 Although the short line to Chesham generally had a good safety record , despite its sharp curves and relatively steep gradient , it suffered two significant accidents in this period . On 19 August 1909 the A class engine hauling the 7 @.@ 53 am train from Chesham broke an axle and derailed outside Chesham . There were no injuries but the track was blocked ; a passenger service was maintained by operating shuttle services from each end of the branch to the crash site , where passengers were obliged to walk around the derailed engine to change trains . On 6 November 1909 a backdraught from a locomotive firebox enveloped Robert Prior , the train 's driver , in flames . ( The type of locomotive is not recorded , but it is likely to have been a Metropolitan Railway D Class , which are known to have had a problem with backdraughts . ) The locomotive 's fireman managed to drive the train to Chesham , where Prior died from his injuries two days later . An inquest found that Prior had failed to turn on the blower , and a verdict of accidental death was recorded . 
