Scratchbuilding a live-steam 4-6-2 Pacific. In 1:1 scale.

[California Tanker]

Well, people scratchbuild live steam locomotives all the time. Rode behind one today, actually. But not usually to this level. I guess the principles are all the same, just a little bit bigger, but damn.

BBC Video Linky (http://news.bbc.co.uk/2/hi/science/nature/7537462.stm)

http://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/60163_Tornado_2.jpg/800px-60163_Tornado_2.jpg

http://www.a1steam.com/images/stories/Keith_Drury_pics/Trust_BldgT_OpgT/2008/IARwy_DSC_7056.jpg

Three guys down the pub in 1990 had an idea. The last one was built in 1949, none survived the scrapheap. This makes it the first mainline steam locomotive built in the UK in fifty years. Rated for mainline running at 90mph.

There aren't enough GS-4s in the world, I wonder if someone in the US could be tempted...

NTM

[Dingfod]

Is that an oil burner or coal?

[ceptimus]

Coal. We never had any main line steam locos that were oil fired in the UK (other than a few experimental prototypes).

[Dingfod]

We did here, the Union Pacific "Big Boys", most if not all were oil burners, producing some crazy amounts of horsepower, rivaled only by the turbine engined locomotives of a few decades ago. One Big Boy could pull an entire train. UP ran them on mainline routes until 1958.

[California Tanker]

http://www.steamlocomotive.com/colorado/up4004a.jpg

There's a surprising amount of Big Boys still extant, though none are running.

They weren't the largest locos ever built, in terms of weight, length, or tractive effort, but are the 'generally known' one because it placed well in most every category. For example, the heaviest and most powerful in hp was the C&O's Allegheny, designed for slow coal drags in the mountains.

http://www.steamlocomotive.com/bomuseum/co1604-duley.jpg

The longest production loco belonged to the Penn, the Q2.
http://upload.wikimedia.org/wikipedia/en/2/21/Q2_front-side_view.jpg
(PRR also had the longest period, but only one S1 was built)

In terms of sheer tractive effort, the Triplexes with their 24 low-geared driving wheels, couldn't be beat.
http://www.skyrocket.de/locomotive/img/vgn__x-a__1.jpg

These days, this is the most powerful steam train you'll ever see running. A UP double-header with a Northern and a Challenger.
http://www.youtube.com/watch?v=wiio1h_4ll0

3985 just finished a three-year rebuild two months ago, and is back on the rails. Usually found hauling special excursion trains, on very rare occasions it has been used to haul actual revenue freight trains. Note the extra tenders, not many watering stops these days.

http://www.uprr.com/aboutup/graphics/excurs/my3985.jpg

NTM