Varying gauge length required

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Gscale99

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#1
Hey I need to design a train from scratch that can travel along 1.48 - 2.08 inches of rail width,
The train also has to climb a 45 degree slope.
I was thinking
- Extending the cone shape of the wheels to accommodate the change in rail width
- Having an axle that changes length with respect to the rail width
Any suggestions for this project in terms of ideas or wheel material?
Many thanks!
 
Greg Elmassian

Greg Elmassian

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#2
you want it to automatically adjust to a varying gauge?

are there any switches? it's easy for rolling stock if so, you use wheels with flanges on both sides, to follow the rail, one wheel slides on the axle.

locos are tougher... but can be done.. you are going to need a rack system, so locomotion will come from the rack gear, not the wheels.

Greg
 
dunnyrail

dunnyrail

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#3
Double Flanges Wheels with end stops and middle stope to keep to greatest and minimum Gauge. Was used in North Wales on Quarry Lines with 2ft Approx Gauge Wagons only.
 
Zerogee

Zerogee

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#4
For the 45 degree slope (assuming that's not a typo of course! ;)), you'll need either a rack-and-pinion system or a cable-hauled (funicular) one....?

A few more details about "what" and "why" for this project might elicit some more practical ideas, are you trying to replicate a particular very unusual prototype situation?

Jon.
 
Rhinochugger

Rhinochugger

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27 Oct 2009
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#5
1:1 trains do it in Spain - but not up a massive slope.

Check rails would help with wheels sliding along splined axles, but where you'd get the splined axles :think::think::think:
 
G

Gscale99

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#6
you want it to automatically adjust to a varying gauge?

are there any switches? it's easy for rolling stock if so, you use wheels with flanges on both sides, to follow the rail, one wheel slides on the axle.

locos are tougher... but can be done.. you are going to need a rack system, so locomotion will come from the rack gear, not the wheels.

Greg
So this is the track we will be tested on, the portion labelled "Damaged track" represents a slight increase in gauge length which then returns to normal gauge up the hill.
113751_99415d0a3426a12d0c6dd98a1e86b94c.png
 
G

Gscale99

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#7
For the 45 degree slope (assuming that's not a typo of course! ;)), you'll need either a rack-and-pinion system or a cable-hauled (funicular) one....?

A few more details about "what" and "why" for this project might elicit some more practical ideas, are you trying to replicate a particular very unusual prototype situation?

Jon.
Thanks for the info! So we basically have to build a fully autonomous train that has to complete the track seen in the picture posted. The two important considerations are the "damaged track" that slightly increase gauge length of the rail and the 45 degree incline.
Being autonomous aside, I am interested to know if standard G scale (plastic) wheels will be able to adapt to this increased gauge length and how they will climb the incline.
I was also thinking of having different gear ratios, one for high speed for the straight and one for high torque to climb the hill.
 
korm kormsen

korm kormsen

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#8
a 45 degree incline wins one foot of hight in one foot of length.
a 45 percent incline wins 5.4 inch in one foot of length.

the steepest, i was able to run largescale trains on was 8 percent/3.6 degree. (0.96 inch height in one foot length)
 
Greg Elmassian

Greg Elmassian

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#9
after all the helpful responses, can you tell us why and how you got this project? Is this a display layout or a design challenge? (asking again because you did not answer)

you ask about plastic wheels climbing this grade... read carefully: you will NOT be able to climb this grade powering the wheels, you will either need a rack system (look up rack railway) or tie a cable to it and pull it up. You will most likely be making custom wheels for the rolling stock, and I would recommend metal.

How many cars are you pulling up? Can they be 2 axle or do they need to be 4 axle?

Greg
 
G

Gscale99

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#10
after all the helpful responses, can you tell us why and how you got this project? Is this a display layout or a design challenge? (asking again because you did not answer)

you ask about plastic wheels climbing this grade... read carefully: you will NOT be able to climb this grade powering the wheels, you will either need a rack system (look up rack railway) or tie a cable to it and pull it up. You will most likely be making custom wheels for the rolling stock, and I would recommend metal.

How many cars are you pulling up? Can they be 2 axle or do they need to be 4 axle?

Greg
This is for a design challenge which doesnt permit the use of external methods to pull the train up the hill. The number of cars or axles is completely up to us.
Thank you.
 
G

Gscale99

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#11
This is for a design challenge which doesnt permit the use of external methods to pull the train up the hill. The number of cars or axles is completely up to us.
Thank you.
Would you recommend having an extended width wheel from lathing a block of steel or 3D printing an extended width wheel? As the aim is for greatest traction, cornering and hill climbing abilities.
 
trammayo

trammayo

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#12
Would you recommend having an extended width wheel from lathing a block of steel or 3D printing an extended width wheel? As the aim is for greatest traction, cornering and hill climbing abilities.
Well, following on from my PM, I would say it is quite a challenge! You could simply have longer axles and put two wheels on each end (i.e. face to face) - that would maintain the gauge of the good track.

As for traction without external aids, and having personally operated and maintained a funicular railway in the 12" to the foot world, I would say you have a very difficult job. Cable haulage (powered or self-acting), rack & pinion, or Fell Rail would be the real world answer.

Might I suggest a version of the Fell Rail? Instead of having the raised centre rail, use one of the running rails as that item. This all presupposes that you are running on LGB or similar track. It would be difficult to do that - on a horizontal plane you could have a sliding motor block/drive unit which could accommodate curves and gauge variation - but in the vertical plane I reckon it would be nigh impossible!
 
PhilP

PhilP

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#13
Forget two speeds. - Unless time to complete the course is taken into consideration.

Double-flanged wheels are a possibility.

Define 'no external methods'. - Could you have a length of 'cable' and attach to a drum on an axle? i assume autonomous rules this out??

If you have to rely on adhesion only, you will need rubber-tyred wheels, and overall weight (and it's distribution) will be important.
 
tac foley

tac foley

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#14
I'm not saying that what the OP wants to do is impossible, using physics as we understand them, Jim. Let's just say that without physically gripping the track from the sides, effectively clamping the loco to the rails, AND using cogs/racks, á la Fell System, it is 99% impossible. All the railways that have to make this kind of trip, like the Great Orme, San Fransisco, Lynmouth, Aberystwyth, CAT and so on, are cable-hauled.
 
Neil Robinson

Neil Robinson

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#15
I don't think a rack and pinion system should be classified as an external aid.
Surely it's no more external than conventional driving wheels and plain track.
 
Zerogee

Zerogee

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#16
I don't think a rack and pinion system should be classified as an external aid.
Surely it's no more external than conventional driving wheels and plain track.
I would agree, Neil, though as a rack and pinion system requires the rack itself to be fixed to the track, it might be outside the scope of the "challenge" rules..... I'd be intrigued to know more about what this is for - an educational or tech challenge, a competition of some sort, maybe even some form of Reality TV thing....?

If a rack rail is banned, then I really think the gradient section is going to be nigh-impossible - the variable-gauge bit is likely to be doddle in comparison.... ;)

Jon.
 
korm kormsen

korm kormsen

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#17
i strongly suggest, that you ask the people, who formulated this challenge, if they are sure, that they mean 45 DEGREE.
a 45 degree = 100 percent = one in one inclination is just the point, where gravity beats friction forces.
chutes for bulk freight (grain, sand, coal or similar) are made with 45 degree, to guarantee free downward movememt of the freight.

you could overcome different gauges with tecnical measures, but you could never overcome the law of gravity, save by levitation.
 
JimmyB

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#18
If the wheels had flanges on both sides to "grip the rail" and the wheels themselves were on splines that allowed the wheels to move in and out, but still be powered, with enough weight may work.
 
tac foley

tac foley

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#19
In my experience, varying the gauge makes the train fall off. I think that we are suffering from semantics here, and don't believe that the OP actually means a track gauge that varies from one point to another.

I strongly support Kormsen's comments in that regard.

Given the limits of physics, and knowing something about material adhesion piling angles from my geology study days, I'd say that the whole thing, as described by the OP, is an exercise in futility. Just look and see how many natural slopes of loose, non-adherent materials [slate, shingle, broken rock et al] exist that are more than 45 degrees. I'll be very happy to be proven wrong.

No harm in trying, though.................
 
tac foley

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#20
If the wheels had flanges on both sides to "grip the rail" and the wheels themselves were on splines that allowed the wheels to move in and out, but still be powered, with enough weight may work.
Jimmy, that, in a nutshell, is the basis for the Fell system I mentioned above and noted previously by another poster.