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12 minutes ago, Titan said:

Trouble is, 3 or 4% increased revenue in the near future is not likely to be worth anything near as much as it was a few months ago...

In the short term no, but we need to look further ahead.  If we just look at the next few months and take that as the new normal we would probably cancel all infrastructure enhancements as not worth it but traffic levels will steadily increase and our sights need to be on the long term.

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4 hours ago, phil-b259 said:

If there was no aspersions for 140mph running then the OLE could have been made cheaper - and equally there would have been no need for the class 800s to be designed for 140mph running.

 

Agreed faster running is not the sole reason for ETCS, but if you are going to the trouble of installing it and the trains are 140mph ready then why not?

That question should probably be directed at whoever specified the OLE and the trains.  

 

Maybe the ETCS could include some 140mph provision at little extra cost.  I don't think it would need any extra equipment although the "software" might have to be more complicated to issue longer movement authorities.  But as I said I very much doubt it will be very useful because of the mix of fast and slow trains, with far more intermediate station stops (and more trains in total) than there were back in the 1970s.  

1 hour ago, class26 said:

BR always reckoned that 1 minute of time saved increased revenue by 1% so if that still holds then I would say even 3 or 4 minutes saved is worth it.

It was actually 1% of time saved increasing revenue by 0.9%, but for a journey like London-Bristol it would come to roughly the same answer.  But BR didn't usually have the problem of finding enough empty seats to carry the extra passengers.  

1 hour ago, Titan said:

Trouble is, 3 or 4% increased revenue in the near future is not likely to be worth anything near as much as it was a few months ago...

 

1 hour ago, class26 said:

In the short term no, but we need to look further ahead.  If we just look at the next few months and take that as the new normal we would probably cancel all infrastructure enhancements as not worth it but traffic levels will steadily increase and our sights need to be on the long term.

I hope and believe we'll be out of social distancing within a few months - passenger densities in the Far East are already back close to normal with little sign of infection being passed (everyone wears masks).  

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On 23/05/2020 at 11:27, rodent279 said:

I think it's a classic case of people with the right connections making the right noises. If I objected no one would take a blind bit of notice, but if the right person makes the correct complaints to the right people, they get noticed. 

Quite - I remember standing on the platform at Bedwyn back in 2014?? en-route to a possession planning meeting at Reading just after it was announced that the wires wouldn't reach further than Newbury and overheard a suited chap say to his travelling partner "Have you heard we won't be getting electrified" ……………………… "Yes, I've SPOKEN to Steven about rectifying that" came the emphatic reply ………

 

There's a lot of that sort of thing in West Berkshire & East Wiltshire ………………………………. they wear hats to work still :D

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2 hours ago, Edwin_m said:

 

Maybe the ETCS could include some 140mph provision at little extra cost.  I don't think it would need any extra equipment although the "software" might have to be more complicated to issue longer movement authorities. 

ETCS level 2 isn’t that much different to a traditional fixed block system. You simply need enough free blocks between you and the preceding train to give a safe braking distance (with margins). If you kept the standard 1020m block length then just adding an extra block between trains gives you the margin required to run at 140 rather than 125. (Simplified but close enough). Essentially what BR did with flashing greens on ECML. The software won’t be any more complicated. 
 

The mixture of train types will be the killer for higher speed. Level 3 (moving block) offers benefits here. 

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1 hour ago, david.hill64 said:

ETCS level 2 isn’t that much different to a traditional fixed block system. You simply need enough free blocks between you and the preceding train to give a safe braking distance (with margins). If you kept the standard 1020m block length then just adding an extra block between trains gives you the margin required to run at 140 rather than 125. (Simplified but close enough). Essentially what BR did with flashing greens on ECML. The software won’t be any more complicated. 
 

The mixture of train types will be the killer for higher speed. Level 3 (moving block) offers benefits here. 

 I was thinking more of something like an automatic route setting system.  Currently they aim to have all trains with at least one green signal ahead of them, but if they did that with all trains on a "five aspect" system then routes over junctions would have to be set that much sooner with a capacity penalty.  The system needs to start to know which trains are 140-capable and only give those the extra movement authority.  

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4 hours ago, Southernman46 said:

Quite - I remember standing on the platform at Bedwyn back in 2014?? en-route to a possession planning meeting at Reading just after it was announced that the wires wouldn't reach further than Newbury and overheard a suited chap say to his travelling partner "Have you heard we won't be getting electrified" ……………………… "Yes, I've SPOKEN to Steven about rectifying that" came the emphatic reply ………

 

There's a lot of that sort of thing in West Berkshire & East Wiltshire ………………………………. they wear hats to work still :D

 

"We don't blow whistles at people from Newbury,  General Manager" - G T W Fiennes

 

David 

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5 hours ago, Southernman46 said:

"Yes, I've SPOKEN to Steven about rectifying that" came the emphatic reply ………

 

Why did they want it on DC ?  :D

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32 minutes ago, figworthy said:

Why did they want it on DC ?  :D

The lines to the North use AC. If they used the same system in Berkshire, any working class ruffian could go down there. They'll be nicking the wheels from the trains!

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22 hours ago, david.hill64 said:

The mixture of train types will be the killer for higher speed. Level 3 (moving block) offers benefits here. 

Not really. The killer for line capacity is the difference in speed between the fastest and slowest trains and adding another 15mph to that is liable to reduce the line capacity. All that ETCS 3 really does is remove (or reduce)  the hysteresis in train headways due to signals being spaced at significant distances.

 

Jim

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1 hour ago, jim.snowdon said:

Not really. The killer for line capacity is the difference in speed between the fastest and slowest trains and adding another 15mph to that is liable to reduce the line capacity. All that ETCS 3 really does is remove (or reduce)  the hysteresis in train headways due to signals being spaced at significant distances.

 

Jim

Absolutely so.  Having moving block does nothing to resolve speed and acceleration differentials between different types of train or differences in the lengths of trains.  If all trains are exactly the same with common characteristics (length, acceleration, maximum achievable speed at any specified location, and braking/deceleration rate) then moving block can increase capacity.  But as soon as you introduce station stops, particularly dissimilar stopping patterns across, say, a standard hour of a timetable, you start to erode the benefits of moving block as any timetable graph would instantly show.  If you then take it a stage further and move it to teh current operations area instead of the planned you introduce further inconsistencies because it is difficult, short of using physical force, to ensure consistent station dwell times for passenger trains and to ensure that all factors remain consistent in all weather conditions.

 

If, for example, you introduced moving block to the city loop in Sydney NSW the only advantage it would confer, provided it comes with automatic train operation, is to confer absolute consistency of driving performance and signal operation across a 100% common fleet of train types (you'd also need that commonality for maximum advantage) because the existing fixed block situation provides massive flexibility in permissible speeds between any two signals and any two stations thus allowing very tight headways using 5/6 aspect signals at relatively close spacing.

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19 hours ago, jim.snowdon said:

Not really. The killer for line capacity is the difference in speed between the fastest and slowest trains and adding another 15mph to that is liable to reduce the line capacity. All that ETCS 3 really does is remove (or reduce)  the hysteresis in train headways due to signals being spaced at significant distances.

 

Jim

Agreed: the benefit isn't great but it is there, particularly in recovery from perturbations. Given the overcrowded nature of UK rail, these happen frequently.  Yes, you can do the same in a fixed or virtual block system, but moving block is less hardware intensive compared with a traditional system with close signal spacing and these days probably cheaper (in metro applications at least) than fixed block: hence the move to moving block in most new metros. Train integrity detection is still a bit problematic for main line applications although Bombardier did manage it for its ETCS level 3 look alike system (same functionality, non-compliant carrier).

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I've become aware that class 88's are appearing on the Bridgewater flasks (this may have been happening for some time, but I've only just become aware of it!)

I know that particular train doesn't spend long under the wires, but are class 88's allowed to work pan up under the wires on the GWML? If say the train was diverted via Swindon and Didcot, could the 88 work in electric mode?

 

Cheers N

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2 hours ago, rodent279 said:

I've become aware that class 88's are appearing on the Bridgewater flasks (this may have been happening for some time, but I've only just become aware of it!)

I know that particular train doesn't spend long under the wires, but are class 88's allowed to work pan up under the wires on the GWML? If say the train was diverted via Swindon and Didcot, could the 88 work in electric mode?

 

Cheers N


Not yet, they are not approved to use the GW OLE yet, nothing is apart from Class 80xs and Class 387s
 

Simon

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39 minutes ago, St. Simon said:


Not yet, they are not approved to use the GW OLE yet, nothing is apart from Class 80xs and Class 387s
 

Simon

Why do they need to be approved separately? 25kV AC through OHLE is 25kV AC through OHLE isn't it?

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3 minutes ago, DK123GWR said:

Why do they need to be approved separately? 25kV AC through OHLE is 25kV AC through OHLE isn't it?

I suspect that in Todays world each typevof piwer will have to be approved separately with regard to pantograph type, power draw etc.

 

Jamie

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lol... and there I was thinking that that might of had some sort of standards that could be fairly universal... :blink:

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Not to mention compatibility with signaling and everything else on the route.  Electric running generates return currents which can affect signaling equipment, so just because it's approved on diesel doesn't mean it is on electric.  

 

In practice it ought to be pretty straightforward to get this approval, as the GWML has been upgraded to the latest equipment so ought to have good levels of immunity to things like traction harmonics in the rails.  But as stated all new traction has to go through the approval process for each route it is intended to run on, which costs time and money for admin even if straightforward technically.  

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53 minutes ago, jamie92208 said:

I suspect that in Todays world each typevof piwer will have to be approved separately with regard to pantograph type, power draw etc.

 

Jamie

More to do with interference to signalling, I think you'll find. 

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It's all too do with safety cases, and the bottom line is responsibility in the event of an accident.

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And it keeps lots of consultants in lucrative work so they don't need to be furloughed.

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1 hour ago, Grovenor said:

And it keeps lots of consultants in lucrative work so they don't need to be furloughed.

 

It would not, normally, require any bleeding consultants. It is a standard requirement of traction approval processes, and is suitably staffed within NR, and, I would presume, within the leasing company providing the loco or other traction.

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6 hours ago, DK123GWR said:

Why do they need to be approved separately? 25kV AC through OHLE is 25kV AC through OHLE isn't it?


Hi,

 

In the case if the 88s, they are not approved to run in either Diesel or Electric Modes on the electrified sections of the GWML (or at least, they  weren’t when we did Steventon). When they come to look to run them, the need to make sure they are compatible with the OLE.

 

For other units and locos, if they have the same pantograph as a Class 80x or Class 387, then the OLE approval is just a case of ‘it’s the same as the ones already approved so it’s fine’. If they have completely different pantographs (as is the case on the 769s), then a compatibility assessment has to be carried out to ensure the interaction between the OLE and Pan doesn’t cause damage to each other
 

5 hours ago, Edwin_m said:

In practice it ought to be pretty straightforward to get this approval, as the GWML has been upgraded to the latest equipment.

 

I know you are talking signalling interference, but the stuff being new doesn't necessarily mean it is easy! The 387s (which are used quite happily on other OLE routes) had lots of carbon strip chipping due to the higher tension in the GWML contact wire.
 

1 hour ago, Mike Storey said:

 

It would not, normally, require any bleeding consultants. It is a standard requirement of traction approval processes, and is suitably staffed within NR, and, I would presume, within the leasing company providing the loco or other traction.

 

Yes, it’s usually NR, Manufacturer and TOC staff that do it.

 

Simon

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7 hours ago, bimble said:

lol... and there I was thinking that that might of had some sort of standards that could be fairly universal... :blink:

Like the Technical Standards for Interoperability? 

 

Jim

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8 hours ago, bimble said:

lol... and there I was thinking that that might of had some sort of standards that could be fairly universal... :blink:

 

standards.png

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Some years ago there was an international standard for electrical conduit (there probably still is but I have been out of standards matters for 13 years now). The trouble was there were dozens of categories so everything from cardboard to heavy duty steel complied. So it was absolutely no use specifying "must comply with ISO xxx. That's what happens when you try to write a standard to cover every case. I seem to remember that the cardboard option was to make the Italians happy but I may have misremembered.

Jonathan

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