Alternative plans for Ely upgrade work

[Magdalia]

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Crayon time! I know we've been here before, but here's a route using the same curves as the existing one through Queen Adelaide, just shifted to start just after Kiln Lane crossing.

We'd lose the west curve, but the new route crosses Queen Adelaide at roughly the same point as the west curve bridge, eliminating the crossing. It only skims the Roswell Pits area, staying out of the deep water. People will moan about bats etc, but the impact is very small.

I've also superimposed the new developments, since they don't show on Google maps yet.

As a bonus, there's a 500m straight north of Prickwillow road for a potential Ely North station for when Cams Metro give up with the autonomous bus nonsense

Possibly expensive, but would it be as much as all the road bypasses in the official proposals?

Your new red crayon line goes straight through the Roswell Pit Site of Special Scientific Interest. Yes, people will moan about the bats etc. If you had used a map, instead of an aerial photo, you would also see that you have gone through the middle of the lake on the inside of the Ely West Curve. Basically you are proposing a line through the middle of a marsh.

And the Cambridge Autonomous Metro has been dead since Palmer was kicked out as mayor more than a year ago.

Nice. The bridge would no doubt have to be rebuilt in situ to suit the new angle of intersection, but at least existing ramps might be reused. You could have a new double junction on the straight stretch with the Kings Lynn line diverging across open fields towards the current alignment (See my yellow addition). That would leave only the Norwich line level crossing.
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The northern part of the yellow crayon line, north of the existing Peterborough line, is similar to what I proposed here, but I don't have any crayons. My proposal requires far less new track, and does minimal environmental damage, but it does require a road bridge over what is now the Peterborough line at Queen Adelaide.

I'm responding to this here as it is essentially speculative.

Yes, trying to work out what to do in the Fens just by looking at a map is not advisable. In particular you have to get the Norwich line over the river.

But it did set me thinking, and I would do the polar opposite. At Ely North Junction/Queen Adelaide I would keep the Norwich line and the Peterborough line, but junk the Kings Lynn line. Furthermore, I would make no changes for the Norwich line at all. The Norwich line does not need more track capacity, any capacity issues can be addressed by running longer trains. If capacity on the Norwich line is unchanged then the easternmost level crossing can be left as it is and nothing needs to be done for Prickwillow Road, Queen Adelaide Way and Branch Bank.

I would take the Lynn line off the Peterborough line just north of Queen Adelaide on a new alignment to rejoin the existing alignment a bit further north. This would require crossing a few drains and the farm track that currently runs next to the line on the west side. It is about the same amount of new track as the Hitchin flyover, though double not single.

This also gives the opportunity for grade separation of the Peterborough and Kings Lynn lines. The line from March clips the north end of the Isle of Ely, passing through a cutting east of Chettisham and is then on a falling 1/230 gradient to Queen Adelaide. This is ideal for taking the up Peterborough line over the top of the new Kings Lynn alignment. The old alignment of the up line would need to be retained as far as Ely West Junction to give access to the Ely West loop.

Any bridges for the new alignment and grade separation ought to be no more of an engineering challenge than the Ely southern bypass.

Road wise all that is required is a bridge over the combined Peterborough/Kings Lynn line at Queen Adelaide, and possibly something at Kiln Lane. I have to confess that I don't know what to do about Kiln Lane!

 

[Maltazer]

Road wise all that is required is a bridge over the combined Peterborough/Kings Lynn line at Queen Adelaide

And herein lies the problem, and the reason for all the suggested re-routing of rail lines, bypasses etc.

You can't build a bridge there because it's surrounded by houses.