Here I go again.....

Re: Here I go again.....

Postby ConducTTor » Fri Jan 10, 2014 4:02 pm

Juup wrote:b) try to have express trains passing through a station (without stopping) do so without using the curved part of a turnout … they should be moving straight through any turnouts or else they will have to slow down quite a lot. That might be a challenge for ConducTTor to achieve … but there is always ‘compromise with awareness’ :)


The above is correct. It's a big reason for the various geometry/track plan compromises I originally had. I ultimately decided to let this one thing be wrong - it allowed me to fix several others.
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Re: Here I go again.....

Postby krokodil » Fri Jan 10, 2014 6:06 pm

Hi Juup

The model speed is a quite complex issue. Even the correct rate is too much for layouts, because of longitudional distortions. The distances on layouts are never in correct scale. While a typical trains passes a station in every 3-10 kms, our model train passes a station every 2-5 meters ( in TT) what would be in origin just about nothing (240-600 m is less than a station track!). This means there is a longitudional distortion!
Some modelers speed up the time to compensate the distortion, or slow down the trains. ( on the novadays very popular huge modul layouts).

Forget the superelevation on the modellayout. The modeltrains are never so fast, that you need to compensate them against the centrifugal forces. On the other side because of huge frictions on of the cars they have a tendency to fall into the curve. With superelevation this tendency will be higher.
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Re: Here I go again.....

Postby j p » Fri Jan 10, 2014 6:42 pm

krokodil wrote:Hi Juup

The model speed is a quite complex issue. Even the correct rate is too much for layouts, because of longitudional distortions. The distances on layouts are never in correct scale. While a typical trains passes a station in every 3-10 kms, our model train passes a station every 2-5 meters ( in TT) what would be in origin just about nothing (240-600 m is less than a station track!). This means there is a longitudional distortion!
Some modelers speed up the time to compensate the distortion, or slow down the trains. ( on the novadays very popular huge modul layouts).

Forget the superelevation on the modellayout. The modeltrains are never so fast, that you need to compensate them against the centrifugal forces. On the other side because of huge frictions on of the cars they have a tendency to fall into the curve. With superelevation this tendency will be higher.


krokodil, you need to replace the trucks (or bearings and wheelsets) on your cars if your trains fall into the curve.
The superelevation was for explanation why the speed on the turnout is slower than on the track. It is not needed on the model with European flanges unless your train runs too fast. But it looks good!
You'd be surprised, but the laws of physics apply also to the model train. You can try to run a 4-6-6-4 Challenger at full speed through a sharp curve. It would do exactly the same as the real train...
It is a heavy model made of metal, with its center of gravity relatively high. It can also pull 100 old HP cars or maybe 200 new cars, less if the magnet in its motor is getting weak.
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Re: Here I go again.....

Postby ctxmf74 » Fri Jan 10, 2014 7:20 pm

"the laws of physics apply also to the model train."

Most model train layout curves are so sharp that they would not be superelevated in the real world and they'd be run around at walking speed. I saw the SP 4449 trying to go around the wye at Watsonville Ca. many years ago and they had to grease the rails and walk it around with a diesel pushing it. Don't know what the radius of that track was but I'm sure it was much larger than most layouts would have......DaveB
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Re: Here I go again.....

Postby ConducTTor » Fri Jan 10, 2014 10:17 pm

krokodil wrote:On the other side because of huge frictions on of the cars they have a tendency to fall into the curve. With superelevation this tendency will be higher.


This is very interesting. I *thought* superelevation would help the cars around the curve.
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Re: Here I go again.....

Postby ctxmf74 » Sat Jan 11, 2014 12:48 am

" This is very interesting. I *thought* superelevation would help the cars around the curve."

If they are moving fast enough it helps. If they are going too slow for centrifugal force to lean them to the outside of the curve then they will tilt to the inside and become less stable if a loco is pulling on a long train.( since the couplers are above the rail head there is a certain amount of leverage working to turn the car over to the inside of the curve,and the tilt assists it) ...DaveB
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Re: Here I go again.....

Postby ConducTTor » Sat Jan 11, 2014 1:03 am

^^^ makes sense
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Re: Here I go again.....

Postby LVG1 » Sat Jan 11, 2014 4:33 am

Juup wrote:Modelling DB or other continental railroads the speed limit for station turnouts may usefully be 40km/h (for a NA layout 20-35mph), and outside of stations 60-100km/h depending on the kind of line (NA layout 50mph).


I'm afraid, this gradation is quite a bit simple and not too realistic.
If you want to find out which turnout speed is the best for you, you'll need a sense of "history" of your layout.
For long time 40 km/h-turnouts were the standard. There was hardly anything else.
Eventually around World War II, 60 km/h-turnouts came up. Initially, they were only used on main lines. But eventually, they became the new standard.
100 km/h-turnouts emerged in the 1960s or 1970s or so.
So you'll have to determine the era to which your trackage dates back.

Roughly, you can use following orientation.
  • Pure switching areas: 40 km/h-turnouts are still standard because the general speed limit for switching (in Germany) is 25 km/h (16 mph) with cars and 40 km/h without cars, respectively, and "faster" turnouts would unnecessarily cost more.
  • Train stations: 40 km/h- and 60 km/h-turnouts are about equally common. Which type is used, depends on the state of maintenance of your station's trackwork and on geographical circumstances. Initially all turnouts were limited to 40 km/h. Those turnouts, which were simply replaced when worn out, are still 40 km/h-turnouts. But where the entire track plan has been reworked (and usually simplified on that occasion) 60 km/h-turnouts will have been used. Only at locations suffering from extremely limited space (and often in dead end stations because there all incoming trains are generally restricted to 40 km/h [in Germany]) you'll find one or another 40 km/h-turnout in new track plans, too.
  • Outside stations: Nowadays, 60 km/h-turnouts are standard. 40 km/h-turnouts have become kind of rarity; you'll mainly find them on branch lines.
  • 100 km/h-turnouts: They are (almost) only used, where one main line diverges from another one. You'll find them mainly outside stations, but also in small and medium size stations where many (passenger) trains don't stop. Their number rises with the date.
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Re: Here I go again.....

Postby krokodil » Sat Jan 11, 2014 4:40 am

ConducTTor wrote:^^^ makes sense


That is correct. The model trains are slower, have much higher frictions ( even with best wheels, just think about the model couplers!), the curves are tighter and the centre of gravity is much higher, so the initial conditions are completely different form the real trains, therefore the superelevation has in model trains just bad effects. Some modelers in the past even recommended negative superelevation for a troublefree modeltrain operation. ( outer rail is lower). I do not think that we should follow today their recomendation, but we definitively do not need superelevation on layouts.
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Re: Here I go again.....

Postby krokodil » Sat Jan 11, 2014 5:18 am

j p wrote:You'd be surprised, but the laws of physics apply also to the model train. You can try to run a 4-6-6-4 Challenger at full speed through a sharp curve. It would do exactly the same as the real train...
It is a heavy model made of metal, with its center of gravity relatively high. It can also pull 100 old HP cars or maybe 200 new cars, less if the magnet in its motor is getting weak.


I know, i built myself over 30 sctratch built locomotives and I also have several US diecast boiler machines ( in H0 from Browser, MDC etc). This is exactly the problem, if they are fast in the curves the tend to tilt out ( but this means your speed is unreallistically fast, unfortunately in the past the speed of models was far to high).
If you put superelevetion into your tracks, two things may happen.
If you stop your challenger it will fall into the circle and the long train pulled by the challenger will have the same problem. Ie you must pass the superelevated curve with a minimum speed to avoid these effects. What about the slower trains in such curves?
Such things are extremely critical especially for steam locomotives with high heavy boilers ( bad construction decision). The frame of such machines is empty ( because everybody wants to see the wheel axles etc.). To gain weight = traction they put ballast into the boiler a shift the center of gravity very high. Combined with high speed ( bad gearing or fast motor) the disaster is on wheels :-) ( i expereinced this unfortunately from my own construction as well. :shifty: :wtf: ).
Last edited by krokodil on Sat Jan 11, 2014 12:39 pm, edited 2 times in total.
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