That might explain the cancellations but it surely does not explain the delays, the wheel cleaning, the level crossing issues nor the disappearing trains?
Because of the 'issues' with the 755s, Network Rail have bought in a special working, (3.5. working) which is, in a nutshell Absolute Block working, which extends the section a bit, using controlled signals, then if a 755 vanishes for any length of time, or even fleetingly, if there is an Auto signal mid section it would clear to a green, 3.5 addresses this, but makes the section longer, it also increases the Signaller workload somewhat, add to this staff taking 'blocks' to examine the 755's after each trip, and associated paperwork, you can see how the job slows down ! Also this method of working is used for ALL trains, regardless of type, this is the safest way, rather than this train, but not that train, a mistake could easily be made !