The pulling power of Maerklin.

QUOTE (neil_s_wood @ 4 Mar 2007, 05:17) <{POST_SNAPBACK}>I told you recently on another thread this is because US outline is considerably larger and heavier than European including UK outline. This still hasn't changed. In order to get decent traction you need weight or something which will give purchase on the track. If your loco is light the wheels will spin wildly while the train doesn't move. I wont give any specific examples as it may be distressing for some.

Unforunatly Neil, it does not matter how many time you tell some people some simple facts they are incapable of taking it in.

As for the suggestion (made by Ravenser) that I spend £100 at a "box shifter" for a couple of locos (that I have no use for anyway) to try to prove a point to people who won't admit to facts - I don't think so. I'll wait until I can borrow a couple of candidates - unless someone wants to buy a couple of "tested" locos afterwoods - or loan me a couple ???

Due to previous problems (on other threads elsewere) with a Heljan HO locomotive & their s y attitude I will never buy another Heljan product OO or HO.

I seem to recall that the late Model Railway Constructor used a spring balance or something to test "drawbar effort".

Neil;

I'm not sure this is true - certainly for not Type 5 diesels.

Hornby 60 - 11 inches long over buffers , weighs 700g

The Bachmann 66 is pretty similar in terms of length and weight, and I'd expect the Bachmann 40 mentioned above to be in the same league as well. The Heljan 47's not far off either

Even the powered coach of my 2 car Bachmann Turbostar DMU scales in at 1lb (450g). This is the same mechanism as Bachmann use in the 158 and Voyager , so the worst load it faces is a 5 car Voyager - powered coach + 4

Bachmann's 20 is a mere 425g , but this is a narrow bonneted loco and the real things are only 1000hp

These are all common , widespread classes, so very much "bread and butter" models for a 4mm modern image modeller

Steam isn't my scene , but state of the art OO kettles aren't light either

QUOTE (Ravenser @ 4 Mar 2007, 20:28) <{POST_SNAPBACK}>Neil;

I'm not sure this is true - certainly for not Type 5 diesels.

Hornby 60 - 11 inches long over buffers , weighs 700g

The Bachmann 66 is pretty similar in terms of length and weight, and I'd expect the Bachmann 40 mentioned above to be in the same league as well. The Heljan 47's not far off either

Even the powered coach of my 2 car Bachmann Turbostar DMU scales in at 1lb (450g). This is the same mechanism as Bachmann use in the 158 and Voyager , so the worst load it faces is a 5 car Voyager - powered coach + 4

Bachmann's 20 is a mere 425g , but this is a narrow bonneted loco and the real things are only 1000hp

These are all common , widespread classes, so very much "bread and butter" models for a 4mm modern image modeller

Steam isn't my scene , but state of the art OO kettles aren't light either
I was thinking about steam as I don't really buy diesels. My Trix Big Boy is about a Kilo and ¾ (four pounds) whereas a Hornby Steam loco would be a quarter of that at the most. My BLI J1 is about a kilo too. The Hornby ones with loco drive are a lot better as there is more weight in the loco to keep it down but the two three year old ones still had tender drive and little weight in the loco to keep it on the tracks. The newer ones are definitely better. Bachmann ones tend to be better weight wise too. I haven't had any problem with Bachmann locos only Hornby but they do seem to be sorting this out.

The Hornby GNER 225 can't pull any more than five coaches on the level which is annoying as I have eight and it just sits there with it's wheels spinning out of control!

Spot on!

I faintly recall having an old loco that did not have wheels specifically designed for tyres but which nevertheless had a tyre or two on it. It was utter garbage and I think was either given away, lost or otherwise canned.

I am not fond of tyres, but I do have a bunch of newer locos that have properly designed wheels and tyres that have given no bother. I think some of my distaste might be psychological. If I didn't KNOW they were there, I might be more content.

Just to let you know the Marklin is to selling 200 world record locomotives cat.no 37434.

Email from marklin we newsletter.

Naturally "limits: World record Unikate starting from Sunday in the on-line Shop How much does one need strength, in order to move 48 tons a heavy region car 10 meters far? The answer gave it in February in Munich: Straight once 200 Maerklin locomotives created the task loosely and drove with the world record directly into the Guinness book. We immediately received inquiries from collecting tanks, which wanted to acquire or several of these course-strong models. To the special value accordingly we arranged however first a suitable package to it, which we offer now exclusively in the on-line Shop. Completely with a showcase, the strong unique pieces naturally go to a video DVD, special Beduckung and decoder programming and with authenticity certificate now to the start. Starting from Sunday, the record locomotives are to be seen 20 to May at 00 o'clock on the homepage of the Shops and ordered - however naturally only maximally 200 pieces! We would like to give the possibility to our Web news readers with this message of belonging to the first prospective customers and of securing themselves their piece of collecting tank in time. But you find in the Shop pictures and further descriptions of detail as well as a hour meter to you already before help not to miss the start of the action. Look thus more frequently after under

http://www.maerklinshop.de/index.php?sid=0...00b793.15354971

QUOTE (dwb @ 27 Feb 2007, 21:25) <{POST_SNAPBACK}>>So if the coach weighed 48 tons and there were 200 coaches, does this mean that each loco was pulling a quarter of a ton?
Not if the coach is on level ground. The weight of the coach will act in a line running at 90 degrees to the rail on which the coach rests. The locos pulling the coach have to overcome the rolling resistance of the coach along the rail. This is determined by the coefficient of friction between the wheel and the rail and that is where my memory of applied mathematics runs out..... but I'm sure there is at least one member who can pick up the baton and run with it. I for one would welcome a "refresher" on this.

David

I did this calculation recently because Roco had some H0 Taurus models (I can't remember how many but I think a few hundred) pulling a full size Taurus in much the same manner as Maerklin have done here except the Taurus is 86t, quite a bit heavier!!

The coefficient of friction mu for a steel wheel on a steel track is about 0.01 for the sort of wheels and track used here. So the resistive force of the coach is F = mu*R where R = M*g = weight of coach. That is F = 0.01*48000 = 480 N so each of the 200 model locomotives must provide 2.4 Newtons. Interestingly since the locomotives were in groups of four then the rear locomotive connected to the rope/wire would have a stress force of 9.6 N on its coupling and couplings are just bits of plastic! Obviously a tough bit of plastic unless they were in some way strengthened, or perhaps that is a reasonable amount comparable to a long rake of H0 wagons? The calculation for the locomotive's capabilities is a bit more complicated!

Goedel