Not sure I understand you. Surely the tractive effort that can be delivered when adhesion is low is the only thing that matters?
Maximum tractive effort alone doesn't tell you much about the speed range it can be delivered. I'd guess a 93 will probably be able to keep maximum tractive effort up around 35mph and will probably beat a Class 66 above 15mph in electric mode.
Sounds right. Power = Force x speed = 290kN x 15.9 m/s = 4600kW
The key point is poor adhesion limits the maximum tractive effort per axle hence more axles helps. Also adhesion tend to improve with successive axles hence more powered axles help.
When they announced the 93, ROG said that Stadler persuaded them that, with modern wheelslip control, they could get away with four axles and still get traction in poor adhesion conditions. We'll just have to see how that pans out in testing, but the omens are not good.
Thanks. I was looking for that chart this morning and couldn't find it
Seems to work fine in the rest of Europe, where Bo-Bo TRAXX and Vectrons dominate the freight market. Though admittedly on the more challenging Alpine stretches they normally just stick another on the front (thus doubling power to ~13MW over 8 axles)
According to https://www.railforums.co.uk/threads/class-88-ukdual-eurodual.107049/post-2843016 the 88 performed nicely and I don't see a reason, why the 93 would not.
If I compare it to a random "standard" european AC-locomotive with four axles (they all are similar in the end) everything between 1200-1300t should be fine going up Shap (my TOC values, others might vary).
Is that from a standing start, or with a run up?
Both.
Very impressive
16-1800t is the normal trailing weight in the timing load for a 775m train...
One post refers to testing before entry into service and the other describes what has been shown to be needed in practice. The GB rail network on a damp autumn day has proven the need to double head because of low adhesion in practice compared to adhesion testing in Velim referred to 8 years ago in the class 88 thread.
An 88 is rated for 1400t on the northern WCML. So shorter / lighter trains and the need to double head in autumn...
That should work fine then as our tables are made for longer inclines than Shap. Short inclines often have special tables with higher acceptable loads. Some comparable routes are rated for 1750 tons. But that is up to the TOC.
Good, didn't realise it was that high.
Er???
ROG said it was a new system, with better performance.
The 99 weighs 116t, compared to the 93 at 86t. Slightly less axle load (19.5t vs 21.5t), but six axles instead of four. Do we know what TACs for these classes will be yet?
Not if the 93 is rated to get a maximum length intermodal over the hills. I don't see how the 99 could haul more than that. Which is why the performance on gradients under poor adhesion is so important.
ROG have had a lot to say about the wonderous properties of these locos. They also had plenty to say about their logistics business, 100mph intermodal trains and whatever else - which hasn't happened.
Beacon's data sheet https://beaconrail.com/en/fleet-item/cl-99/ says weight of 113T over 6 axles, or 18.833...t per axle. RA isn't quite as simple as a strict t/axle loading, but it's a fair guide. The limit mentioned on Wikipedia for RA5 is 19t axle loading, although the NR pages cited return a 403 error.
Must be more to it than just axle load, as you say. A 47/3 was 113t but RA6.
They compared it to a 66 not an 68, 70 or 88 all of which have sophisticated three phase motor control
No 113 tonnes as others have pointed out
it won't be
The 99 will be much faster so easier to path
Every modern existing GB freight loco already has that tech: 70, 68 and 88Which is why the performance on gradients under poor adhesion is so important.
EDIT:
93 traction control was described here:
Class 93: the science of modern traction
Rail Operations Group has not ordered a fleet of class 93 tri-mode locomotives just because of the funky livery. The Stadler-built locomotives, due for delivery…www.railfreight.com
The formula is fairly complicated but 99 has even axle loadings 47 didn't (close but not completely matched) and modern locomotives are better at reducing bogie pivoting.
I suspect the difference is probably mostly down to the 10% difference in gearing (100mph max for the 88, 110mph for the 93). The motors will have an upper limit on torque/current, with higher gearing that translates into lower maximum axle torque/tractive effort.
Marvellous footage. Thanks for posting
I cannot wait to see these working intermodals down the North London line.
