 The A4's regulator was then opened to full cut-off, resulting in the engine breaking free from the generator van and rushing off up the track.Probably the standard screw coupling was then used instead of the 'buckeye' couplings on the two vehicles, which would have required an inspection due to the various attempts to break them apart.In June 2000, a member of the Royalty Protection Branch (SO14) accidentally discharged his 9mm Glock automatic pistol while the train was halted for an overnight stop in South Wales.