That surprises me, having watched a couple of the early test runs last summer. I watched 943 making good speed up the 1:100 from Shalford towards Chilworth, and again at the top of the 1:96 from Dorking towards Gomshall. In both cases I'd say the speed was comparable with the Turbos.
So that's physical and industrial relations failures in this whole sorry saga! What happened to power-to-weight calculations for the routes likely to run the units? Has it all just been back-of-envelope stuff when designing and executing the conversions? The costs associated with the abortive class 769 NDL introduction must be considerable, including the interminable testing/mileage accumulation runs (and the many failures), platform extensions, which probably won't now see use for years, and all the zoning signs (applied in reverse at Dorking West - see picture). Just another excruciating mess.
Are the gradients on the N Downs more severe than those on the Rhymney line? TfW 769s are now operating routinely on the latter, and keeping to time.
It does depend on which unit is running. The 4xx ones tend to slip a few minutes, the 0xx ones seem OK.
Please keep up at the back. They didn't have heavy diesel engines and full fuel tanks back then! Give me strength
The Northern 769s routinely climb Miles Platting bank (gradient 1 in 47) in service in diesel mode, from a standing start at Manchester Victoria. E.g. 769448 today:
Those diesel engines & dino juice tanks hardly bring a train that was packed & running at 100 mph below the capability of running lightly loaded on a branch line! Even old steam locos can do 1 in 30 gradients on heritage railways with a few coaches, come on have we gone soft?
Exactly!The Northern 769s routinely climb Miles Platting bank (gradient 1 in 47) in service in diesel mode, from a standing start at Manchester Victoria. E.g. 769448 today:
Realtime Trains | 2W44 0730 Southport to Stalybridge | 08/03/2022
Real-time train running information for 2W44 0730 departure from Southport to Stalybridge on 08/03/2022. From Realtime Trains, an independent source of train running info for Great Britain.www.realtimetrains.co.uk
Nope, as otyhers have said, the GWR units are essentially the same weight as the other two implementations for gradient climbing considerations, (unless you want to be really picky in which case the TFW ones would have slightly less adhesive weight owing to the lack of pantograph on the motor ca), in other words, the differences are irrelevant.
Eastwards out of Chilworth with the added complication that it is on a curve.
Nope there's no need for a rack and pinion track on the Bourne End line either:
Where on TFL do 769s run??
None of those factors were known about when specifying the units then? Given the vast attention given to adhesion on the network today I find it amazing that this couldn't have been foreseen, rather than converting them and then discovering it.
The sections you mention, though, are only around 1 in 100. Again, these gradients or the leafy characteristic of the NDL have not changed since the 769s were specified for the line.
Presuming a typo for TfW (Transport for Wales)
Isn't the issue, if there is one, that the 769s weren't actually specified for any particular line?
Yes it was. Thanks for telling the poster because it looks like pointscoring on the typo meant more than understanding the detail in my post.
Are there any significant gradients on the North Downs Line? The route runs along the valley below the line of the escarpment between Redhill and Shalford, crosses the line of the Downs using the gap formed by the River Wey at Guildford, and then runs down the Blackwater Valley towards Wokingham and Reading.
Almost the whole of Shalford to Deepdene is at 1:96 and 1:100.
Well they are driven by the DC equipment (powered by the diesel sets) so they certainly have that.
Yes, and perhaps more to the point, the route is heavily tree-lined (although with major cutting back over recent years). My point is that the railway has decided to use these trains on a route where they may be unsuitable, whether for power or adhesion reasons, and that would seem to be folly. Just obtaining a batch of generic trains for a franchise without proper consideration of their potential deployment is unhelpful, and the NDL does have characteristics which make it worthy of special attention. BTW, are the diesel engines slung under cars with powered bogies (thus increasing possible adhesion) or not? It may not have been feasible if existing electrical kit takes up the space but, if not, that won't help. We were promised these units were "coming soon" (by FGW) when I still commuted on the route in 2017, and I still hope they appear, as the additional capacity would be welcome, but five years is a long time to hope!
No
While recognising the significant issue of smoke drift, the diagrams here suggest it was a third of one of the trailer coaches that carried the smoking area for the short period it was retained.
That is interesting but is there evidence that 769s are struggling because the single motor coach can't move the rest of the train because it isn't weighed down enough?
I can imagine the announcement.
I can't see DC shoes making a massive difference, and I'd be surprised if they've gone to the trouble of removing the transformer from the TfW units - so I can't see a major difference in weight.
Really? Up to what speed? A 317 is definitely faster than a 150 so a 319 should be similar.
319's weren't underpowered more than capable of dealing with the gradient coming out City Thameslink and before they had OTMDRs fitted spirited drivers could easily get well over a 100 out of them on MML. I would accept they were sluggish off the mark and do wonder whether that was because they didn't want to overstress the power electronics from that era. Whats not disclosed with 769's is what the TE curve is when running on the diesel alternator sets but given the two engines together will only deliver 780kW at the output shaft of the engine that will be further reduced at the rectified output of the alternator to less than 750kw I would suggest. So nominally only 75% the rated power of the motors is available but doesn't mean it can't handle the gradients on the NDL just that SRT's will be longer which is why the schedules have been slackened already.
