Chasing Big Boy No. 4014 in Longview, TX

Under its own steam…
Just a whistle stop. We’re hoping to get a tour tomorrow…

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I have several friends that are chasing 4014 around the southwest. Good luck on getting that tour!

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Andrew (jast) this is for you!

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After watching it chugging across country…


(Can’t find pics just this second, but believe you me, that horn can punch a hole in your chest, and t’is a majestic sight at stride!)
we made it to its overnight resting yard in Marshall just in time to watch it roll in…

Got up close & personal this AM…

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Some quick specs they had on display

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Those look like giant pop-rivets!

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Nice! So glad someone got to see this behemoth. Wanted to go to Marshall today but the weather didn’t cooperate (Decided to head to Galveston to watch other stuffs).

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Now that is steampunk…

Have you ever ridden a steam train? Instead of a steady movement, it is an interesting series of pulses.

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Robin and I got there yesterday to see it in Marshall after it came in. Our son, David, chased it and got some great video of it on the tracks. :slight_smile:

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Been on several steam trains and that is so true! Makes you sleepy.

I wonder if the higher number of drive wheels on a freight engine makes it smoother?

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Shouldn’t make a difference as they are all in sync. The driver rod from the steam pistons is constantly changing speed like piston in a car engine: comes to complete stop then reverses direction.

Never though about it, but are the LH & RH wheels in sync or out of phase by 180 deg for smoother running or together for more peak torque at start-up?

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Interesting. I never thought about the sync of the drive system. I guess when the engine is 1.2 million pounds plus untold millions of pounds being pulled, high torque would be great.

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Just my suspicion, but I think ‘not per se’. Because most of the time, all wheels are driven by the same power unit, I don’t think more wheels would make it all smoother.
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The Big Boys and Challengers, on the other hand, in addition to having more wheels than most other
steam locomotives, are in essence 2 locomotives in one chassis, meaning they have 2x the “normal” number of power units, e.g.
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and, if they’ve phased properly, should provide “smoother” pulse generation. On the other hand, I’ll bet there’s only so much “phasing” they do, since I’m not sure the two “power units” are linked other than through steam piping…
Here’s a shot of the BB pulling in, and you can see the “out of phase” on the two units on the starboard side


Question is, does this make them smoother? Dunno…
They WERE built to haul freight, which, generally, doesn’t care about smooth…

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Here’s some video of a BB doing honest-to-goodness work… Still unsure about “phasing”…

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In the last photo you can see the two sets are about 90 degrees out of phase, if the opposite side were the same, then there could be set every degrees going through maximum power or 4 pulses per revolutions which should make it feel smoother. E.g. 2 cylinder engine vs 4 (2-cycle engines most comparable).

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It is doubtful there is any physical connection between the sides or some kind of differential would be needed to take curves.

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I was imagining more fore/aft, and more of a valve timing thing, but nevertheless, I reckon they all stand alone…

The geometry of the wheel curve where it meets the rail is made so it floats up or down based on on radius curve. Trains have a minimum radius for turns.

Rail Geometry

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And in the case of the Big Boy (and other large steam engines such as the Challenger class), each of the two driver sets are articulated allowing the drivers to swivel.

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I understand that, but each wheel directly across on engines and on the car trucks are on solid axles. When going through a turn they travel different distances. The geometry of the wheel and rail allows them on float up on down and allow them to travel differences so they don’t “scuff” or gall the rails/wheels. Obviously there is a limit to how much they can take out and that is where minimum radii of curves come in.

It’s really a pretty elegant engineering design in its simplicity. But very sophisticated calculations. I love reading about how they calculate pulling capacity and accelration: friction between drivers and rail is main limiting factor.

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