The southern WCML throws up a number of odd calling patterns on a Sunday evening, which presumably relate to the shutdown to 2 track operation after 20:00, although the exact reasons behind the timetabling of each service and the resultant calling patterns does baffle me somewhat.
2K51 - 20:10 Euston to Milton Keynes calls at all stations up to Cheddington then non-stop to Milton Keynes skipping BOTH leighton Buzzard and Bletchley, despite having 5 mins pathing time between Cheddington and Milton Keynes
Then theres 2 Milton Keynes Terminators that depart Euston within 3 minutes of each other with different stopping patterns:
2K53 - 20:39 Euston to Milton Keynes - calls at Watford, Hemel, Berkhamstead, Tring and Milton Keynes (arr. 21:34)
1K57 - 20:42 Euston to Milton Keynes - calls at Leighton Buzzard, Bletchley and Milton Keynes (arr. 21:30)
What makes this pair even odder is that 1K57 overtakes 2K53 and arrives at MKC first, so i'm not entirely sure where or exactly when the two track section begins, but 1K57 and 2K53 combine at MKC to form empties to Blethchley C.S
2N59 - 21:40 Euston to Northampton - calls at Harrow, Bushey (set down only), Watford then non-stop to Leighton Buzzard, then Milton Keynes, Wolverton and Northampton. Utterly bizzare calling pattern.
It seems 2Y59 at 21:31 to Birmingham New Street makes all the station calls between Watford and Milton Keynes hence 2N59 running fast from Watford to Leighton Buzzard after stopping at the Outer London stations. 2Y59 sits at Northampton for 24 minutes from 22:48 to 23:12 and 2N59 arrives at NMP at 22:55 so it's surprising they don't terminate 2Y59 at NMP and have 2N59 be the through running service to Birmingham as that would reduce the journey time to stations north of Northampton.
Then there are 4 stopping services from Euston to Northampton within 30 mnutes - roughly one every ten minutes, each with a slightly different calling pattern:
2N63 - 22:31 EUS - NMP all stations except Tring and Cheddington
2N65 - 22:42 EUS - NMP all stations except Bushey, Kings Langley, Apsley, Wolverton
2N67 - 22:53 EUS - NMP all stations except Kings Langley, Apsley, Cheddington
2N69 - 23:00 EUS - NMP all stations except Bushey
And on a Saturday evening 2B55 - 19:09 Euston - Bletchley calls at all stations except Apsley creating an hours gap northbound at Apsley, whilst Kings Langley still retains its call, following it is 2K57 at 19:19 to Milton Keynes which is essentially a Tring semi-fast extended to Milton keynes, running non-stop from Cheddington to Milton Keynes.