In message , at 06:36:50 on Sat, 1 Jun 2019,
Anna Noyd-Dryver remarked:
Roland Perry wrote:
In message , at 16:14:27 on Fri, 31 May
2019, Certes remarked:
On 31/05/2019 15:38, Roland Perry wrote:
In message , at 15:14:12 on Fri, 31 May
2019, Basil Jet remarked:
On 31/05/2019 14:45, Roland Perry wrote:

Is bustituting an entire line on weekdays just so they can run more
trains on a different one a year before the paths to run both were
available unprecedented?
Not sure what element of that is the core of you question. Doing
engineering works ahead of time, or works on a main line needing an
adjacent branch line to be closed to facilitate it.

They're not closing the branch for engineering work. They're closing it
because they've stolen its weekday paths to strengthen services on the
main line.
If that's the case, I've misconstrued the following reason posted by
GN:
"We are providing rail replacement bus services while
Network
Rail complete a major upgrade to Stevenage station and the track
that connects Stevenage with Watton-at-Stone and destinations
further south on the Hertford Loop. This upgrade involves the
construction of a new fifth platform at Stevenage and the track,
signalling and other infrastructure required to connect it to
Watton-at-Stone.
This major upgrade will mean that Great Northern can run
more
trains per hour between Stevenage and Watton-at-Stone."
Is it possible that closing the branch line connection for the
reasons
they give has *incidentally* released some main line paths which are
useful to LNER ahead of re-timing the whole line for IEP running and KGX
throat upgrade from 2020 (when the branch line reopens for normal
business)?

What that may mean is:
"We have reallocated your platform to more important customers.
You can have your trains back when we build an extra platform
next year."

Which involves closing the branch for engineering work. Chicken, meet
egg.

Does it, though? Presumably if it was closed for engineering works they
wouldn’t reopen it for three trains after midnight and four trains before
0630 every day, and an hourly service at weekends.

The service appears to run single line from a crossover between
Watton-at-stone and Langley Junction, passing under the mainline to the
down side and terminating in the down slow platform at Stevenage, from
where it reverses and runs along the down slow in the up direction to
Langley Jn and back under the mainline, continuing wrong line as far as the
crossover mentioned earlier (which incidentally appears to be where the
Watton-at-stone terminators run to, to reverse.

The new platform at Stevenage will be on the down side, and it appears that
the new line will be adjacent to the down slow from Langley Jn to Stevenage
station. The current working arrangements will otherwise unchanged, I think
(ie running single line from the crossover).

Clearly installing the connection between the branch and the new line will
involve a possession, but not every weekday daytime for 18 months, no
matter how slow you work. It’s only one set of points.

The work must be being done without closing the down slow as that’s in use
throughout.

In other words - yes I have misconstrued GN's spin in their announcement
above.
--
Roland Perry