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Author Topic: Great Western Main Line electrification - ongoing discussion  (Read 103331 times)
onthecushions
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« Reply #855 on: September 03, 2019, 09:31:06 am »

But if you look at this pic from Durham you can see that it's certainly possible to have something very visually unobtrusive without resorting to extreme measures.

As long as you don’t mind it all getting blown down when the wind picks up...  Wink

But these are portals not headspans, surely, so not even the big bad wolf could blow them down.

Conservation usually promotes good, neat, well proportioned modern design, as here.

IMHO the Steventon bridge problem has nothing to do with historic conservation other than  mis-using the legislation.

OTC
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onthecushions
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« Reply #856 on: September 07, 2019, 09:31:19 am »


On another website it is reported that the speed limit through Steventon will be raised to 110mph from 0930 Sunday 15 September (including the 387's).

I imagine that when the bridge has finally to be rebuilt it may be at the expense of the triumphant Council Tax payers of the District, not NR.

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ellendune
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« Reply #857 on: September 07, 2019, 10:58:33 am »


On another website it is reported that the speed limit through Steventon will be raised to 110mph from 0930 Sunday 15 September (including the 387's).

I imagine that when the bridge has finally to be rebuilt it may be at the expense of the triumphant Council Tax payers of the District, not NR.

OTC

No it is railway bridge and unless it is rebuilt as part of a road improvement scheme it will remain down to NR. Even then, the highway authority would probably require a contribution from NR for betterment. 
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Electric train
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« Reply #858 on: September 11, 2019, 06:58:25 am »

The Bath problem (and a few other similar places).  Now, after the end of October, when we can choose to no longer comply with TSIs (well, isn't that what B****T is supposed to be about) how about this: Yesterday I was travelling under/looking at the tramway style of 25kV electrification leading into the Depot at Soho in Birmingham.  It appears to use a single wire (so not actually catenary) and simple MK1 structures (quite slim and unobtrusive).  If view of the low speeds and the fact most trains stop at Bath, why not use it there?  Now where is ET when you need him Wink

The "trolley wire" systems used in depots are designed for a max lines speed of 15 or so mph and relatively low traffic and power densities.

I believe on of the issues at Bath is to do with the position of the Pan on the class 80X trains over the passenger door.  There is also the unresolved aesthetics objections through Bath, all of which made it easy for DfT to pull the plug.

It has been stated by the DfT, ORR and RSSB that the UK will continue to comply with TSI's post B-----t certainly for the foreseeable future they are part of the "great repeal Bill"
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Mark Carne 26 June 2015 - "The challenges of delivering myriad improvement projects while still running a railway seven days a week were simply overwhelming".
Noggin
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« Reply #859 on: September 12, 2019, 11:19:01 am »

The Bath problem (and a few other similar places).  Now, after the end of October, when we can choose to no longer comply with TSIs (well, isn't that what B****T is supposed to be about) how about this: Yesterday I was travelling under/looking at the tramway style of 25kV electrification leading into the Depot at Soho in Birmingham.  It appears to use a single wire (so not actually catenary) and simple MK1 structures (quite slim and unobtrusive).  If view of the low speeds and the fact most trains stop at Bath, why not use it there?  Now where is ET when you need him Wink

The "trolley wire" systems used in depots are designed for a max lines speed of 15 or so mph and relatively low traffic and power densities.

I believe on of the issues at Bath is to do with the position of the Pan on the class 80X trains over the passenger door.  There is also the unresolved aesthetics objections through Bath, all of which made it easy for DfT to pull the plug.

It has been stated by the DfT, ORR and RSSB that the UK will continue to comply with TSI's post B-----t certainly for the foreseeable future they are part of the "great repeal Bill"

Could you explain why the position of the pan would be a problem in Bath and is not, say a problem in Didcot or another station with similar canopies?
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ray951
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« Reply #860 on: September 15, 2019, 07:12:13 pm »

Good to see IET trains running through Didcot with pantographs up today. I believe it is 3 years since the first electric trains ran to Didcot, so better late than never.
Now let's finish the electrification to Oxford.
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paul7755
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« Reply #861 on: September 15, 2019, 08:33:35 pm »

Could you explain why the position of the pan would be a problem in Bath and is not, say a problem in Didcot or another station with similar canopies?
Wasn’t the problem electrical clearance between pantograph horns and listed canopies, so they solved it by building the platforms out a couple of years ago?

Paul
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ray951
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« Reply #862 on: September 15, 2019, 08:45:57 pm »

Problem was a road bridge at Steventon a few miles west of Didcot, as mentioned earlier NR have found a way to run IET trains at 110mph on electric through the bridge, this started today.
Before today most IETs going through Didcot were on diesel power, now all IETs except those going to/from Oxford can be on electric power.
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Bmblbzzz
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« Reply #863 on: September 16, 2019, 09:16:50 am »

Could you explain why the position of the pan would be a problem in Bath and is not, say a problem in Didcot or another station with similar canopies?
Wasn’t the problem electrical clearance between pantograph horns and listed canopies, so they solved it by building the platforms out a couple of years ago?

Paul
It was caused or partly caused by the curvature of the platforms IIRC.
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Day return to Infinity, please.
Western Pathfinder
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« Reply #864 on: September 16, 2019, 09:31:04 am »

I'm hearing that the knitting has gone live from Patchway through Pilning and the Severn Tunnel,,not in service as of yet but undergoing testing .
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onthecushions
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« Reply #865 on: September 16, 2019, 10:46:11 am »

I'm hearing that the knitting has gone live from Patchway through Pilning and the Severn Tunnel,,not in service as of yet but undergoing testing .

...all the way to St Bride's ATFS at 162m01c if railuk forum tells us true.

OTC
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REVUpminster
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« Reply #866 on: September 18, 2019, 10:55:06 am »

Experts needed:

Down here in the South West there is talk in the long run of wiring between Newton Abbot-Plymouth to assist going over the Devon banks and generally speed up the service.

Now this is what I want to know; the wheels of the train are driven by electric motors and when no wires diesel engines provide the electricity. So when using diesel engines is there less power available or some other reason or have I got it wrong completely?
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Western Pathfinder
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« Reply #867 on: September 18, 2019, 04:51:00 pm »

No you're not wrong, the engines when running provide an amount of power to the generators this is used to drive the wheels as well as all the on board lights air con etc etc.
When running on the Mains every thing is powered up as before ,only there is more juice available,so speeds can be increased. That is the simple way of looking at ,hopefully of some help.
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onthecushions
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« Reply #868 on: September 18, 2019, 10:17:52 pm »


Because rolling stock is now built by private contractors rather than BR, the technical details, being commercially sensitive, can be harder to come by.

However, in principle the motor coach of an IEP has a diesel engine of either 560kW or 700kW output. I believe that this is shaft power not alternator output. By the time this has gone through the generation, inverter control, traction motor and hotel power systems, at least 20% will be lost, giving power at rail of no more than 450/560kW. When using the 25kV overhead supply, the four traction motors, each of 226kW continuous maximum rating (CMR) can deliver 904kW at rail, nearly double. Short term ratings for traction motors can also be 50% higher, if used.

Diesels can perform reasonably on flat terrain, with few stops, where speed potential is low and traffic is light.

This demonstrates the partial fallacy in DfT statements that diesel bi-modes can deliver the same for the passenger as full electric traction. Electric trains have a capital cost of just over half of diesel trains (Roger Ford) and have energy and maintenance costs equally lower. Their higher reliability means fewer are needed. Certainly more of our GWR (let alone the MML etc) justifies wiring, if only NR could get its corporate head round it.

Others may know better

OTC

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Electric train
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« Reply #869 on: September 22, 2019, 04:17:19 pm »

Experts needed:

Down here in the South West there is talk in the long run of wiring between Newton Abbot-Plymouth to assist going over the Devon banks and generally speed up the service.

Now this is what I want to know; the wheels of the train are driven by electric motors and when no wires diesel engines provide the electricity. So when using diesel engines is there less power available or some other reason or have I got it wrong completely?

For Diesel to provide the same power as 25kV electric traction they would need to be large of large number of them.  300 Amps from the OLE is 7.5MW that means you would need 10 750kW alternators on the train which means each engine would need to be over 1MW output.

300 Amps is not an usual peak starting current for intercity type trains
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Mark Carne 26 June 2015 - "The challenges of delivering myriad improvement projects while still running a railway seven days a week were simply overwhelming".
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