GWR Class 769 information. (Units no longer with GWR - Off Lease March 23)

[rebmcr]

If not already posted there is a good video, with sound, of the test runs on 16 & 18 June on youtube. the title is

GWR Class 769 Flex Test Runs on the North Downs and Brighton Main Lines - 16 & 18/06/21​

The poster has requested that links are not shared without permission the above is the best I can do

That's not what they have requested. Their video description states:

DO NOT RE-UPLOADED/USE MY VIDEOS WITHOUT VALID PERMISSION, THEY ARE OWNED BY ''CHOO-CHOO!!Plane''

Linking is not reuploading, it in fact helps the original creator to remain the sole source of their work, which is what they are trying to preserve.

 

[30909]

That's not what they have requested. Their video description states:

Linking is not reuploading, it in fact helps the original creator to remain the sole source of their work, which is what they are trying to preserve.

Apologies I'm a novice at social media and other sources and felt it best to err on the side of caution.

 

[Mike Buckner]

Thanks everyone for the info re air cooling/conditioning

 

[gallafent]

That was my understanding -

Isn't that just forced air ventilation? I thought air cooling still required refrigeration?

Air cooling absolutely does require refrigeration. Without that it's just “ventilation”!

Air cooling, on one hand, just reduces the temperature of the air (with most likely some collateral change in its relative humidity of course). Air conditioning, on the other, also controls moisture content (and thus interior relative humidity), and sometimes other factors (by filtering in various ways to remove dust or other pollutants, mixing recycled interior air with fresh air from outside the space being conditioned to maintain correct oxygen and carbon dioxide levels, reduce ozone concentrations, …).

Air conditioning

Air conditioning - Designing Buildings - Share your construction industry knowledge. Use of the term ‘air conditioning’ (AC) can be confusing.

www.designingbuildings.co.uk

Use of the term ‘air conditioning’ (AC) can be confusing.

In some of the strictest definitions, air conditioning is used to describe systems that control the moisture content of air, that is, its humidity. This can include humidification and dehumidification. Humidity control can be important for; the comfort of building occupants, to reduce the incidence of condensation (both surface and interstitial), for specialist environments such as swimming pools, and where the protection of sensitive items requires particular conditions.

However, dehumidification of air is generally achieved by cooling. As the temperature of air falls, it is less able to 'hold' moisture, that is, saturation water vapour density falls, and so relative humidity rises. When relative humidity reaches 100%, the air will be saturated. This is described as the 'dew point'. If the air continues to cool, moisture will begin to condense, dehumidifying the air.

This means that humidity control and cooling are often considered together as ‘air conditioning’. Cooling and dehumidification are important contributors to thermal comfort. This is because the ability to perspire, and so to lose heat by evaporation from the skin, is limited by the humidity of the air.

As a result, remaining cool is dependent on both temperature and humidity (as well as a number of other factors, see Thermal comfort for more information). A combination of reduced air temperature, and reduced humidity helps people to remain cool.

The cooling of air alone, often described as ‘air conditioning’ is more correctly referred to as ‘comfort cooling’. However, because it cools the air, comfort cooling may include some incidental dehumidification.

This “comfort cooling” is what I understand has been added to class 165s (first Chiltern's, now also GWRs, though unfortunately they didn't bother to replace the hopper windows, just locking them closed, … I perceive the GWR versions being noticeably noisier inside, though I haven't measured).

As one example of when air conditioning is noticeably a big step up in comfort from just air cooling: when it's cold outside, interior humidity can be uncomfortably low. An air conditioning system might increase the humidity of the air by adding some water vapour, after the air has been heated, to make the environment more comfortable. An air cooling system can't do that, it can only cool air

As a footnote, I imagine that in cold weather the trains fitted with “air cooling” rely on more conventional (electric filament, or waste engine heat, via water pipes) heating to warm the cabin, whereas a train with “air conditioning” can run the heat pumps backwards ( ) to circulate warm air as part of the HVAC approach to maintaining a comfortable cabin environment.

 

[rebmcr]

Apologies I'm a novice at social media and other sources and felt it best to err on the side of caution.

No worries, I am always happy to share knowledge.

 

[Deepgreen]

I have just heard a 769 on a test run moving away from a signal stop opposite my garden (about 400 metres away) at Betchworth, and it was eerie how loud the electric motors were and how silent the diesel was. It was as if the line was electrified!

 

[AM9]

I have just heard a 769 on a test run moving away from a signal stop opposite my garden (about 400 metres away) at Betchworth, and it was eerie how loud the electric motors were and how silent the diesel was. It was as if the line was electrified!

That's presumably because the motors and their pinion drives are probably worn and noisy, yet the engines are new and well silenced. All the EE507-like series wound DC motors have a certain sound.

 

[Tw99]

That's presumably because the motors and their pinion drives are probably worn and noisey, yet the engines are new and well silenced. All the EE507-like series wound DC motors have a certain sound.

From the video, the DC motor noise is exactly like an old SR slam door unit. Quite nostalgic...

 

[AM9]

From the video, the DC motor noise is exactly like an old SR slam door unit. Quite nostalgic...

... as in EMUs that were all equipped with EE 507 series wound DC motors. That sound was also found on 302s, 303s, 304s, 305s, 308s, 311s, 317s, 318s, 320s, 321s, 322s and 325s, all ac EMUs.

 

[Class319&373]

Will this be its first test down on the SWML tomorrow, or is this just a random loco move?

Realtime Trains - 590R 1152 Reading Traincare Depot to Eastleigh Arlington (Zg)

Realtime Trains is an independent source of live realtime running information for the Great British railway network.

www.realtimetrains.co.uk

 

[father_jack]

Will this be its first test down on the SWML tomorrow, or is this just a random loco move?

Realtime Trains - 590R 1152 Reading Traincare Depot to Eastleigh Arlington (Zg)

Realtime Trains is an independent source of live realtime running information for the Great British railway network.

www.realtimetrains.co.uk

Haven't GWR been hiring in ROG 57s for the sleeper ?

 

[spark001uk]

This has a Colas TSC, so not a ROG move.
The working doesn't look like it's returning, so could be the damaged unit going for repair.

 

[MarlowDonkey]

It could be a struggle for the 769s to sit at Reading on AC when they will be mainly berthed on platforms 4-6, which are DC.

Are they not electrified for the shuttle to Newbury?

 

[43096]

Are they not electrified for the shuttle to Newbury?

Wrong end of the station! Platforms 1-3 are the "Newbury" platforms. 4-6 are the "Southern" platforms that are DC electrified.

 

[JonathanH]

Are they not electrified for the shuttle to Newbury?

Platforms 1-3 are.

Basingstoke services could run on AC between Reading West and Reading.

 

[FGW_DID]

Will this be its first test down on the SWML tomorrow, or is this just a random loco move?

Realtime Trains - 590R 1152 Reading Traincare Depot to Eastleigh Arlington (Zg)

Realtime Trains is an independent source of live realtime running information for the Great British railway network.

www.realtimetrains.co.uk

This has a Colas TSC, so not a ROG move.
The working doesn't look like it's returning, so could be the damaged unit going for repair.

769943 heading off to Arlington for storage. (Nothing more than to free up space at Reading.)
769946 will be the unit out on the FFR run over the NDL to Gatwick.

 

[Class319&373]

769943 heading off to Arlington for storage. (Nothing more than to free up space at Reading.)
769946 will be the unit out on the FFR run over the NDL to Gatwick.

Ah ok, thanks for the info.

 

[MarlowDonkey]

It could be a struggle for the 769s to sit at Reading on AC when they will be mainly berthed on platforms 4-6, which are DC.

If they run to Basingstoke or Newbury, they will be at the AC end.

If running empty to or from Twyford, Maidenhead and Slough to form the branch line shuttles, would that be AC as well?

 

[adc82140]

Are they planned to go to Henley? The bay at Twyford isn't wired, so they would be in diesel all day.

 

[cactustwirly]

Are they planned to go to Henley? The bay at Twyford isn't wired, so they would be in diesel all day.

First and last services of the day use platform 4 which is wired. So they can run to and from Reading under AC

 

[gallafent]

First and last services of the day use platform 4 which is wired. So they can run to and from Reading under AC

If the usual bay were to be wired, it would make this route a good place to trial a battery version, I would have thought, with the diesels replaced by battery packs with appropriate charging electronics — these trains already have all the necessary kit to connect to 25kV and supply the DC bus, … so the battery modules could be quite self-contained …

 

[Deepgreen]

A test run from Reading to Gatwick and back this morning appears to have gone badly wrong, as the run (which involved several station stands of five minutes, presumably to test door operation, etc.) dropped to 41 late at Wanborough and was reversed at Guildford to curtail the run. Or was there an external factor? The timing data is all over the place on RTT but it's almost back at Reading now.

 

[Bob Price]

Looking at the run on the Railcam timings it was early until it got to Guildford. Seemed to get back to Reading OK. Be interesting to see if the later run goes out.

 

[JN114]

Train was platform interface checking, hence the long dwells at stations (all planned)

Had an engine fault at Guildford, so being on only one engine (sensible) decision taken to send it straight back to Reading after some initial attempts at rectifying it.

Because it’s an out and back schedule the open data feeds don’t seem to have associated it at all correctly.

On industry systems it reported arriving on time at Guildford, stood for a lot longer than booked then went back to Reading effectively 80+ minutes early.

“Badly wrong” is gross hyperbole.

 

[Deepgreen]

Train was platform interface checking, hence the long dwells at stations (all planned)

Had an engine fault at Guildford, so being on only one engine (sensible) decision taken to send it straight back to Reading after some initial attempts at rectifying it.

Because it’s an out and back schedule the open data feeds don’t seem to have associated it at all correctly.

On industry systems it reported arriving on time at Guildford, stood for a lot longer than booked then went back to Reading effectively 80+ minutes early.

“Badly wrong” is gross hyperbole.

Thanks. However "appears to have gone badly wrong" was not "gross hyperbole" from the data I could see. An engine problem/failure and a drastically-curtailed run could well be described as "badly wrong".

 

[Bob Price]

That's something we used to see on the TfW testing, one engine goes down so get back to depot. Wonder how far or how efficient a unit could be on one engine? If one went during service could it continue to it's destination?

 

[MarlowDonkey]

If the usual bay were to be wired, it would make this route a good place to trial a battery version

Platform 5 at Maidenhead is already wired, so testing on the Marlow branch could also be possible. It's about a fifty minute round trip, except in peak hours when one shuttle runs to Bourne End and the other does Bourne End to Marlow.

 

[nmsq]

Platform 5 at Maidenhead is already wired, so testing on the Marlow branch could also be possible. It's about a fifty minute round trip, except in peak hours when one shuttle runs to Bourne End and the other does Bourne End to Marlow.

Except getting a 4 car unit to reverse at Bourne End which can only accommodate a 2 car reversal for Marlow would be very interesting.

The line is also electronic token / staff so too tight to fit a test train between Maidenhead and Bourne End.

 

[spark001uk]

Talking of reversing, 5Q12 only appeared to make it to Ash yesterday, where it was reversed and sent back home. Something amiss?

 

[aleggatta]

Talking of reversing, 5Q12 only appeared to make it to Ash yesterday, where it was reversed and sent back home. Something amiss?

Is this the same working discussed between posts 982 and 985 above?