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Great Western Electrification Progress

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Rob F

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But sometimes power is your enemy, unless you are able to apply it very carefully and subtly, just as it is with braking.
This must be the first time that the phrase 'too much power' has been used in relation to class80X on diesel power!

Rob
 
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coppercapped

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I would have thought the greater percentage of powered axles would give them an advantage over HSTs.

I assume they have wheelslip protection systems?
This should really be in another thread, but (mods, please turn a blind eye!) here goes...

The characteristics of an AC drive are very different from the traditional series wound DC motor. If adhesion is lost a DC motor speeds up and separate wheelslip protection systems are required. The so-called SEPEX (SEParately EXcited) DC motors are more slip resistant as the currents through the armature and the field coils are controlled separately and slip can be more easily controlled.

3 phase AC induction motors have no commutator and the armature windings form closed loops, hence the name 'squirrel cage' by which they are sometimes known. A current is induced in the armature's windings by the rotating magnetic field generated in the stator by the three phase supply. The 3 phase motor creates a torque in the output shaft if there is a 'slip' in the order of a few per cent between the armature's speed of rotation and the speed of rotation of the magnetic fields produced by the stator coils. If the armature rotates with the same speed as the stator's magnetic field then the torque falls to zero.

This means that a 3 phase drive is inherently slip resistant - if the axle speeds up because of wheelslip, the torque falls and the wheel should regain grip. The motor cannot turn faster than the frequency applied to the stator coils. To enable the train to operate the power electronics vary the frequency of the supply applied to the stator coils from just above 0 cycles/sec (Hertz or Hz) for starting to whatever is required at the maximum speed of the train. At the same time the applied voltage is also increased.

In variable frequency 3 phase AC drives wheelslip protection is built into the power electronics. External sensors may still be used to monitor the behaviour of the individual axles but the corrections happen through the power control electronics. For example the rate of increase in frequency as the train accelerates may be reduced if an axle is losing adhesion too often or if too many axles are losing adhesion. Or some other combination of divergences from the expected values.
 
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TT-ONR-NRN

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What is getting ridiculous is your habit of not bothering to read other people's posts and then asking over and over about points that have already been answered.

As I have posted several times, the 180s will be replaced from January 2 by five-car Class 800s, the type of IET which will do the bulk of the work on the Cotswold Line in the future. They also will also be replacing Turbo duties over the course of next year as more 800s enter service. Someone else may know at what point nine-car 802s will start to appear in the peaks.

And this thread is about the GW electrification project, not the rolling stock. There are threads about both Class 800s and Class 387s in the rolling stock areas.

Ouch. I'm sorry, but this thread currently has 199 pages and I don't want to read all 5948 comments on it.

Nethertheless thanks for the information.

It should be obvious to you that many posters on here work for the railways and hence have inside knowledge.

If you are rude to them & question their information, they will stop posting it.

If you read the posts, you can easily work out who know and who make stuff up / guess the facts

I was not being rude to the very helpful forum member who was very nice to me. I simply asked if he could tell me where he got this information so I could look myself and not have to bother him for more.

So maybe you should not assume things, and no it was not obvious, thank you.

Some of the information is in the public domain if you care to look. If you look at North Pole depot on RTT in January you will see that 5W12 & 5W14 originate from there and therefore are currently planned to be IET (hst would originate from Old Oak Common). These two ECS trains then do 1W12 & 1W14 along the North Cotswold route. Now plans can be changed, but it is clear that at this stage the intention is for IET to work some of the North Cotswold trains as mentioned upthread.

http://www.realtimetrains.co.uk/sea...0/0200-0159?stp=WVS&show=all&order=wtt&toc=GW

That was a nice response. And thank you, indeed that is helpful.

I do think that many forum members are very judgemental at times, and jump to conclusions about things that don't concern them. Please do not assume far fetched things when there is no need for you to. Don't quote this message either, I don't want to continue this... I will ignore any responses.
 

IanXC

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Can I remind members that this thread is entitled "Great Western Electrification Progress", there are other threads available for rolling stock discussion.
 

Ploughman

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From the Berkshire BBC news page.
http://www.bbc.co.uk/news/av/uk-eng...cow-lane-railway-bridge-in-reading-demolished
Cow Lane railway bridge in Reading demolished
A railway bridge in Reading regularly blamed for causing long traffic queues has been demolished.

The work to remove Cow Lane railway bridge is part of a plan to build a road which can accommodate two-way traffic.

Cow Lane was closed during the weekend as engineers brought the structure down, and reopened at 05:00 GMT on Monday.

The work is due to be completed in August 2018.
 

D1009

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yes... problems at Ladbroke Grove did not affect testing. Multiple Slough-Didcot runs from 0100 to 0930 with IEP and 387.
Does that mean all of platforms 7 to 15 at Reading are now live and usable by AC traction? If so that is a cause for celebration.
 

59CosG95

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Interesting but nothing to do with electrification.
I'd disagree; it may not seem like it has a direct impact on the wiring, but the risk of disruption to the GWEP programme, should the bridge reconstruction be hampered in any way, shape or form, is still high. Any bridge-related farces might be a contributory factor to further wiring delays.
 

TT-ONR-NRN

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Ah, so the long and tedious on board announcement read on every 165/166 train between Didcot and Reading is not so pointless anymore...
 

snowball

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Any update on the postponed Oxford electrification?
No change since it was deferred a year ago. It may get reactivated as a project for the next Control Period (CP6, 2019-24) but this is not guaranteed. The same applies to the two approaches to Bristol TM and the Windsor and Henley branches.
 

LNW-GW Joint

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No change since it was deferred a year ago. It may get reactivated as a project for the next Control Period (CP6, 2019-24) but this is not guaranteed. The same applies to the two approaches to Bristol TM and the Windsor and Henley branches.
Watch for the award of the resignalling contracts for Bristol/Oxford first.
Everything should follow on from that.
Windsor/Henley I suppose could just "happen" when resources free up from the main line, as the signalling is ready I think.
 

coppercapped

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Stop it, I'm in agony tonite after having a wisdom tooth out and your making me dribble all over my keyboard trying to laugh.
Well, if you insisted on tying a thread around it and then slamming the door...

(...my commiserations! As someone said, teeth are a b****r when they are coming, they are a b****r when you've got them and they are a b****r when they're going. Try rinsing with a wee dram... )
 

HarleyDavidson

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I suppose having a shot of alcohol will kill my pain permanently as I'm on codeine, paracetamol & ibuprofen!
 

gwr4090

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No change since it was deferred a year ago. It may get reactivated as a project for the next Control Period (CP6, 2019-24) but this is not guaranteed. The same applies to the two approaches to Bristol TM and the Windsor and Henley branches.

...and Basingstoke which always seemed more likely than the branches ?
 

takno

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Isn't Bristol being resignalled at the moment ?
Since the summer the new Stoke Gifford workstation has covered the bits of Bristol PSB which are getting electrified at the moment. Not sure how firm or imminent plans for the rest of the box, but I suspect the answer is "not very" to both.
 

jimm

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Watch for the award of the resignalling contracts for Bristol/Oxford first.
Everything should follow on from that.

Letting of contracts? For crying out loud, there are new signals already installed all over the place in the Oxford area and from there to Didcot, some already in use, some bagged over awaiting commissioning, new cabling laid, new equipment cabinets installed, etc... all due for completion in a blockade next summer, along with associated track alterations in the station stabling sidings and at Oxford North junction. Control will switch to the signalling centre at Didcot.

Bristol area work is also under way, as noted above - others will presumably know the overall state of progress there.
 

LNW-GW Joint

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Letting of contracts? For crying out loud, there are new signals already installed all over the place in the Oxford area and from there to Didcot, some already in use, some bagged over awaiting commissioning, new cabling laid, new equipment cabinets installed, etc... all due for completion in a blockade next summer, along with associated track alterations in the station stabling sidings and at Oxford North junction. Control will switch to the signalling centre at Didcot.
Bristol area work is also under way, as noted above - others will presumably know the overall state of progress there.

OK, so the Oxford Corridor resignalling project has a CP5 completion milestone of August 2018.
Bristol TM completion is October 2018, and Alstom appears to have the major part of both contracts.
This is a good description of the Bristol project (as of Oct 2016): https://www.railengineer.uk/2016/10/26/bristol-area-signalling-renewals/
Signalling projects have a habit of being deferred or descoped (as both of these have been previously).
Let's hope they come in on track, so to speak, as subsequent wiring is dependent on them.
 

edwin_m

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Both should of course have been completed several years ago if the electrification was to run to the original timescales.
 
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HowardGWR

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^^^ Thanks for the link to the Rail Engineer article. Do I understand it correctly that Bristol's power box blocking the old station beyond platform 1 is to be retained, just to control the line between south of Parsons St and south of Bridgwater, with presumably a full 24 shift working just for that?
The lines being electrified embrace most of the main lines on the Bristol Panel, ending at Temple Meads. There are no proposals to electrify beyond Temple Meads, so there is no technical requirement to immunise the signalling beyond, but it makes sense to extend the new signalling to Parson Street Jn, the junction for the Portbury Dock freight line and soon to be reopened passenger line to Portishead. However, this leaves the route south of Temple Meads, which will remain to be signalled by Bristol Panel for the moment.

Surely they could have done the same for that stretch and saved a lot of staffing costs plus release the entire area by demolition?
 
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