Mintona
Established Member
It was actually mentioned in post #7706, in a reply to your earlier post about getting to Southcote Jn.
Apologies, I’ve been away. I had a flick back a couple of pages but couldn’t see it on a quick glance.
It was actually mentioned in post #7706, in a reply to your earlier post about getting to Southcote Jn.
No need to apologise. It’s easily missed there’s so many posts.Apologies, I’ve been away. I had a flick back a couple of pages but couldn’t see it on a quick glance.
Passing through Midgham a few hours ago, looks like there was work underway just west of the up platform to connect some (supply?) cables to gantries over the top of the OHLE. Assume they come from the feeder station that was built a while back just across the car park from the up platform?
Because the wires aren't yet authorised for passenger service. Drivers have to all be trained up on using the OLE, which will most likely be done on specially programmed driver training ECS moves or similar. Didcot to Wootton Bassett's been live for a good few months now, and AFAIK there's only been one test diagram using the AC from Didcot to Swindon.So, as Bristol Parkway to Paddington is now fully wired, why are the trains still running on diesel west of Didcot?
So, as Bristol Parkway to Paddington is now fully wired, why are the trains still running on diesel west of Didcot?
Signalling interference issues awaiting a solutionBecause the wiring still has to be tested and approved for use by all parties.
So, as Bristol Parkway to Paddington is now fully wired, why are the trains still running on diesel west of Didcot?
Not sure where I got it from either to be honest - I'm still fairly confused by the 80X driver training process, and thought that diesel power and AC power were 2 comprehensively separate modules!There’s no additional driver training requirement - I’m not sure where you’ve gotten that from 59CosG95 - once a driver is AC competent on 80X they can drive it on AC anywhere their route knowledge and Electrification limits allow.
Signalling interference issues awaiting a solution
As far as I’m aware non have been identified on that part of the GWML yet and how will they find out until the 80x runs on the juice? The issue previously was cabling on an axle counter on the Down Main at Cholsey which didn’t show up until the 800s ran a few times.
So, the majority of drivers are now trained to drive in electric mode and the wires are up as far as Bristol Parkway yet it is going to possibly take until December until the new trains can run this section off the wires. Hmm... Mention has been made of the possibility of interference with the signalling systems. How can that be when a massive new signal box has recently opened at Didcot - along with new signalling? This project seems to be taking forever. How many years late are we now in getting the GWML electrified to Cardiff? Wonder what Brunel would make of all this - and his name on the side of a Japanese train?
So, the majority of drivers are now trained to drive in electric mode and the wires are up as far as Bristol Parkway yet it is going to possibly take until December until the new trains can run this section off the wires. Hmm... Mention has been made of the possibility of interference with the signalling systems. How can that be when a massive new signal box has recently opened at Didcot - along with new signalling? This project seems to be taking forever. How many years late are we now in getting the GWML electrified to Cardiff? Wonder what Brunel would make of all this - and his name on the side of a Japanese train?
So, as Bristol Parkway to Paddington is now fully wired, why are the trains still running on diesel west of Didcot?
Regarding signalling interference, I believe the main issue holding up electric services to Swindon are the pan-up/down beleizes around Steventon, and interference between these and the axle coutners. To be fair to the resignalling project, I don't think the system was originally designed with automatic, on-the-move pan-up/down of the 800s in mind (note I'm not a signalling engineer, so may be talking rubbish).
And note, like the TASS (Tilt Authorisation and Speed Supervision) system on the WCML, these are standard ETCS balises sending national extension messages, for the sake of compatibility with ETCS once rolled out.They’re spelt “Balises” - the train was designed for automagic pan up/down on the move but you’re right that the configuration at Steventon wasn’t in the original infrastructure design.
Ah, you're quite right - I did say I wasn't in signalling after all!They’re spelt “Balises”
Until the safety validation is completed by the ORR, the OHLE can only be switched on under controlled test conditions. The wording is “the OHLE must be considered live at all times from xyz date” - that doesn’t mean its on 24/7. Those that need to know it’s isolated will do so, everyone else should treat it as live.
Once it’s signed off by the ORR it will switch to being normally live as it is east of Didcot. Until it is normally live no train operators will be running AC trains on it, except under controlled test conditions.
These safety validations have happened under every electrification project since the 1950s (at least).
There are no inherent interference issues on the GW electrified routes - as FGW_DID mentions there have been a couple of minor installation issues with Axle Counter cabling that have induced interference, but that’s equipment that’s not been installed per design - the equipment when installed properly is fully AC immune.
The delays to the electrification programme are down to financing and costing issues - Lack of money has caused overruns in immunisation works which slowed installation which protracted to programme. The lack of money at Network Rail can be solely laid at their financier - central government. Brunel was a visionary privateer who saw the railway as a great way of catalysing the new technologies in development. He also had his fair share of cost and time overruns on the construction of the Great Western and by all accounts was pragmatic about it convincing stakeholders that the overruns were worth the short term pain. I think Brunel would be quite content with how his railway is advancing technology; and certainly wasn’t afraid to use foreign contractors to get work done.
I’m not sure why people think everyone in Victorian times was a bristling nationalist...
And note, like the TASS (Tilt Authorisation and Speed Supervision) system on the WCML, these are standard ETCS balises sending national extension messages, for the sake of compatibility with ETCS once rolled out.
Why can't a brand new system with brand new parts work is beyond me
As has been said many times on many threads today, this incident has occurred under the "old" (1990's) OHLE that is still mostly in place between Paddington and Airport Junction. The "new" heavily-constructed OHLE west of there *should* be much more resilient (as each wire is suspended individually, rather than by other wires that cross the spans).
Looking this up further, contrary to what I'd previously read, while tilt is done using Packet 44, pantograph control is indeed done using Packet 68.Really? I wonder what the rationale for this was rather than using the standard ETCS functionality (Packet 68).
Ah I see. how reliable has the "new" OHLE infrastructure been since it's been put in?
Outstandingly so.Ah I see. how reliable has the "new" OHLE infrastructure been since it's been put in?