Service recovery (or lack of) on GTR Great Northern

[sharpener]

Looks like it was helped a bit by the signaller holding onto sending 2H57 Cambridge North to Liverpool Street and instead giving 1T50 priority - usually 2H57 seems to get priority as soon as 1T50 is more than a minute or so late, which makes 1T50 lose another 3-4 minutes.

Timetable could hardly have been worse from the POV of one or other getting delayed. At least common sense prevailed on that occasion and the resulting delay to 2H57 was trivial.

 

[MikeWM]

Timetable could hardly have been worse from the POV of one or other getting delayed. At least common sense prevailed on that occasion and the resulting delay to 2H57 was trivial.

Yes - which in my experience is very rare, the signaller usually sends 2H57 out if there is any chance 1T50 will delay it. Which causes an even longer delay to 1T50 than before the stop boards at CMB were moved halfway to Waterbeach, as 2H57 now takes considerably longer to get clear of the platform at CMB.

I'm not sure why 2H57 departs off-pattern at 1842 rater than 1843 anyway (and then gets to sit at Audley End for 3 minutes). I'm guessing it is due to the off-pattern Thameslink 1852 off Cambridge to Brighton, but for why *that* is off-pattern (ie. at 1852 rather than 1853) I don't see any obvious explanation.

 

[Class 170101]

Yes - which in my experience is very rare, the signaller usually sends 2H57 out if there is any chance 1T50 will delay it. Which causes an even longer delay to 1T50 than before the stop boards at CMB were moved halfway to Waterbeach, as 2H57 now takes considerably longer to get clear of the platform at CMB.

I'm not sure why 2H57 departs off-pattern at 1842 rater than 1843 anyway (and then gets to sit at Audley End for 3 minutes). I'm guessing it is due to the off-pattern Thameslink 1852 off Cambridge to Brighton, but for why *that* is off-pattern (ie. at 1852 rather than 1853) I don't see any obvious explanation.

Parallel move at Shepreth Branch Jn between 1N67 and 2H57 towards West Anglia 18:51 to 18:53 and then between 9S57 and 2C59 heading towards Hitchin and 1T52 heading from Hitchin across Shepreth Branch Jn between 18:56 and 19:00

 

[sharpener]

Parallel move at Shepreth Branch Jn between 1N67 and 2H57 towards West Anglia 18:51 to 18:53 and then between 9S57 and 2C59 heading towards Hitchin and 1T52 heading from Hitchin across Shepreth Branch Jn between 18:56 and 19:00

Not sure why this is an issue. Up West Anglia and Down GN trains are not the problem, it's the other two paths through the jn that cause the conflicts.

 

[43074]

Parallel move at Shepreth Branch Jn between 1N67 and 2H57 towards West Anglia 18:51 to 18:53 and then between 9S57 and 2C59 heading towards Hitchin and 1T52 heading from Hitchin across Shepreth Branch Jn between 18:56 and 19:00

That doesn't explain why 9S57 is off pattern at all as it could still run 1 minute later from Cambridge and not break the junction working at Shepreth, it would just go over at 18/57 30s after 1T52 comes up from Royston and 3 mins ahead of 2C59.

 

[choochoochoo]

Going off slightly off topic, why did they make Shepreth Branch junction speed 30mph in the down royston direction but 50mph in the up royston direction when they redesigned the junction ? Why was 50mph not done in both directions.

 

[jammmmmsssssss]

Going off slightly off topic, why did they make Shepreth Branch junction speed 30mph in the down royston direction but 50mph in the up royston direction when they redesigned the junction ? Why was 50mph not done in both directions.

I think it will be after the commissioning of Cambridge resignalling phase 2 at Christmas

 

[Class 170101]

Not sure why this is an issue. Up West Anglia and Down GN trains are not the problem, it's the other two paths through the jn that cause the conflicts.

That doesn't explain why 9S57 is off pattern at all as it could still run 1 minute later from Cambridge and not break the junction working at Shepreth, it would just go over at 18/57 30s after 1T52 comes up from Royston and 3 mins ahead of 2C59.

1N67 uses Platform 8 at Cambridge thats needs a four minute junction margin at Cambridge with 9S57 (platform 1) 18:52 to 18:56

 

[sharpener]

1N67 uses Platform 8 at Cambridge thats needs a four minute junction margin at Cambridge with 9S57 (platform 1) 18:52 to 18:56

Seems an awkward set of moves.

I thought Birmingham trains normally use P4 and Brighton trains P7/8, which is a much better arrangement not involving both trains crossing each other and over virtually the whole layout at CBG, and in the case of 1N67 having to cross back again as well.

But a busy time of day and even now none too many platforms. Not helped by 2H46 spending 12 mins occupying P7 before going off to the sidings, ?driver change or something?

 

[Class 170101]

Seems an awkward set of moves.

I thought Birmingham trains normally use P4 and Brighton trains P7/8, which is a much better arrangement not involving both trains crossing each other and over virtually the whole layout at CBG, and in the case of 1N67 having to cross back again as well.

1N67 cannot use Platform 4 due to 2K89 arriving in Platform 5 the overlap on Platform 4 extends over the points at the Country End of Cambridge. Insufficient gap behind 1N67 with 1T52 behind it (arrive 19:01 to split) regardless of 1T52 using Platforms 1 or 4. If 1N67 went 18:58 might work but it would be off pattern from Cambridge, so it uses Platform 8.

But a busy time of day and even now none too many platforms. Not helped by 2H46 spending 12 mins occupying P7 before going off to the sidings, ?driver change or something?

2H46 has to wait for 5T50 (split from 1T50) to enter sidings at Cambridge Sidings North. It may be able to go at 18:45 depending on how many minutes are needed between each arrival. 5T50 is 18:50 arrival at Cambridge Sidings North so maybe best to wait 12 minutes for clear run to sidings and to check train is empty before sending it to sidings.

 

[sharpener]

1N67 cannot use Platform 4 due to 2K89 arriving in Platform 5 the overlap on Platform 4 extends over the points at the Country End of Cambridge.

Didn't realise, that would seem to be a significant operational limitation!