Load Test and Inclines

In message , snipped-for-privacy@mwfree.net writes

On my layout, the maximum gradient is 1 in 75 and goes on for 30 feet. I have no problems with Bechmann 56XX and 66XX 0-6-2T locos pulling 11 coaches or 45 wagons up this incline.

Mind you, my 72XX 2-8-2T (built from a Nu-Cast kit) will handle 20 coaches or 70 wagons up this same incline.

wrote

Interesting how we always expect a model to perform better than the prototype.

A gradient of 1:30 is generally regarded as generous on a model railway, but would be a real challenge on the prototype. Even the notoriously tough climb from Grosmont to Goathland on the North Yorkshire Moors Railway is only 1: 49.

A prototype curve of 22 chains radius (176 yards) is regarded as a minimum for use in sidings and dock areas and mainline curves are very much greater, but a 22 chain radius scales to around 7 foot on a OO-gauge railway, and that would be considered *extremely* generous.

Personally I'm more than happy if a model loco will produce similar performance to the prototype.

John.

I submit that on or about Mon, 25 Jul 2005 19:26:55 +0100, the person known to the court as "John Turner" made a statement ( in Your Honour's bundle) to the following effect:

Too true. I tried to work to 1:100 but went to closer to 1:50 in a couple of places, and even then on a 12ft square hardly any of it is flat! The Hornby A3 has most trouble, the 8F has least. The 8F will pull a bus if you pile in enough lead to give it traction :-)

Guy

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Seems to be some mistake here! The Railway Inspector's rules require continuous check rails on curves of 10 chains radius or less used by passenger trains and there were plenty of these. Most main line locos and coaches had minimum curve capabilities at very slow speed around 4 chains. This would also be the minimum for sidings on the railway proper. Dock areas and industrial sidings could be much tighter and published tables for industrial turnouts get down to 1:2.5 crossings (frogs) with a radius through the turnout of 58ft, 9 inches in 4mm scale.

NB. 1 chain is 22 yards or 66ft hence: 4 chains is 88 yards or 264ft. in 4mm scale approx. 3.5ft. 8 chains is 176 yards or 528ft. in 4mm scale approx. 7ft. 10 chains is 220 yards or 660ft. in 4mm scale approx. 8.7ft. 22 chains is 484 yards or 1452ft. in 4mm scale approx. 19ft. Thus you were right about the 176 yards but not the 22 chains. The tightest industrial turnouts not even Hornby would use! Actually there were 1:2 turnouts even tighter than 58ft radius but I don't have the figures to hand.

Keith

Make friends in the hobby. Visit Garratt photos for the big steam lovers.

Tim

"Tim Illingworth" wrote

Got my arithmetic and facts wrong on that one then. Sorry.

John.

This has all been gone through earlier on. There are only two ways to increase the hauling power of a model loco, 1, increase the weight on the driving wheels; 2, increase the co-efficent of friction between the wheels and the rails (i.e. the dreaded traction tyres). No.1, for the average British outline steam loco is often difficult to do, there is not a lot of spare space inside the boiler if the motor is there. Motor in tender, Cardan shaft drive to loco. wheels, boiler stuffed full of lead would be an answer, but not easy to do. As diesels have large, boxy bodies, it is easier to weight them up than for steam locos. which is probably why the diesels performed better in the test. Get the kitchen scales and weigh your locos and compare the steam and diesel models. Regards, Bill.

"John Turner" wrote in message news:dc3mab$og1$ snipped-for-privacy@newsreaderg1.core.theplanet.net...

"William Pearce" wrote

There is another way and that is to ensure that all rolling stock is fitted with free-rolling metal wheels, although I admit this doesn't increase the hauling power per se, it does generally allow a longer train to be hauled.

John.

Bachmann engines aren't exactly lacking in weight, if anything I would say heavier than the Hornby locos so it must be down to the wheels. Why the 2-6-4T was successful whilst everything else failed puzzles me. I had fully expecter the Hornby tender drive locos to be the worst and in fact they were the best. What I intend to do is increase the length of the incline as much as I can, I can probabley manage another 3 feet at least, the down side is that this will be on a curved section. The other is to have a cut-off section on the layout that shortens the overall length of track available but avoids the inclines. Engines that can't manage the incline will be limited to the shorter part of the layout.

Kevin

"John Turner" wrote in message news:dc7hk8$j3s$ snipped-for-privacy@newsreaderg1.core.theplanet.net...

There was quite a good article in one of the French mags concerning 'rollability'- one of the things it pointed out was that, even with pinpoint steel axles, it was possible for burrs on the axle ends and on the inside of the bearings to inhibit the movement of the wheel sets. Indeed, the author quoted an example of a Jouef wagon which would not roll of its own accord when taken out of the box and placed on an incline. Measures suggested included cleaning up bearings and using a dry PTFE lubricant from Labelle. For myself, even when fitting brass bearings, I use a tool from my local model shop (Hythe [Kent] Models to 'true' the bearings. This consists of a piece of round tool steel, the length of a normal axle, with both ends machined to a profile the same as a normal pin-point. One end has a cutting edge machined into it which effectively shaves the bearing into true. If there is a problem, it is that the stock is so free-running that it has to be stabled carefully to avoid runaways. The French article also suggests that we are inclined to ballast our vehicles too much, quoting NMRA/NEM norms as follows for HO scale:- NMRA Minimum mass 28.35 grammes plus .56 gm per mm of length over headstocks NEM norms .40 gm/mm of length A quick 'back of envelope calculation suggests that a short wheelbase British wagon, at 20' (80mm) over buffers should weigh 73 gm under the NMRA system and 32 gm under the NEM one. I would suggest a mean between the two of 50gm, or about 2oz would be about right. Brian

In message , BH Williams writes

I like to dismantle my wagons prior to converting them to Kadee couplings, and when I put then back together again, I leave the weights out. Wagons treated in this manner end up at about 35g., which seems to suit the NEM formula very nicely.

I add weight to around 65gms! (105mm long wagon) I allow a variation of minus or plus 33% on that figure to allow for removable loads and wagons which are difficult to weight. IOW the heaviest wagons are double the weight of the lightest. My formula is 15 gms + 5 gms per cm (1/2oz + 1/2oz per inch near enough) (80mm would be 55gms/2oz) As a wagon gets a side pull on curves (vaguely) equivalent to it's length, I consider they need more weight. It works for me with long (20-25 wagon) coal trains and tight curves in my hidden staging yard operating NEM to NMRA RP25 standard wheel sets.

I have come the same conclusion as the author of the French article and also agree for a 00 UK 4 wagon 50g is about right. I use the H0 NEM formula for passenger carriages and 0.57g/mm for goods wagons. I model H0 and use Kadee's. Any linear formula within reason is the best option, therefore Greg's formula like the NMRA's one is not the best. Under test conditions I have pushed an equivalent train length of over 100 4 wheel wagons without derailment. The first wagons were 4 wheel wagons. Using the NMRA style of formulas can result in 40% decrease in maximum train length.

On the subject of the Bachman steam locomotives, If they have springs on the bogies, remove the springs. This will improve tractive effort significantly. The other area to check is the free rolling of the tender. Further information about tract effort can be found on my web page.

I've gone with the non-linear formula for two reasons:

- All vehicles have two or more axles (ok, I know one exception :-) The bearings have a certain amount of stiction which is both significant and not necessarily proportional to weight/length.

- I use close coupling mechanisims, which are not proportional to weight.

I work over my locos to provide the required amount of tractive effort, usually by adding weight. Block length is the first limiting factor on my layout and that brings train lengths to around 50-33% of prototype lengths on 1:40 gradients.

I have to disagree with this point, bogies and trucks should be sprung rather than weighted for good trackholding. However, correct spring tension is important, which proprietry manufacturers normally get wrong. 20-25 grams per axle is about right. I'm afraid we're going to have to agree to disagree on that point, Terry.

It's a long time since I've looked inside a Hornby tender drive, but I suspect that they would have quite a lot of ballast therein. I still advise, weigh the locos and check the gradient performances vis a vis the weights. Alternatively, run a banking engine on the graded section, this could make an interesting working. Regards, Bill.

In message , Greg Procter writes

I like running "very long" coal trains (40 wagons or more), but my minimum radius is 3 feet 6 inches so I guess I don't have the same problems that you do.

Found the same thing. When I was building my layout a put a test track in which rose 3" in 6' (or something like that , can't remember now). The best performer pulling 6 coaches was a tender enfined Hornby Mallard circa 1980 followed by the same vintage Wrenns with the late model Bachmanns either failing or struggling to climb the rise.

Jim

----- Original Message ----- From: mindesign Newsgroups: uk.rec.models.rail Sent: Friday, July 29, 2005 5:00 PM Subject: Needed: 9F Boiler end

Hi all

I'm not sure what it is called, but I have lost the damn end from my 9F 2-10-0 Evening Star loco. Anyone have one laying around, or can remove on from a damaged body they no longer need? I am happy to pay for it. Alternatively, can folks point me to where I can buy a used one.

Thanks

Steve

G'day again Steve, I should have these in stock. If you want one email me and I will look tomorrow. Thank You Graeme Hearn, P.O. Box 20, Yerong Creek, New South Wales, 2642, Australia. Phone: 61 2 69 203 726 Email: snipped-for-privacy@bigpond.com Webpage:

Bearing friction is proportional to wagon mass. Wagon mass is not the only variable.

It sounds like the close coupling mechanisms might decrease the overall length of train that can be run. A non linear formula does not solve this problem except for fixed train compositions. For example putting a heavier wagon always on the front of the train. A simple linear formula is the best option for trains in which the wagon location is not fixed. Another problem with not using a straight length to weight ratio is when you have train made up of small 4 wheel wagons it will have a greater mass compared to a train of the same length made up of bogie wagons. This is the opposite of the comparative mass of loaded prototype wagons. Also the bogie wagons were often a more modern wagon, and had a higher axle load.

Terry Flynn

DC control circuit diagrams

HO scale track standards