the gaps" for them.
  "They were obviously in a lot of pain [at the time], in an awful situation and were unaware and couldn't see quite a lot of what was happening," he said.
  Mr Hewson said his last images from the scene were "quite distressing" and meeting the victims helped him come to terms with the incident.
  One of the most badly injured Leah Washington tweeted pictures from her 18th birthday celebrations on Tuesday evening.
  Well-wishers on Twitter praised her as "courageous" and inspiring".
  Max speed: 52 mph
  Ride time: 165 seconds
  Highest drop: 30 metres
  Loops: 14
  Cost: Â£18 million
  Opened: 2013
  Some of those injured received interim payouts at the end of last month to help with their rehabilitation.
  Alton Towers' owner Merlin Entertainment said the crash was the "most serious" incident in the park's history and quickly promised compensation to those affected.
  Extra safety protocols have been brought in at all Merlin-owned theme parks.
  On Monday, the firm issued a warning to shareholders, saying the crash was expected to result in a Â£47m drop in profits.
target: The rollercoaster crash at Alton Towers led to the "most challenging" rescue of his career, one firefighter has said.