769002 was dragged to Canton by rail on 14th March, and iirc the gauging issue was discovered when the unit got to Canton. It is hard to keep up now, I agree.
To add to big all's comment, the gauging team can accept some sub-standard clearances in the short term to issue a temporary gauge certificate (on the basis that track will not move substantially in the next 12 months) but cannot accept them for a permanent "30 year" gauging certificate, which needs to take into account maximum tolerances. Also, the delivery gauging cert may not have considered passenger footsteps fitted / crush loading etc. which can increase the swept envelope.
You're going to have a long wait then, since there's no plans to run them over Chat Moss. Even if they do run that way for any reason, they'll still be on AC so no difference from now (which is to say from 319s).
As 142s have substituted for 319s it's a possibility. In hindsight, I shouldn't have been location specific. My point was that if an almost empty 319 struggles to get away then a 769 whether on AC or gen-set will definitely struggle as there are quite a few tons difference (2x8 tons has been quoted previously) between a 319 and a 769.
2x8 tonnes is a very small part of the 143 tonnes total class weight when empty with 35% of that weight available for adhesion. Load it with seated passengers, that another 24 tonnes. If it is crush loaded, it would weigh upwards of 200 tonnes and the adhesive weight would still be over 29%. Of course some drivers have a better touch than others at reducing wheelspin, but the "quite a few tons difference isn't really much in the big scheme of things.
Yes, provided that the unit was not itself damaged by the OLE failure and (as you say) that the OLE failed in such a way as to allow trains to pass safely, it should allow continuation of service. The only issue I think would be how much fuel was available, although you'd hope that the re-fuelling policy would ensure there was enough at the start of the day to run the whole diagram on diesel if required.
Well the 319s regularly ran up the 1:27 to Blackfriars from a standing start at City Thameslink. About three quarters of the gradient is exposed to the elements. Similarly there's the 1:29 (ISTR) from St Pancras up to Dock Junction, with about one third exposed. Passenger loading at those points was at a maximum on every evening weekday peak.
Yes the biggest thing that stops diesels / bimodes running on electrified lines during OHLE failure is there are often other 'failed' electric trains en route blocking the line. But so long as the line is clear they are fine.
The Wigan to Alderley Edge service is desperate for decent rolling stock after a year of Pacers, particularly after those in electrified track south of Manchester feel as if they've gone back decades with that service. I'm not so sure about the Styal Line services. Arriva are committed to operating all services to/from Manchester Airport with either 195s or 331s going forward. Not to mention the Franchise Agreement is quite particular in the requirements of rolling stock for Northern Connect services to/and Manchester Airport - sufficient luggage space, swift acceleration etc. The 319s are slow enough so it will be interesting seeing how the 769 compares with the extra weight to be carried.
Yep. And yep. Supposed to be happening at some point, but I'll believe it when I see it.
its suggested at present only stationery change over will take place
Arriva's original rolling stock plan for Northern assumed that Lostock Jn - Wigan NW, and Victoria - Stalybridge, would be wired by December 2017, enabling Wigan NW - Stalybridge/Alderley Edge services to be worked by 319s. If Network Rail had delivered that as promised, the 769 (and this thread) would probably not exist.
Is Arriva really committed to operate the Liverpool - Crewe via Airport stopper with 331s? It is not a Northern Connect route and I thought that 319s were the long term plan. And AFAIK there are no plans to operate 769s to the Airport (unless thrown up by the Northern random unit generator).
No. The whole route of these services from Bolton to Alderley Edge is under the wires. It's important to remember the 'south of Manchester' part as well. It will only be Bolton to Wigan that has to be run on diesel.
The diagrams however are written to interwork with Wigan - Stalybridge ie a train will do Wigan to Alderley to Wigan to Staly to Wigan.... and repeat - Victoria to Staly isn't wired either.
Welcome to the world of post-Thatcher-era privatisation, deregulation, competition and fragmentation. Works a treat doesn't it.