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Author Topic: Great Western Main Line electrification - ongoing discussion  (Read 148872 times)
Adelante_CCT
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« Reply #75 on: October 11, 2017, 08:05:27 am »

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Transport - including rail - remains predominantly powered by fossil......
Much like this forum then  Smiley
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trainer
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« Reply #76 on: October 11, 2017, 10:42:34 pm »

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Transport - including rail - remains predominantly powered by fossil......
Much like this forum then  Smiley

How very dare you, sir! I think wind power is more appropriate, especially in my case.  (It's the fibre in the diet that does it.)
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grahame
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« Reply #77 on: October 12, 2017, 06:50:14 am »

(We'll have similar "leads" from Melksham and Bramley.)

And questions asked as to why the leads have been dug across fields not strung up above the line!!

The one on the right is Mk3 but it like its either in a station or a depot

f.y.i. both at stations - Didcot and Motherwell. (I tend not to walk along the track into the countryside to take pics!  Cheesy )
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Electric train
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« Reply #78 on: October 12, 2017, 07:55:02 am »


A good point is made by ET on the elegance of the support arm arrangement. I hope that the ceramic insulators are up to the considerable bending moment imposed on them.

OTC

Yes some types were design for that others designed for compression, its in part why they are so heavy!!!  Angry

AIUI, Stalybridge has to be in, as it is where the new grid connection is, unless someone wants to invest in a very long extension cable ;-)

I think the "extension lead" is needed anyway as the main supply point at the trackside is to be at Ordsall Lane in the centre of Manchester. Otherwise a suicidal pidgeon from Ashton can take out most of Manchester's services. (We'll have similar "leads" from Melksham and Bramley.) The actual GSP is, I believe the switching/transformer compound of the former Heyrod power station. This strongly favours continuing the wires Eastwards to Yorkshire.  It seems that this also supplies most of Manchester's commercial and residential consumers. No pidgeons, please.

The MML situation is also interesting in that the power supply for the Corby wiring is to be taken from a new compound at Braybrooke, Market Harborough, where the 400kV line crosses, suggesting that MH may be the termination. This would also certainly feed to Leicester. The other two MML feeds are proposed for Kegworth (i.e Ratcliffe Power Station site) and Hasland (from Chesterfield NG Substation). I suspect that the key to future electrification may lie in the ease of connection to the juice. The Braybrooke GSP will be the most expensive, hence the one to get installed quick!

As always I sit at ET's feet in these matters.

OTC

There are a number of complicating factors in how a Grid feed is got to the railway. Generally we (the railway) like the 400kV Grid site to be at least 1km from the railway to reduce the risk of imported touch potentials onto the railway during a grid fault.  Grid site can exceed 1700volts where as the railway is 645 volts
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« Reply #79 on: November 01, 2017, 11:11:06 am »

This NR video shows the current state of electrification.  Enjoy the ride......
https://youtu.be/OOAqWW-KXrM
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Red Squirrel
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« Reply #80 on: November 01, 2017, 01:02:45 pm »

Couple of things from this month's Railway Magazine:

1. A letter from a reader who was relieved that, with the cancellation of electrification, Bath will be spared the fate of have OHLE strung across it (Wonder how they'd feel if someone suggested digging up the railway and replacing it with Georgian wildflower meadows?)

2. A report that according to them as know, IETs on diesel power are about 15km/h slower at balancing speed than HSTs. Marvellous.
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grahame
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« Reply #81 on: November 01, 2017, 02:53:33 pm »

2. A report that according to them as know, IETs on diesel power are about 15km/h slower at balancing speed than HSTs. Marvellous.

If the faster high speed sections are electrified how much difference does this make?

Let's take a journey of 305 miles that takes 5 hours and 5 minutes (conveniently, an average of exactly 60 m.p.h.) with an HST, but where the first 173 miles are covered in 120 minutes (86 mph) and the remaining 132 miles take 185 minutes (43 mph).

Electrify the first (fast) 173 miles ... big gains from electrification.  And you will probably never reach balancing speed in those final 132 miles so it really doesn't matter.   

Isn't that the sort of plans they have?
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Bmblbzzz
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« Reply #82 on: November 01, 2017, 03:16:20 pm »

What is "balancing speed" in this context? A cursory search threw up a definition relating to electric traction
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Righto re "balance (or balancing) speed" for any piece of propelled rolling stock powered with electric motors.

Balance speed means the fastest the car or locomotive can move without adding horsepower and/or reconfiguring the traction motor circuits. That's why a unit, a GP9 for example, will not be able to reach full maximum speed if it cannot make transition from series-parallel to parallel circuits.
and variations on that. So basically maximum speed as we'd normally understand it. Presumably same thing for diesel?
https://www.trainorders.com/discussion/read.php?11,1289044
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« Reply #83 on: November 01, 2017, 03:23:09 pm »

What is "balancing speed" in this context? A cursory search threw up a definition relating to electric traction
Quote
Righto re "balance (or balancing) speed" for any piece of propelled rolling stock powered with electric motors.

Balance speed means the fastest the car or locomotive can move without adding horsepower and/or reconfiguring the traction motor circuits. That's why a unit, a GP9 for example, will not be able to reach full maximum speed if it cannot make transition from series-parallel to parallel circuits.
and variations on that. So basically maximum speed as we'd normally understand it. Presumably same thing for diesel?
https://www.trainorders.com/discussion/read.php?11,1289044

My understanding was that it was the steady speed that was attainable up a gradient of a certain slope whilst the unit was producing its maximum continuous tractive effort. Presumably also with ideal railhead conditions.

I could be completely wrong of course  Smiley
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Bmblbzzz
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« Reply #84 on: November 01, 2017, 03:31:28 pm »

That sounds like a sensible definition. But it could be completely wrong!
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« Reply #85 on: November 01, 2017, 04:41:07 pm »

2. A report that according to them as know, IETs on diesel power are about 15km/h slower at balancing speed than HSTs. Marvellous.

If the faster high speed sections are electrified how much difference does this make?

Let's take a journey of 305 miles that takes 5 hours and 5 minutes (conveniently, an average of exactly 60 m.p.h.) with an HST, but where the first 173 miles are covered in 120 minutes (86 mph) and the remaining 132 miles take 185 minutes (43 mph).

Electrify the first (fast) 173 miles ... big gains from electrification.  And you will probably never reach balancing speed in those final 132 miles so it really doesn't matter.   

Isn't that the sort of plans they have?

Nice reasoning.  But the other advantages of electric are better acceleration, regenerative braking and lower air pollution.  It could be argued that the best bits to electrify are the approaches to the stations in order to reduce urban air pollution, get the trains up to speed and away from the stations quickly and allow energy recovery on deceleration to the station.  The gaps in OLE might be best left out in the countryside.   
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Red Squirrel
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« Reply #86 on: November 01, 2017, 04:50:47 pm »

According to The RM (Nov 2017, p7 'Electric good: Diesel bad'):

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Diesel performance from the pair of Class 800 five-car units was below that of an average IC125...

Hitachi personnel confirmed all engines were working and set to full power. Computer modelling... predicts a balancing speed of 118mph on the level in these conditions.

Quote
...spot speeds such as 90mph into Box Tunnel and 83mph coming out were around 10mph shy of an HST. This was worse at the top of the 1-in-100 climb from Dauntsey, where an HST minimum speed would be around 110mph, and the Class 800 units could only manage 91mph.

Anyone remember 'Club 140'?

Edit: Class 800, not 900!
« Last Edit: November 01, 2017, 05:12:42 pm by Red Squirrel » Logged
Bmblbzzz
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« Reply #87 on: November 01, 2017, 05:05:51 pm »

Club 140, speed is free,
Fun and sunshine, there's enough for everyone,
All that's missing is the speed,
But don't worry, you can make up time!
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« Reply #88 on: November 01, 2017, 05:11:24 pm »

Do we know for sure that Chippenham to Temple Meads electrification has been cancelled? As I understand it the work has merely been pushed to the next control period and it is only Cardiff-Swansea which has actually been canned. 
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Western Pathfinder
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« Reply #89 on: November 01, 2017, 05:41:54 pm »

Club 140, speed is free,
Fun and sunshine, there's enough for everyone,
All that's missing is the speed,
But don't worry, you can make up time!


WHAM  BAM you are giving your age away  and mine come too think of it !.
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