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Thread: High Balling steam, loco restoration

  1. #11
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    The forces must be terrific, which is probably why nobody has bothered to try and beat the speed record of 126mph achieved back in 1938 by Mallard.

  2. #12
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    Boy those Lionel train sets look more realistic every year.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

  3. #13
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    Quote Originally Posted by Tungsten dipper View Post
    As a rule of thumb, a steam locomotive can go as fast as the diameter of its drivers. The 844 has 84" drivers and I've ridden behind her doing well over 90 miles an hour!
    Just did some quick math:

    84" drivers at 90 mph works out to 360 rpm. There are 4 power strokes per revolution, so that makes 1440 power strokes per minute, = 24 strokes per second, with each stroke lasting 0.042 seconds.

    It doesn't seem like much time for each little wad of steam to get in there and do any work before heading out the stack..

  4. #14
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    Quote Originally Posted by john hobdeclipe View Post
    Just did some quick math:

    84" drivers at 90 mph works out to 360 rpm. There are 4 power strokes per revolution, so that makes 1440 power strokes per minute, = 24 strokes per second, with each stroke lasting 0.042 seconds.

    It doesn't seem like much time for each little wad of steam to get in there and do any work before heading out the stack..
    Which is why you pull back on the Johnson bar which cuts off the admission of steam to smaller bursts the faster you go.

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  5. #15
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    Quote Originally Posted by RB211 View Post
    Which is why you pull back on the Johnson bar which cuts off the admission of steam to smaller bursts the faster you go.

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    Dang RB, sounds like you have been learning to fly one of those too !

  6. #16
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    Quote Originally Posted by larry_g View Post
    On the cylinder part of the timing of the steam inlet is that the intake valve opens a bit before TDC so that the steam pressure assists in stopping the piston so that it can reverse for the next stroke. All that helps to smooth out the motion.
    Larry,
    I have read (on some steam engines anyway) that they close the exhaust before it reaches the end of the stroke so the remaining steam is compressed and brought back up to boiler pressure. Just what they do on 844 I am not sure, I need to do some reading. I think uniflow engines do this, not sure about locomotives though.

  7. #17
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    Quote Originally Posted by Sparky_NY View Post
    Dang RB, sounds like you have been learning to fly one of those too !
    Think steam locomotives were my first love in life. When I was out of Aviation, I had interviewed at Union Pacific. Obviously didn't get the job. Was also taking classes to become a respiratory therapist, and doing machine work, electronics, and 3D cad for a friend. That was the hardest time in my life. Needless to say, aviation came back and saved the day.

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  8. #18
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    Quote Originally Posted by RB211 View Post
    Think steam locomotives were my first love in life. When I was out of Aviation, I had interviewed at Union Pacific. Obviously didn't get the job. Was also taking classes to become a respiratory therapist, and doing machine work, electronics, and 3D cad for a friend. That was the hardest time in my life. Needless to say, aviation came back and saved the day.

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    The air conditioning works better in the dash 400 than those steam locomotives too!

  9. #19
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    Quote Originally Posted by Sparky_NY View Post
    The air conditioning works better in the dash 400 than those steam locomotives too!
    The two cab rides I did, don't remember the heat being bad. What I really remember is how you felt everything running, the sounds, etc. Everytime the air compressor did a stroke, it reverberated throughout engine frame right into your seat. When the engineer notched up a gear before being at the right speed, how the running gear started to clang and the engine shook forward and back.
    I'd imagine however that riding in the cab in the North East during a cold fall day would be quite an enjoyable experience.

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  10. #20
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    Very interesting about admitting steam to the end toward which the piston was moving to cushion it and slow it down before it reversed. I know of something similar. I spent a couple of years designing high production sawmill machinery, and that brought me into contact with something called a "Gardner Gunshot" carriage. Instead of a winch and cables to move the carriage with the log on it thru the saw, a "Gardner Gunshot" was a large bore, telescoping steam cylinder which drove the carriage. The log and carriage moved very, very fast thru the main saw--so fast that the operator had to deadhead the steam before the carriage reached the end of its travel, in both directions. This required a very skilled sawyer. The sawyer at A.J.Milne on lake Temiskaming made so much money, and wanted more, that the company fired him and hired someone else to do the job. After the second time he blew the entire carriage out thru the end of the mill into the lake, the old sawyer was hired back at double his previous wages. I was there in the mill about two weeks after they had hired the old sawyer back.--Sure enough, the entire end of the mill, directly in line with the carriage was all new lumber.
    Last edited by brian Rupnow; 08-17-2019 at 08:34 PM.
    Brian Rupnow

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