Big Boy

Big Boy. (Visible are accordion styrofoam ramp sections.)(Photo by BobbaLew.)

Union Pacific (UP) railroad’s “Big Boy” 4-8-8-4, the largest railroad steam-locomotive ever built.
The other day (Saturday, February 27, 2010) I visited my old friend Art Dana (“DAY-nuh”).
Art is the retired bus-driver with fairly severe Parkinson’s Disease.
For 16&1/2 years I drove transit bus for Regional Transit Service in Rochester, NY, the supplier of transit-bus service in Rochester and the surrounding counties.
My stroke October 26, 1993 ended it.
Dana was slightly ahead of me in seniority, and was a mentor of sorts. His outlook on the job, go-with-the-flow, became mine.
Dana and I have similar enthusiasms; hot-rods, trains, model airplanes.
Dana’s wife died, and he no longer drives much.
Even though only 69, the Parkinson’s has him weak and frail.
He’s no longer the Dana I knew, but the old orneriness is still there.
Despite frailty, he’s set up an HO-scale running track in his basement. He’s a model train buff.
I’m not, but interested in what he has.
He had purchased a used model of a Union Pacific “Big Boy,” and the intent was for us to go get it, and thereafter try it out on his running-track.


The real thing. (This locomotive is on display at Steamtown in Scranton, PA.)

The Union Pacific “Big Boy” was the largest railroad steam-locomotive ever built.
Not the heaviest, but at 136-feet 10-inches including tender, the largest.
Only Chesapeake & Ohio railroad’s “Allegheny” (2-6-6-6) was heavier — as I recall. (I can’t find an Allegheny’s engine weight.)
UP went with the Big Boy to avoid helpers in the Wahsatch (“wah-SATCH”) mountains in eastern Utah and western Wyoming.
Union Pacific was the eastern half of the first transcontinental railroad finished in 1869.
As such it crossed the Great Plains, and the Continental Divide; although it did so at the easiest place, at Sherman Hill in eastern Wyoming.
There you’re not confronting the Front Range of the Rocky Mountains.
Other railroads did later, but not the first transcontinental.
There were grades, though. Primarily the Wahsatch Mountains, and the long grade up Sherman Hill to the Continental Divide.
The Wahsatch was the most difficult.
A lot of Wyoming is open and arid, almost desert.
That openness could allow easy curvature and giant locomotives.
UP now owns and operates many of the railroads in the west, including the western half of the first transcontinental, Central Pacific, which became part of Southern Pacific (SP).
Central Pacific took an especially difficult route east from San Francisco, directly into the Sierra Nevada mountains, inundated by heavy snows from the Pacific.
Central Pacific had to do a long climb up to Donner Pass to a summit at 7,042 feet above sea-level.
Union Pacific now owns and operates the line.
Keeping it operable in all that snow is a challenge.
Continual plowing and snowblowing has to be done, and a lot of the line is under snowsheds.
Southern Pacific had a covered roundhouse at the summit for servicing and turning helpers.
They couldn’t do it out in the open; there was too much snow.
Southern Pacific had steam-locomotives similar to the Big Boy, but they were oil-fired and cab-forward.
Oil-fired because SP didn’t have easy access to coal.
Firing with fuel-oil allowed the engine to be flip-flopped; cab and firebox ahead.
The largest cab-forwards were 4-8-8-2, a four-wheel pilot-truck under the cab and firebox. But they weren’t as big as the Big Boy.
Union Pacific always had large engines.
They even had a double diesel, the DDA40X. Two 3,300 hp turbocharged diesel engines in a single chassis, two four-axle trucks — in other words, eight traction motors.
UP also had the Challenger wheel-arrangement, 4-6-6-4, before the Big Boy. (One is still extant, #3985. I’ve ridden behind it.)
UP’s Challenger could boom-and-zoom, but so could the Big Boy.
The only drill was getting it to stay on the track.
But doing so wasn’t that difficult. Track could be designed for it, and curvature on UP was slight.
The biggest challenge was the grades, which was the whole point of the Big Boy.
A 150 square foot fire grate, big as a living-room.
And a 300 pounds-per-square-inch boiler-pressure, powering four drive-pistons directly.
The name “Big Boy” came from some UP shop-worker chalking “Big Boy” on the front of the smokebox.
Two four-axle driver-sets, sixteen driving wheels of 68 inches in diameter, eight to a set.
Not 80-inch, but still quite fast. (The Challenger was 69 inches.)
540,000 pounds on drivers, 350.2 tons locomotive weight; built by American Locomotive Company (Alco) in 1941 and 1944.
At the end of their service-careers, Big Boys were being used up Sherman Hill at a good clip.
A Big Boy could move a long heavy freight single-handed at about 50 mph; often faster.
Or you could double the Big Boys for longer freights.
It was a lotta power in a single unit, but multiple-unit diesels spelled their doom.
Multiple steam-locomotives are multiple crews; multiple diesels can be operated by only one crew.
Even double diesels are silly, when you can multiple single-unit diesels and get the same pulling power.
Engineering a Big Boy for HO model-railroad operation is an awesome challenge.
In the real world a Big Boy could negotiate nothing tighter than 20 degree curvature — a 40-inch radius curve in HO.
HO does good if you can do half that; 20 inch radius.
Try to fit a 20-inch radius 180 on the end of a 4x8 sheet of plywood.
Scaled up, in the real world, a 20-inch radius curve is industrial track; so tight a Big Boy would climb off it.
In the real world the rear set of drivers was attached firmly to the boiler.
Only the front driver-set was hinged.
But not in the model-railroad world.
With Art’s Big Boy both driver-sets swivel. It has to be that way for such a long locomotive to not derail.

Photo by BobbaLew.

Look at the articulation on this baby! (Around the gigantic glue-bottle — here it comes!)

In the real world, articulation of the front driver-set might be about three-or-four feet right or left. In other words, the cowcatcher and headlight, if mounted thereto, might offset three-or-four feet right or left of the boiler front, the smokebox.
The front of the boiler rested on a sliding plate atop the front driver-set, so the boiler could swing side-to-side.
But that’s nowhere near enough for the 20-inch radius curvature of HO model railroading.
In Art’s Big Boy both driver-sets have to swivel, and the pilot ends up about 10-15 scale feet beside the boiler front in a curve.
So the cab at the rear of the locomotive also swings out in a turn; something not seen in the real world.
Art’s Big Boy is at least 1&1/2 feet long from smokebox front to cab. The only way to get that thing around a 20-inch radius model railroad curve is to swivel everything well beyond reality.
Yet it’s impressive to watch, even though unrealistic in the turns.
And it runs great.
“People have gotta see this thing,” I kept telling Art.
Art also had another thing for me.
He had purchased two boxes of bendable accordion stryofoam ramps, which assembled gave two 2-percent grades. One up and then one back down.
Two percent is pretty steep in real railroading, but can be done with helpers.
Two percent in model-railroading looks like nothing. Model-railroading often sees four percent. The grade on my friend’s HO layout in 1958 was at least six percent or more. Plus it was a loop of 18-inch radius. —Couple five cars to an engine, and it stalled.
Four percent in the real world is almost impossible.
The driving-wheels would probably adhere to the railheads, but the train might hafta be broken into three-or-four parts.
A diesel-electric locomotive would adhere to the railheads, since they apply constant torque.
A side-rod steam-locomotive would probably start spinning, since torque is intermittent; a function of piston thrusts.
Art had already glued various styrofoam ramps together, yielding one ramp of four parts, and one of five.
After that he was left with seven ramp pieces, all of which had been jumbled, so no one knew which went to where.
“I was hopin’ ya could help me, Hughsey; figure this all out,” Art said.
Total mental wipeout on my part.
At first.
But after a while I started experimenting. The idea was to get the matching butt-ends glued together, to make a complete ramp.
“This ramp has five parts, Art,” I said. “Where are the others?”
“And this other ramp has four parts; I need four more.”
I started measuring ramp butt-ends, to find the two identical ramps of those seven remaining. I could thereafter separate the unused ramps into two separate groups.
That completed, I started matching butt-ends to make a complete ramp.
But a completed ramp — four-inch rise — is 16 feet long.
I began assembling ramps to only a three-inch rise, which deletes two sections each — maybe four feet per ramp.
“But Hughsey, what about these other ramps, that take me up to a four-inch rise?”
“I don’t think your table is big enough, Art,” I said.
Thinking about this later, two times 16 feet is 32 feet total. A layout table about 9 by 5, which Art’s is, is 28 feet circumference without curvature.
“We can do three-inch rise, but no higher without a bigger table or loops galore,” I said.
“What about this bridge?” Art asked, handing me a beautiful through-truss he got for $18. It already had track on it, and looked great.
“That’s the whole point of these ramps, Hughsey; to get up to this bridge.”
“How ‘bout 2&1/2-inch rise?”
I tried it; “nope; looks weird.”
“Not high enough,” Art said.
“Gotta be three,” I said. “That’s as high as the average bridge in the ‘60s, but probably not high enough to clear doublestacks. For that ya’d need four inches.
But your table ain’t big enough to accommodate two 16 foot ramps.”
The bridge was about a foot-and-a-half long.
“What about on the end?” Art asked. We’d had it on a table-side.
“I don’t think so, Art,” I said. “Do that and the curves approaching the bridge are way too tight. That bridge gobbles up a foot-and-a-half of table width.”
“Well thank you Hughsey,” Art said. “I sure am glad you could figure it out.”
I felt rather sheepish — “amazed I could,” I said.
I left without my rubbers. Had to drive all the way back to his house to get ‘em. “And yet we managed to figure that sucker out,” I said.
“If my head wasn’t firmly attached, I’d leave it behind too,” I said.
“Me too,” Art said. “I know all about it.”