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Transport for Wales 769's

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JonathanH

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In the past units that have been under maintenance at Canton have had a run out to Newport for a test run so it might be that, or something different altogether.
Four round trips from Canton / Cardiff to Newport today under STP arrangements - are these the reported 769?

 
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Buzz68

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Four round trips from Canton / Cardiff to Newport today under STP arrangements - are these the reported 769?

769421 test runs after a long period sat in Canton.
 

Bob Price

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Maybe they are bringing that one up to speed to use it as a Thunderbird now the 37 has gone?
 

sd0733

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769421 was at Newport again earlier on test runs to and from Cardiff
 

JonathanH

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Hopefully they will be redeployed when they are replaced on the Rhymney line :D
What is the basis for that hope? All accounts are that TfW are trying to eliminate them from the only route they can run sooner than they originally expected.
 

Bluejays

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Not too likely I'd have thought - there are no drivers qualified on both 769s and the route to Newport, and driver availability is low enough as it is without doing more training.

In the past units that have been under maintenance at Canton have had a run out to Newport for a test run so it might be that, or something different altogether.
That makes more sense !
 

XCTurbostar

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Maybe they could get pantographs re-instated if they are shifted to Cheltenham/Gloucester routes?
 

Techniquest

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Well blow me down, it does actually do something! Maybe, just maybe, it'll be out in service next week when I am potentially in the area...
 

Techniquest

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I would imagine that it gets a fair old thrash along the GWML.

I would imagine so too. Maybe it will actually be usable for more than 5 minutes, it could happen!

If I do end up in South Wales next Wednesday, and I manage to get it in the book, I'll be very surprised but in a good way!
 

Chris125

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What is the basis for that hope? All accounts are that TfW are trying to eliminate them from the only route they can run sooner than they originally expected.

Presumably if reliability is more acceptable by the time that's possible, they'll revert to Plan A? Dare I say the 769s seem to have turned a corner this year.
 

Caaardiff

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I would imagine that it gets a fair old thrash along the GWML.
Which is all well and good, 20 mins, 60 mph non-stop and back.
Climbing the Rhymney line stopping many times on the way is very different.
 

Paul Dancey

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Which is all well and good, 20 mins, 60 mph non-stop and back.
Climbing the Rhymney line stopping many times on the way is very different.

Since their introduction I've noticed the journey up the Penarth branch seems to vary considerably. Some units accelerate nicely and take it in their stride, and even accelerate well when pulling away from Dingle road. Others seem to struggle particularly when pulling away from Dingle road heading up to Penarth. I've often wondered if this is due to difference in individual unit performance, or down to the experience of the driver. Or perhaps it's a bit of both.
 

AM9

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Since their introduction I've noticed the journey up the Penarth branch seems to vary considerably. Some units accelerate nicely and take it in their stride, and even accelerate well when pulling away from Dingle road. Others seem to struggle particularly when pulling away from Dingle road heading up to Penarth. I've often wondered if this is due to difference in individual unit performance, or down to the experience of the driver. Or perhaps it's a bit of both.
Even as 319s, the trains were fairly consistent but it seemed that there were certain drivers that managed to get more performance out of them than others, - especially in poor adhesion conditions. I would imagine that getting used to the limited power under diesel would become another characteristic the some drivers adapt to quicker than others.
 

Dai Corner

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Even as 319s, the trains were fairly consistent but it seemed that there were certain drivers that managed to get more performance out of them than others, - especially in poor adhesion conditions. I would imagine that getting used to the limited power under diesel would become another characteristic the some drivers adapt to quicker than others.
I wouldn't be surprised if drivers who've had a 769 fail on them are a bit more cautious too.
 

Roger B

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There's a report about the TfW 769s in the latest Branch Line News (#1402) from the Branch Line Society. Not sure how much of this is 'new' news, but thought it worth bringing to this thread ....

It states that one driving car from 769426 has been scrapped. I'm assuming that this refers to car 77340, which after doing a bit of a hokey-cokey (in, out, in, out, then shaken all about - ie scrapped), was finally replaced by 77290 from 319001 in January (?) this year. That said I haven't seen a scrapping report for 77340 - does anyone know where (Arlington?), and when? And 769426 still hasn't entered service, remaining sat at Canton. Is 769426 visible passing Canton on trains from Cardiff Central to/from Ninian Park or Ponyclun?

The reports says that pantographs have been removed from all other sets, such that they run solely on diesel, no longer being bi-modes (similar to the Northern Rail story above?). It also refers to an article in May 'Modern Railways' magazine, saying that gentle acceleration from station stops are to prevent traction motor burnout through overheating of winding enamel, though noting that that may not have been the cause of earlier failures in service.

Not an altogether glowing progress report!
 

samuelmorris

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There's a report about the TfW 769s in the latest Branch Line News (#1402) from the Branch Line Society. Not sure how much of this is 'new' news, but thought it worth bringing to this thread ....

It states that one driving car from 769426 has been scrapped. I'm assuming that this refers to car 77340, which after doing a bit of a hokey-cokey (in, out, in, out, then shaken all about - ie scrapped), was finally replaced by 77290 from 319001 in January (?) this year. That said I haven't seen a scrapping report for 77340 - does anyone know where (Arlington?), and when? And 769426 still hasn't entered service, remaining sat at Canton. Is 769426 visible passing Canton on trains from Cardiff Central to/from Ninian Park or Ponyclun?

The reports says that pantographs have been removed from all other sets, such that they run solely on diesel, no longer being bi-modes (similar to the Northern Rail story above?). It also refers to an article in May 'Modern Railways' magazine, saying that gentle acceleration from station stops are to prevent traction motor burnout through overheating of winding enamel, though noting that that may not have been the cause of earlier failures in service.

Not an altogether glowing progress report!
Why wasn't that a problem in the 319 days though?
 

Peter749

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A driver manager at Northern who I asked about why just running on Diesel said the 769s kept tripping the OHLE in Electric mode - even though the 319s don't suffer the problem - if the driver opens the throttle slowly.

You wonder how the 319s have run for so long without any problems
 

DelW

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A driver manager at Northern who I asked about why just running on Diesel said the 769s kept tripping the OHLE in Electric mode - even though the 319s don't suffer the problem - if the driver opens the throttle slowly.

You wonder how the 319s have run for so long without any problems
Maybe because on Thameslink, drivers weren't noted for opening the throttle* slowly!

*(Yes, I do know it isn't actually a throttle on an electric unit)
 

Bikeman78

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Why wasn't that a problem in the 319 days though?
A question that has been asked many times. See also, why don't the 317s flash over despite being mercilessly flogged day after day?

I think the Rhymney 769s get thrashed a lot more now that the drivers are used to them. I must have another go on one.
 

Greybeard33

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It also refers to an article in May 'Modern Railways' magazine, saying that gentle acceleration from station stops are to prevent traction motor burnout through overheating of winding enamel, though noting that that may not have been the cause of earlier failures in service.
Why wasn't that a problem in the 319 days though?
A question that has been asked many times. See also, why don't the 317s flash over despite being mercilessly flogged day after day?
I believe the 319/769 has the same GEC traction motors as the 317, so it might be expected that ageing of the enamel insulation would afflict both classes equally.

However, the traction control electronics are different. The 317 is an AC only unit and has thyristor control, with the thyristors commutated by the AC supply. This was unsuitable for the 319 dual voltage unit, which was the first BR application of an Insulated Gate Bipolar Transistor (IGBT) chopper control. Earlier DC EMUs had electromechanical controls.

This is speculation on my part, but it is theoretically possible that the 319 control allows the motors to be stressed by a higher maximum current on startup than the 317 control, thereby increasing the risk of failure.

Rewinding a burned out motor is a costly repair, and I understand Northern experienced a number of failures before mandating a more cautious driving policy across its 319 fleet.
 
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