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Thread: Calling Coal Dragger

  1. #1
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    Calling Coal Dragger

    A guy I know asked me if I believed the earth was round or flat. Being clever I answered neither, it is a sphere.

    His evidence was that rail track rails aren't arched - I hope he was just being a smartass.

    Anyways, that got me to thinking, how do the railroads start a grade - is it just a minor deflection at each joint or something else?

    What about continuous rail?

    Thanks!
    Patriotism means to stand by the country. It does not mean to stand by the President... - Theodore Roosevelt, Lincoln and Free Speech, Metropolitan Magazine, Volume 47, Number 6, May 1918.

    Every Communist must grasp the truth. Political power grows out of the barrel of a gun. Our principle is that the Party commands the gun, and the gun must never be allowed to command the Party Mao Zedong, 6 November, 1938 - speech to the Communist Patry of China's sixth Central Committee

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    If you want to be pedantic and difficult, the Earth is actually an oblate spheroid.

    https://gisgeography.com/ellipsoid-o...pheroid-earth/

    Not that I would ever be difficult.

    Not Coal Dragger but the acceptable slopes for railroad tracks are very minor, no more than a few %, and steel track is more flexible than you might think in the lengths they use. I suspect the joints are just standard 90/90 degree joints and the flexibility of the track accommodates the minor slope. Guess I'll find out if I'm right as others post.

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    Quote Originally Posted by 26 Inf View Post
    A guy I know asked me if I believed the earth was round or flat. Being clever I answered neither, it is a sphere.

    His evidence was that rail track rails aren't arched - I hope he was just being a smartass.

    Anyways, that got me to thinking, how do the railroads start a grade - is it just a minor deflection at each joint or something else?

    What about continuous rail?

    Thanks!
    The rail is actually quite flexible, the rail will deflect when locomotives and cars pass over, and that deflection takes place in the strongest most rigid cross section of the rail (vertical), the higher the speed or tonnage (or both) the more the rail will deflect under the wheels passing over. You can watch it in real time.

    So with that understanding it should come as no surprise that the horizontal cross section is even more flexible, easily conforming to the curves typically in place on most any main line, siding, yard, or industrial tracks you can find. As for grades anything much over 1% is pretty much considered mountain grade, while not that steep by automobile standards it’s plenty steep when you’re operating at less than 1hp/ton. Again the elevation changes even in undulating terrain are never severe enough to not be easily accommodated by the flexibility of the rail.

    Also keep in mind ribbon rail (continuous rail) comes off in 1/4 mile long sections, they are usually laid out months to a year in advance to “season” and let the steel acclimate to the temperature changes in the area it will be installed. They want it to contract, and expand for a few months at a minimum so it is stress relieved for the area. So they pull it off the specialized unit train and lay it on the right of way next to the tracks, on the ballast. Not being secured to any ties they conform to the larger contours of the ground like a noodle.

    This is a long winded way to explain to you that your friend is correct that the rail is not made with an arch in it, but incorrect in his reasoning because the rail is not rigid enough to stay perfectly strait without support underneath it that is also perfectly strait and level. The rail bends, by design. Your friend is not good at critical thinking, or logic.

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    Quote Originally Posted by Coal Dragger View Post
    Your friend is not good at critical thinking, or logic.
    Thanks for that explanation.

    I've actually been on the locomotive simulator that, I believe, BNSF has at Olathe/Overland Park, Kansas.

    Quite an experience to watch the engineer keep the train dead on speed as the train went up and down the steepest grades on the line with the simulator jarring as the train following bumped into slack on the downgrade and took out slack on the upgrade.

    My use-of-force simulators paled by comparison.

    My acquaintance, we aren't to friend status yet, was just being obtuse, he's actually very bright, retired LAFD and DSS Farsi translator.
    Last edited by 26 Inf; 10-23-19 at 14:39.
    Patriotism means to stand by the country. It does not mean to stand by the President... - Theodore Roosevelt, Lincoln and Free Speech, Metropolitan Magazine, Volume 47, Number 6, May 1918.

    Every Communist must grasp the truth. Political power grows out of the barrel of a gun. Our principle is that the Party commands the gun, and the gun must never be allowed to command the Party Mao Zedong, 6 November, 1938 - speech to the Communist Patry of China's sixth Central Committee

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    Ah arguing for arguments sake. Sounds like my kind of a-hole!

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    I'll tell you that the most difficult class I took when I was still training to be a land surveyor was Geodetic Computations. Not only is the world an oblate spheroid, it also has spots that are higher and lower than the average that end up being anomalies in the WGS84 datum for navigation.

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    Quote Originally Posted by 26 Inf View Post
    A guy I know asked me if I believed the earth was round or flat. Being clever I answered neither, it is a sphere.

    His evidence was that rail track rails aren't arched - I hope he was just being a smartass.

    Anyways, that got me to thinking, how do the railroads start a grade - is it just a minor deflection at each joint or something else?

    What about continuous rail?

    Thanks!
    Think of a series of straight lines that on average equal a curve. Over short lengths you can pretend the earth is flat at longer length you have to account for curvature.

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    like anything else rail can bend. Go to a train track and watch closely as a train passes over it. You will see it bend up and down as the axels go over it. When we transition from flat to a grade its almost like a ramp.

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    I was in Italy at a train station and my buddy decided to put a coin on the tracks to flatten it. The train was at a walking pace and I was surprised that the train actually seemed to lift as it crushed the coin. The engineer was there, half out the window and as the engine clunked over the coin he shot us a crusty look.
    The Second Amendment ACKNOWLEDGES our right to own and bear arms that are in common use that can be used for lawful purposes. The arms can be restricted ONLY if subject to historical analogue from the founding era or is dangerous (unsafe) AND unusual.

    It's that simple.

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    Railroad transitions from level track to a grade are done in the subgrade using spiral easements. This is also how track goes from a tangent to a curve. Its gradual and infinite from the point where the curvature (horizontal or vertical) starts transitioning to tangent or to level track. I am not a math person when it comes to building railroads, so the mathematics involved in calculating the spiral easement is not something I can provide a formula for.
    Last edited by nightchief; 10-24-19 at 13:08.

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