Subject:
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How to pull a long train (Was: Re: End of 9V Trains protest layout idea)
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Newsgroups:
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lugnet.trains
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Date:
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Wed, 24 Oct 2007 10:41:39 GMT
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Viewed:
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7410 times
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In lugnet.trains, Reinhard "Ben" Beneke wrote:
> In lugnet.trains, Bob Parker wrote:
> > Does the fixed two-axle type freight car offer more resistance around curves
> > compared to modern swiveling trucks like I imagine it would? Or would it
> > depend on the length of the car itself compared to the curve radius?
>
> Good question - depending on my former tests, I would guess, that short
> 4-wheel waggons (like the lightweight barrel waggon from set 2126) with not
> more than 6 studs distance from wheel block to wheel block offer the lower
> running resistance. Any car with bogies has the doubled amount of wheel sets
> and this ends in higher running resistance on straights.
>
> So if you want to make up the train with most cars, use short 4 wheel ones.
> (disadvantage in curves: the wheels biting the curve / advantage: only 2
> wheel sets per 20 studs total length).
>
> If you want to have the longest possible train (in absolute length), try to
> use cars like the <http://guide.lugnet.com/set/4543 Set 4543> with low weight
> and 28-studs baseplate. (advantage is the wheels not biting the curve /
> disadvantage on straights: 4 wheel sets per 32 studs total length => still
> more wheels per length).
>
> Both types have their benefits, one on straights (and this is the longer part
> of the train), one in curved section (this is the most critical area, where
> magnets might tear apart).
The running resistance is a complex issue. Its main factors are: weight, speed,
distance between axles, and track type (straight/curve). On the real life
trains, suspension is also an important factor.
On a straight track, the movement of a train is not straight, but a kind of
zick-zack, because the gauge of the wheels is always narrower than the track
gauge (to reduce friction) and the wheelpairs can move a bit to the sides. Every
"zick" or "zack" is a short time of friction between the wheel flange and the
rail = the wheel bites the rail for a while.
To reduce the zick-zack, one must add weight, or move the wheelsets further
apart, or reduce speed. It's not true that a short light car would run smoothly
on straight track. I've tested it with the old white bogies (
http://www.peeron.com/inv/parts/824 ) with only wheels and couplings attached.
These are probably the ligtest&shortest LEGO traincars :-)
The bogie cars are not the same as very short cars coupled together, because the
car base adds weight and friction which reduce the zick-zack movement.
As for the curves, there must exist an axle distance which eliminates the
zick-zack movement but does not cause additional friction (bite). Bogie cars
have disadvantage in the friction between bogies and car base.
>
> Another question is: if you have a mixed train - where should the bogie cars
> be placed? In the front or in the rear?
>
> In my tests the rear seemed to show slight advantages, but I cannot explain
> why.
>
> Are there rules from real life trains, how to mix two different kind of
> waggons?
>
> Leg Godt!
> Ben
I don't think there are any rules for that, as the cars are coupled according to
their destinations. Any kind of sorting bogie cars would need too much extra
shunting.
A possible explanation for your test results is that the cars are pulled on the
bogie (unlike real life, where are couplings on the car base). The more load
they pull, the more they are likely to zick-zack and the more friction appears
between flanges and rails.
Regards,
Martin
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Message has 1 Reply:
Message is in Reply To:
 | | Re: End of 9V Trains protest layout idea
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| (...) Good question - depending on my former tests, I would guess, that short 4-wheel waggons (like the lightweight barrel waggon from set 2126) with not more than 6 studs distance from wheel block to wheel block offer the lower running resistance. (...) (17 years ago, 24-Oct-07, to lugnet.trains, FTX)
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