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I played a little hooky from work this morning to join other gawkers on an overpass as this machine came through our town.


Big Boy coming through Iowa - K1ii, FA43

For those who don't know about this engine,

Here is an article about the restoration

and

Union Pacific's site about the 150th anniversary of the Transcontinental Railroad and this tour.

Great capture! Looked at your links thanks for sharing. Too bad it isn't coming through St. Louis.

A beautiful piece of history! Nice shot, sir!

It must be huge. We used to have a Beyer-Garratt loco in Canberra, and according to Wikipedia, it was half the weight.

New South Wales AD60 class locomotive - Wikipedia

Yes; though not abnormally tall, since of course they can't grow things that direction, being constrained by overpasses and tunnels. Instead it's quite long, and probably the heaviest steam engine ever built. And all those drive wheels! Though you can't see them from my vantage point.

Not quite the heaviest, I think the Pennsy S2 holds that distinction, although there was only 1 of those built. I really, really wish 4014 could come my way but it'd never make the tight turns here in New England plus there isn't a turntable anywhere around here big enough for it.

In their respective wikipedia articles, the Pennsy's total weight is listed at 1,032,100 pounds and the Big Boy at 1,250,000 pounds. The Pennsy's claim is worded as "largest, heaviest and fastest direct-drive turbine locomotive design ever built" and I don't know enough about steam engine variants to make complete sense of that. Were they not taking the BB into account, or are they saying it's a different class of engine?

But in any event, each of them qualifies as heavier than a Boeing 747.

Quick flickr video of the same crossing, cropped from 3:2 to 4:3 just because the DSLR shooter who camped on the bridge to the left of my tripod and promised not to get in the shot turned out to have bigger elbows than he realized.


Big Boy 4014 - video

Sure, it's the same reasons that the Beyer-Garratt was articulated; keep the height low to fit in tunnels, but increase the power to haul more weight while keeping down the weight on each axle.

I stand corrected, I was thinking the 1 million pounds of the S2 didn't include the tender but it does. The S2 is very much a different class of engine from the Big Boy. In the Big Boys, the steam drove pistons while in the S2 the steam drove a turbine. Interestingly, Union Pacific experimented with turbine locomotives also but they were gas turbines rather than steam.

Late model Big Boys (#s 4019-4024) were actually a little heaver then the first batch (#s 4000-4019) by about 9 or 10 tons. Without the tender, the other contender for heaviest engine is probably the Allegheny 2-6-6-6s which had more horsepower than Big Boys but--if I am remembering correctly--had less tractive effort.