I boarded the 18:21 Bletchley to Milton Keynes Central today after ariving from Bedford and it was late arriving at 18:29. I assumed the freight that passed through a minute or two earlier was the reason, however we were held at Bletchley until 18:42 awaiting a change of driver. After we got underway (very slowly) we were informed over the tannoy that ''the driver could not continue after the incident at Tring". Does anyone know what this incident was? Also an 8-car London Midland service sailed past northbound on the fast lines just after we left Bletchley and was in MKC platform 6 at around 18.50. That may be connected as I'm not aware of any northbound LM fasts around that time.