If you had identical circumstances over two days but with different signallers, could one decide to give 9R44 priority and on another day the other signaller gives 1Y45 priority in this example? I know the chances of identical circumstances are extremely remote.
Also, I definitely notice that the EMR Connect likes to dwell longer at Luton Airport Parkway even if its delayed. Today, 1Y43 (1616 EMR Connect from STP) sat at Luton Airport Parkway for 3 minutes according to its arrival and departure time even though it was running 28 minutes late and this made 1Y45 a few minutes late into Luton. I notice 1Y43 made slow progress on departure from STP and assume it was following the Nottingham bound train which also probably was trailing something else. Must have been a very tight squeeze with 9R44 also having to fit somewhere in there.
I did think I imagined the long dwell time at Luton Airport Parkway - maybe it was my heart rate increasing at the prospect of a run for the bus at Luton. Today, seeing a delayed train sit at Luton Airport Parkway kind of confirmed that some trains "like" to sit there .... is it the flawed narrow design of platform 4 meaning everyone walks slowly with luggage on the wrong side of the yellow line and the train can't leave until everyone is clear - possibly when everyone has left the platform? (I hate that station at times).
In the mornings at Luton Station, if the bus is late - I have almost perfected the art of knowing whether its worth walking fast/sprinting for a train. If its on the platform and I'm outside, I know there's no point. If its approaching the platform, it depends where I am at the time. I remember one morning seeing a late running 0625 EMR Connect approaching Luton station - I didn't run for it as I had a Thameslink in mind (0643). I watched the EMR as I walked towards the station entrance and was shocked how quickly it started pulling away after stopping (I'd only just entered the station).