 The [ inspection ] train runs at speeds of up to 125 mph , or 95 mph on this stretch . There would be no point somebody watching it at that speed as they wouldn 't be able to pick up any faults . It has to be run in super @-@ slow motion to spot faults . The train runs for up to 18 hours a day , seven days a week . It would probably take someone most of the month to watch one day 's worth of data . It 's not what it 's there for . It 's a backwards reference tool . 
