I see that Network Rail are imposing a blockade at Gunnersbury from
Saturday 1st to Sunday 9th April inclusive in order to relay the
junction. Silverlink Metro and LU District Line services from Richmond
to South Acton/Turnham Green will replaced by buses for the whole 9
days.

Why does it take 9 days to replace a double-track junction? Have there
been any recent replacements of similar junctions that have been done
over a weekend, for example?
--
Richard J.
(to e-mail me, swap uk and yon in address)

Richard J. wrote:
Why does it take 9 days to replace a double-track junction? Have there
been any recent replacements of similar junctions that have been done
over a weekend, for example?

The junction is in rather poor shape at the moment - while it is laid
with flatbottom rail, the sleepers are all wood and fishplates abound.
The chord to Acton Lane Junction used by the District is in exceedingly
bad shape (it's all bullhead rail!) and the chord to Bollo Lane
Junction suffers from a down line laid with wooden sleepers.

Drainage in the area of the junction is also rather bad - a short panel
between the trailing points of the junction and the trailing points of
the crossover was removed and relaid because of wet beds. The lack of
space under the overbridge probably also complicates matters.

TheOneKEA wrote:
Richard J. wrote:
Why does it take 9 days to replace a double-track junction? Have
there been any recent replacements of similar junctions that have
been done over a weekend, for example?

The junction is in rather poor shape at the moment - while it is
laid with flatbottom rail, the sleepers are all wood and fishplates
abound. The chord to Acton Lane Junction used by the District is in
exceedingly bad shape (it's all bullhead rail!) and the chord to
Bollo Lane Junction suffers from a down line laid with wooden
sleepers.

I've no doubt the junction itself is in rather poor shape, which is why
it's to be relaid. The plain line stretches to Bollo Lane and Acton
Lane Junction could easily be relaid in weekend possessions.

Drainage in the area of the junction is also rather bad - a short
panel between the trailing points of the junction and the trailing
points of the crossover was removed and relaid because of wet beds.
The lack of space under the overbridge probably also complicates
matters.

Excuses, excuses. There were drainage problems at Victoria at the start
of the District Line relaying works, which necessitated an extra weekend
closure. And the lack of space under the overbridge is not exactly a
rare occurrence (e.g. District Line tunnels). What I'm struggling to
understand is why it's really necessary to suspend the heavily-loaded
peak Richmond line services for a whole week. Or is it just Network
Rail deciding it's more convenient for them to mount a blockade, and sod
the passengers?
--
Richard J.
(to e-mail me, swap uk and yon in address)

Richard J. wrote:
I've no doubt the junction itself is in rather poor shape, which is why
it's to be relaid. The plain line stretches to Bollo Lane and Acton
Lane Junction could easily be relaid in weekend possessions.

Indeed. I'm not suggesting that the reason for the blockade is to
permit this to be done - I'm merely pointing out what the conditions
are at the site.

There were drainage problems at Victoria at the start
of the District Line relaying works, which necessitated an extra weekend
closure. And the lack of space under the overbridge is not exactly a
rare occurrence (e.g. District Line tunnels). What I'm struggling to
understand is why it's really necessary to suspend the heavily-loaded
peak Richmond line services for a whole week. Or is it just Network
Rail deciding it's more convenient for them to mount a blockade, and sod
the passengers?

That may very well be the case. Personally I don't quite understand why
they need nine contiguous days to do it - four I could understand,
seven would be a stretch, but nine?

Richard J. wrote:
I see that Network Rail are imposing a blockade at Gunnersbury from
Saturday 1st to Sunday 9th April inclusive in order to relay the
junction. Silverlink Metro and LU District Line services from
Richmond to South Acton/Turnham Green will replaced by buses for the
whole 9 days.

Why does it take 9 days to replace a double-track junction?

Although the earlier posts in this thread established that there were
some drainage problems, and limited clearance under the road bridge (not
exactly unknown on the District Line), nobody could offer an explanation
of why it will take 9 days.

I'm reposting this, and crossposting to uk.railway, and would
particularly like a response to the following question:

Have there been any recent replacements of similar junctions that have
been done over a weekend, for example?

--
Richard J.
(to e-mail me, swap uk and yon in address)