Varying gauge length required

PhilP

PhilP

G Scale, 7/8th's, Electronics
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#21
Philosophically:
We need to know more.. - It could well be the 'challenge' is designed to fail, as learning to accept / realise a goal is unattainable is a valid lesson in life. :nerd:

Depending on the materials used for the track 'bed', could not magnetic attraction be used for added 'grip'? :think:

Oh, do 'we' get merits for this? ;):nod::giggle::giggle:
 
tac foley

tac foley

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#22
Philosophically:
We need to know more.. - It could well be the 'challenge' is designed to fail, as learning to accept / realise a goal is unattainable is a valid lesson in life. :nerd:
Like I'm beginning to fail to retain my erstwhile interest in this thread.............
 
Greg Elmassian

Greg Elmassian

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#23
Well, if the greatest ability to corner and strongest grades, then emulate the roller coaster system where the "track" is tubular, and you have rollers on the top, bottom, and sides of the tube... that will take ANY grade and will even work upside down.


You need to have more constraints...

So far, no external means, so no external cables and pulleys.
you will need a rack gear between the rails, so the "locomotive" can pull itself (no external means)
you have not delineated any restrictions on the "track"... must it be rails of metal on ties, or can you get creative like above.

If you have the loco merely sitting on the rails, and you want steepest grades and tightest corners, then "narrow gauge" with all the rolling stock designed for a low center of gravity.

But you said in another post it is 45 degrees... so that is doable...

Greg
 
tac foley

tac foley

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#24
'kaaaaaaaaay. Let's try a little experiment. Set up a piece of track at 45 degrees to the horizontal. Place a four-wheel wagon on it, and observe that the wagon 'wants' to rotate around the lower set of wheels due to weight transfer.

Now do the same thing with a locomotive - any locomotive - but preferably one that has just four wheels.

Oh, and don't let go.
 
PhilP

PhilP

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#25
But Tac we are not talking about a 'wagon' or a 'loco' that we already have..
We are talking about a purpose-built 'autonomous vehicle'. - So to work, would need a low centre-of-gravity, amongst other things.
 
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ColinK

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#26
While it would not be enough on its own to get the train up the hill, a large scale version of DCC Concepts Powerbase might help.
 
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playmofire

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#28
Maybe there are the seeds of a solution here.
 

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tac foley

tac foley

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#29
But Tac we are not talking about a 'wagon' or a 'loco' that we already have..
We are talking about a purpose-built 'autonomous vehicle'. - So to work, would need a low centre-of-gravity, amongst other things.

The OP talks about a train - a train is a locomotive AND wagons, right? My comment was aimed at getting the idea of the forces that act on any wheeled vehicle at sharp angles, so that you can see the near impossibility of the project without some serious engineering happening.
 
Rhinochugger

Rhinochugger

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#30
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.................
Hang on, this is a challenge ..................it may not just be about railways as we know them.

What if the wheels were made of something other than metal? say rubber.

I agree that probably even then, 45 degrees would be pretty ambitious.

Remember, the OP originally thought about cones for tackling the gauge change ;);)

Rubber cones :think::think::think::think::think:
 
daveyb

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#31
jet power,,,,,,, or even prop powered to get up the hill,, its all about power!!
 
Paul2727

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#32
Assuming that the builder is permitted under the rules of the competition to build both their own train and track, then Perhaps rollercoaster engineering may be worth exploring. After all, they climb steep slopes. (Including vertical at two points of a vertical loop.) And rarely come off the track. (Thankfully.)
Then vector in a bit of solid fuel rocket sled technology, triggered at the base of the incline. Just lock the health and safety guy in a convenient cupboard and let her rip.:devil::devil::devil:
(Please do not try this at home! ;) )
 
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phils2um

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#33
My 2 cents - we need to grip a rail to overcome the gradient. I suggest a "drive" side and none "none drive" side. The drive side rail is gripped by two almost vertically mounted, motor driven, counter rotating rubber rollers that pinch the rail to give propulsion. The rubber rollers will be slightly angled so a small "down force" is created to keep the vehicle on the rails. The vehicle rides on two wheel axels with dual flange wheels on the drive side and extra wide blind wheels on the none drive side to account for the varying gauge. I think this would be doable for the specified rail gauge but is not scalable. The coefficient of friction between rubber and steel or brass does not increase with size. The vehicle mass and thus the force to overcome the grade will tend to increase with the cube of the volume (scale) while the propulsive force is a linear function of the rubber-rail contact patch.

Phil S.

Edit 1. Just went back to look at the OP. Is the varying "rail width" an change in rail gauge in which case we're talking roughly 1 gauge (oh no! :(:(:( -here we go again with the gauge/scale discussion) or a change in the rail head width? If it is indeed a change in rail head width then we're talking about actual size rails/trains and I doubt my solution is practicable for the reason cited in my original 2 cents.
 
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Peter Peter

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#34
Interesting discussion, especially for a novice like me!

Suspect the plan provided to contestants may be the only interaction with the track until the 'train'/'vehicle' turns up to be placed upon it, this ruling out track modifications such as a rack.

Gscale99 - when the time comes, I and perhaps others would enjoy you reporting back on your developed solution, how you got on and what other solutions were offered. (Photos are always good!)
 
Northsider

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#35
If the challenge is to build a locomotive from scratch, and assuming the track is unballasted, couldn't the sleepers be used as the rack, with a powered cog of the correct pitch being mounted centrally on the chassis?
 
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ColinK

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#36
Just a thought, why not have large diameter wheels at the downhill end of the rail vehicle, small diameter at the uphill end, might help stabilise it.
 
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Paradise

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#37
Sounds like a committee designing a racehorse. :think:

 
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David1226

David1226

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#38
Thread drift here, seeing the above picture. My son-in-law works for an organisation that issues accreditation to forensic science laboratories. One of the labs that he has to visit is in Abu Dhabi which does dope testing on racing camels. As an aside, in Saudi Arabia they do not like The Flintstones, but Abu Dhabi do........

David
 
Greg Elmassian

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#39
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.

So a week later and no reply. :wasntme:

You need a rack system (see rack locomotive)
Are you really building this or designing as you said earlier?
From your quote above... traction of the wheels is not an issue, since you CANNOT use wheels to drive yourself up a 45 degree slope.
You will be going slow, so the 2 rails will be at the same height, so cornering is not an issue, unless you mean the curvature of the track, and you won't be able to make that super sharp since you have a gear between the rails.
Hill climbing will only be possible with gears, and if you are using rails, then the gear needs be be somewhere else, only logically between the rails.

Greg
 
JimmyB

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#40
Watched Tarrent in Spain the other day, and the new high speed train does not have axles, apparently to have more stability on uneven track, however later in the programme, it showed the train being re-gauged from standard to Iberian at 15 kph, so this is one way forward for the varying gauges!!