North Yorkshire Moors Railway General Discussion

Pity, really, that 825 is to return to service in Wilcock's Improved Engine Green.

 

Any thoughts from those in the know about things NYMR as to whether 76079 will remain part of the NYMR service fleet once the overhaul is completed next year? With the arrival of another Black 5 , is 76079 powerful enough for the demands of regular service trains, without being thrashed, and despite its previous "pocket rocket" reputation? The loco was supposed to have cost a considerable amount to purchase, and has not seen too much service. Wondered with the new cylinder and a new ticket if the NYMR might be tempted to offer it for sale to recoup some of their outlay? No ulterior motive for asking, just curious.

Serious question, but the taxi is waiting outside with the clock running.....

46118

 

I don't think there's any question of 76079 being sold on. The additional Black 5 is needed to provide a larger pool of railway-owned locos, not to alter its make-up. 76079 had been visiting the NYMR for years prior to its purchase and was known to be well matched to the needs of the railway - I don't think there is any question of it being "thrashed", and once it has been returned to traffic I would expect it to be working ca. 10,000 miles a year on Whitby turns. I hope so, anyway - it's the closest we can get to the class 3 2-6-0s that were a staple of the line in later years.

 

Not a cat in hell's chance. In actual fact, 76079 is a better bet than a Black 5 simply because it has a fairly similar tractive effort and weighs quite a bit less so it doesn't need as much to drag itself around. A Black 5 is actually a worse bet than any of the Standard Cl 4's because of its weight penalty. It only starts to come into its own league when speeds increase because it has a bigger boiler. Do the maths and you'll find that the best of all, by far, is a Std Cl 4 2-6-4T. In terms of T.E., a Black 5 has only a theoretical 5.73% in hand on an 8 coach diner whereas a Cl 4 tank has a whopping 14.97%.

 

Steve - out of interest, what figures do you use in your calculations: for example, what allowance do you make for rolling resistance on the train etc? (Was after a general method of calculation really, applicable elsewhere…)

Thanks

Tom

 

As the person largely responsible for getting the 80135 fund going back n the early 70s I have to say that I'd love to see the NYMR acquire another. Superb machines and were of course a staple in the BR era. Mind you, a Fairburn would be a nice alternative!

 

There has been no thought of disposing of 76079 - why should there be? While there were a couple of letters in Moors Line trying to make out the loco wasn't big enough "because it makes smoke going up the bank", as Steve says (and am very pleased that Steve answered on the technical haulage ability point), the Standard 4s are ideal for the majority of NYMR services - that is why we have 3 of them!

The overall plan is to be able to have a serviceable fleet of 5 NYMR owned or maintained locomotives of Class 4 or larger, backed up by Lambton No.29 (and No.5!) available for traffic and covering 3/4 of mileage. 75029 will probably end up by tomorrow night having done over 13,000 miles this year, which is just about the maximum that can be achieved with present diagrams and allowing for washouts. There have been very few "down" periods (45428 since returning to traffic in May and hired 61264 have similar records in 2013). Such reliability doesn't happen without hard work and careful planning at both overhaul and maintenance levels, it would also be impossible on a machine which was being trashed all the time!

The purchase of 44806, generously funded by a benefactor, takes the owned fleet to 7, plus 3 maintained by the NYMR (including the 2 Lambton tanks). This should be sufficient to ensure that the 5 in service can be maintained and, if all goes according to plan, this should be first achieved during 2014.

Steven

 

I do a technical presentation on Power to NYMR footplate staff as part of their training As part of this, I present the sums for a train on the 1 in 49 so this is the basis but the principle can be applied to any situation. Taking the coaches first, the gravitational pull is effectively the total train weight divided by the gradient (not 100% but near enough on railway gradients). Don't forget to add the passengers. We can load up to 400 people at times and that is effectively 30 tons, the equivalent of another coach. BR published test data on Mk.1's and, at 25 mph, the rolling resistance is 4.4 lbf/ton. Multiply this by the gross train weight to get the total rolling resistance. Curve resistance is a bit more of a guess as published info varies quite a bit and depends on wheelbase, etc.. I've used 3.6 lbf/ton for a 13 chain curve. Wind resistance is pretty insignificant until you get into very high wind speeds so I ignore it. Adding all that together should give you the drawbar pull required. A 7 coach NYMR train of Mk.1 stock requires a drawbar pull of 13538 lbf at a steady 17 mph on the 1 in 49.
That takes care of the train. The loco is a bit harder. Gravitational resistance is the loco weight divided by the gradient, as for the coaches. For a Black 5 it is 5726 lbf. The internal resistance of the loco is the hard bit. There is published test info for some locos but for a good bed-time read, have a look at this site:
http://freespace.virgin.net/johnk.pb15/Steam Locomotive Resistance.pdf
If you just want a rough estimate, treat a tender as a coach and take the loco as 15 lbf/ton, perhaps a bit more for a slide valve loco.
I've taken the internal resistance of a Black 5 as being 2100 lbf based on 50% cut off @ 17 mph. Add all this lot together and you get a required T.E. of 13538 + 5726 + 2100 = 21,364 lbf (for a 7 coach set). Do the same for an 8 coach diner and it requires a T.E. of 24075 lbf, which is taking it pretty close to the nominal T.E. of a Black 5. The fact that the steepest bit of the climb to Goathland is actually 1 in 42 (although not very long), adds even more to the fun. That's why I think that an 8 coach diner is really a class 6 duty. It speaks wonders for NYMR footplate crews and locos that they do this regularly.

 

Thanks all. Subject aired and duly put to bed.

76079 stays.

How far advanced is 76079's overhaul? I think the last comment I saw was that the new cylinder was fitted or about to be fitted to the frames.

As an aside, a while ago the 9F people were said to be "in negotiation" regarding part of their steaming fee package. has that been satisfactorily resolved? Mighty useful engine to have in regular service, even if not Whitby-bound.

46118

 

Thanks Steve! Exactly what I was looking for.

tom

 

This is a very interesting discussion. My observations from linesiding and travelling is that 76079 seems to go up the gradients faster(easier) than 75029 with a 7 coach load. I have had some real ball breaking climbs with 75029. I know 76079 doesn't have quite the same T.E. 1000lbs less . Maybe its because it has been bored out or maybe its just due to the crews rostered on my various visits.

 

Some very sad news from the NYMR:

http://www.nymr.co.uk/2013/12/tom-and-erica-salmon/

Steven

 

Also featured on the BBC local news.
http://www.bbc.co.uk/news/uk-england-york-north-yorkshire-25550082

 

75029 can be shy for steam at times and if you haven't got 210-220 psi available, it starts to struggle. The 75XXX weren't good steamers, hence the fitting of double chimneys. Actual cylinder and tyre size have a significant effect, as well but I don't have info on what these actually are.

 

When we brought 76079 out of Barry several former enginemen from Sutton Oak (its last shed) swore that it was unusually strong for a class4 and so it was often rostered for a class 5 turn hence its worn tyres due to slipping. Now I don't know how true that was but it's a bit coincidental that soon after Ian Riley put it on the main line it gained the monicker "Pocket Rocket". Of course it does have smaller wheels than 75029 which would make it stronger on hills. Maybe this thread is crossing over into 'Good uns/Bad uns". Ray.

 

Would've thought that just about everything of any consequence on it would've been replaced since then though?

 

76079 is coming back together steadily. The last time I saw it, the new cylinder had been fitted and it was getting ready to be re-wheeled. Work was still progressing on the boiler. The tender has been repainted and is all ready. That brief report was about three weeks ago, though, so it could be much further on by now.

 

Not sure why you'd think that, all the parts that gave 76079 its 'oomph', boiler, cylinders, motion and blast arrangement were unchanged. I don't even remember Derek re-setting the valves when she was first restored. Obviously parts will have changed during the current overhaul so we'll soon see if 76079 is still ' The Pocket Rocket'. Well done to the NYMR lads working on her. Ray.

 

Steve.
Recently on the other forum you posted detail of working out the coal consumption between Grosmont and Goathland.
Would that be of interest here?

 

I did?! You'll have to remind me where. I write too much dribble on these Forums instead of doing other exciting things such as jigsaws or puzzles. However, there's an interesting (to me) discussion on coal consumption going on in the Motive Power thread at the moment which might substitute.