The ride has had issues before, it was opened in May

Nov 4, 2013 15:47 GMT  ·  By

A roller coaster ride has been shut down and closed off after having a few wheels become loose and fall off.

The Smiler, at Alton Towers in the UK, cost about £18 million ($28 million / €21 million) to open in May. It has already had a piece of track fall off in July.

The Independent writes that, this time, it has lost a few “small, plastic guide wheels.”

“Several were flicked into the guests sitting in the front row of the train,” an amusement park spokeswoman describes.

The ride has 14 loops and one of them offers guests a 30m (98ft) drop. Additional pieces of debris were caught in the safety netting.

Four guests in the front row suffered minor injuries and they were attended by park medical staff. None of them required additional medical check-ups. They only reported bruising, but they have escaped the incident fairly unscathed.