Railroad Bicycle 1

[AlpineAce]

Hey guys,
Im contemplating making a railroad bike.
What I've found on the net, looks pretty terrible.

My thoughts are to make a bike that performs better than my high end road bike, mainly though lowering the rolling resistance, since I'd eliminate the tires, and rolling on a extremly hard and smooth surface.

What I have seen online used an out rigger and guides to hold the front wheel steady, which almost negates any advantages.


So I found the cross section of a rail road rail, along with some specs:

and the heads vary between 2-1/4" to 2-3/4" in width


So I'm thinking why cant I just make a rim that is either V shaped or simply curved, and it will sit on the rail and self align?
Thus I will have minimal contact points, and lowest rolling resistance? and thats it?


Also should this work, what kind of increase in speed?decrease in resistance or energy output might, I expect to see?

I'm working on it!

 

[red92s]

If you want a rail-capable bike because you can (maybe) go places a normal bike can't, that's one thing. But it sounds more like you are just trying to make a more efficient bike. What's the point of eliminating the rolling resistance in search of efficiency, only to add additional (rotational) weight and maybe a trailer to carry roadworthy wheels and tires? If you are seeking efficient return on your energy expenditures, and not just a likely-very-illegal adventure, I think you will be poorly disappointed. A modern, lightweight, properly geared road bike is a pretty freaking efficient machine. I have a hard time seeing how adding 25 pounds is going to make things better.

 

[GregLocock]

Dissapointing to see that nobody has tried to estimate the increase in speed by eliminating the rolling resistance from the tires.

Roughly speaking Crr best race tire 0.0025 Crr typical railway wheel 0.0010 to 0.0024

Now imagine what the Crr of an inverted V section on the rail is likely to be, I'd guess the upper end of the range for normal railway wheels.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[moon161]

Rolling resistance of good HP tire << gravity and drag.

 

[tr1ntx]

I thought about pedal rail quad-cycle several years ago. I often drove on a rural highway and there was a rarely used track that ran beside parts of it. The rail line veered off through much more interesting scenery, ran along a river and through some big ranches, places the general public couldn't access.

My thought / scheme / notion at the time was to make polyurethane wheels shaped sort of like the railcar wheel MintJulep shows, though narrower than the top of the rail and with less of a flange. I was thinking along the lines of making it very light and easy to throw off the tracks and into the bushes if I did hear a train coming. They only seemed to run maybe 3 times a week on that line, "seemed" being the operative word. I just wanted to get outdoor cycling leg exercise without dodging traffic and to get out into the countryside of those remote stretches of rail.

I was thinking of arch frames with a webbing seat suspended on bungee cords for shock absorption, a "recumbent bike" type pedaling position where you're actually sitting down hung below the frame.

 

[red92s]

Bit more information on railbiking below. Guy even sells wheels and plans for building pedal or motor powered carts:

http://www.railriders.net/railbiking.html

 

[AlpineAce]

Thank you all.

 

[prex]

Your example is a demonstration of the impossibility of your intent: the acrobat can ride on a bicycle with fixed front wheel only owing to the long bar he's in his hands. This is the device that replaces the steering effect in maintaining equilibrium at low speed. At higher speeds the gyroscopic effect helps, but is not sufficient alone: steering is still required to recover the right path when something drives you (the front wheel) out of it, e.g. a pebble or a small hole or a side slope.
Your idea of using a standard bicycle without tires on a long tube is the right one to test.

prex
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[red92s]

here is a summary of railroad tresspass laws in every state published by the FRA (Federal Railroad Administration), though it may be out of date. Things have goten worse post-9/11. Every train has a radio, and every railroad maintains it's own police force.

http://www.fra.dot.gov/downloads/safety/cross_chp9.pdf

 

[chicopee]

I am with Berskshire on this outrigger concept. A motorized bike would make more sense.

 

[chicopee]

Of all the bicycles shown above picture # ATT0001515 may be the grand daddy of them all. See attachment

 

[berkshire]

chicopee,
The scary thing about a picture like that, is that the sweet young thing sitting on the bike, is probabaly old enough to be your great grandmother.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[chicopee]

Don't forget Berkshire, these great grand old folks were also smart and you can see that by their machines they developed as you have seen in the rest of the pack of my attachment. Much of what we know today is due to their intelligence.

 

[berkshire]

Yea,
I was thinking about that.
I was looking at the picture of the Amphicar on a stretch of the river avon where I used to sail 40 years ago (ATT000999).
That picture does not look so old, or is it me?
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[RossABQ]

That bicycle the gal is on is what was referred to as an Irish Mail when I was young. The handlebars cycle back-and-forth to drive a crankshaft on the rear wheel.

There are many abandoned rail lines in the USA, some go thru very nice country, too. But they are likely in such poor shape that rail spacing is compromised, the roadbed choked with weeds and trees, etc.

But Moon161 hit the nail on the head, wind resistance is the dominant force to overcome in cycling. ASME magazine had an article on this about 20 years ago.

 

[JStephen]

Most lines, when truly abandoned, have the rails pulled up for scrap, they're worth money.

A standard road bike has VERY low rolling resistance- you're on skinny little tires with 120 psi or so. If you eliminated ALL the rolling resistance, it wouldn't be that much different. And if you had to put a metal wheel 3" wide on there to say on the rail, the wind drag and weight would offset any gains in rolling efficiency.

 

[SnTMan]

There is one factor in favor which I have not seen mentioned as yet:

Rail lines never climb very steeply. Or descend.

Regards,

Mike

 

[JStephen]

Mike, that's a mark against the idea, not in favor of it.

 

[RFreund]

Its been mentioned a few times that the rolling resistance is very low for thin tires and there would not be much improvement on a rail, but how about the small bumps that cause a slight change in momentum. It is common advice to keep tire pressure limited to 120 psi so that the tire can deform over small bumps as the resistance due to change in momentum is greater than the rolling resistance. Would there be a noticeable improvement here?

However I like this idea. I was/am more heavier rider/racer more of a classics/criterium rider and like the idea of hammering down a perfectly smooth track. Only problem is that the tracks are too busy where I live!

EIT

http://www.HowToEngineer.com