2-10-4

Chesapeake & Ohio T-1 #3006 at 60 mph in Ohio around 1940. (Photo by Glenn Graybill Jr.)

The Fall 2010 issue of my Classic Trains magazine has a large feature on 2-10-4 steam-locomotives.
It claims the 2-10-4s were the “mountain-climbing, tonnage hauling giants of the Steam Age.”
Well, they were impressive, but I don’t know about “mountain-climbing.”
I always got the impression they were misapplied — that they were better at hauling tonnage at speed, than dragging up mountains.
The article also says any 10-drivered steam-locomotive was a challenge; that it was abusive of track.
10 drivers require heavy side-rods, and the driver-wheels were too small to allow enough compensatory counterweighting.
Mentioned is the fact a track-crew had to be stationed at the foot of a grade, to repair the damage a 10-drivered steam-locomotive would inflict hammering up the hill.
10 drivers also required a long, rigid wheelbase that couldn’t handle curvature.
Often drivers had to be blind (flangeless) to avoid pulling rails out of curves.
That is until lateral motion driver-boxes came into use, that allowed a driver to offset perhaps an inch relative to the wheelbase.
10-driver experiments go back a long way, clear to 1867; adding another driver-set to the 2-8-0 Consolidation. —There were 10-driver locomotives even before that.
Lehigh Valley had 2-10-0s first, two. But they were too rough for track at the time.
25 years passed before the next 2-10-0s, six Camelbacks for Erie to work Gulf Summit.

Pennsy Dek #4300, probably a builder-photo.

It was Pennsy that got serious about the 2-10-0 at first. 598 I-1 Decapods, built by Altoona and Baldwin — 123 by Altoona, 475 by Baldwin.
And they were all the same; no differentiation of classes, or major appearance-changing upgrades.
The Pennsy Deks had only one minor appearance difference.
All the Baldwin Deks had Worthington feedwater heaters; the Altoona Deks didn’t.
It was the first time Pennsy allowed any kind of appliance.
A feedwater heater is just that; it preheats the water fed into the boiler.
Pumping cold water into a boiler degrades its efficiency.
Often the feedwater heater got installed in the top-front of the smokebox, to take advantage of smokebox heat.
But the Worthington was hung on the boiler side.
I don’t know how the Worthington works.
Pennsy later widened the cutoff on its Decapods, the I-1sa.
“S” stood for superheat, by 1916 pretty much the norm.
Superheat pipes the steam back in the firebox exhaust flues through the boiler, heating the steam to much higher temperature, making it “drier.”
Prior to superheat, steam-locomotives were “wet.” The steam was only 212 degrees or so, and not as efficient as superheated steam.
Arcade & Attica tourist railroad in western New York still had two wet steam-locomotives.
“Wet” was the norm at first. Superheat came later.
Superheat came into use about the turn into the 20th century.
At first Pennsy was adding “S” to all its superheated locomotives.
By 1930 superheat was so common they dropped the “S.”
“Cutoff” is percentage of piston-stroke during which steam is admitted.
Limited cutoff was all the rage when the Deks were built, so it was limited to 50 percent.
It was found later cutoff could be increased, increasing the power of the locomotive.
The Deks were increased to 78 percent, the “A” modification.
By 1916 track had evolved enough to deal with a 10-drivered locomotive’s heavy pounding, and Pennsy was open enough so that curvature wasn’t a problem.
The Pennsy Dek had limitations. You couldn’t go too fast or it ran out of steam.
Its firebox grate was only 70 square feet, not much to keep up with a 10-drivered locomotive’s steam requirement.
But a Pennsy Dek was very powerful at slow speed — dragging freight.
Pennsy Deks saw use clear until the end of steam.
A Pennsy Dek might run 50 mph, but it was hang-on-for-dear-life.
Too much vibration. Everything hammering up-and-down.
And I doubt it could hold that speed very long.
A Dek had a large boiler, but not much steam capacity.
At that speed it would run out of steam.
That smallish fire-grate couldn’t keep up with the steam requirement of its two HUGE cylinders.
The Dek was a monster, but only if run slowly.
#4300 (pictured above) wasn’t the first Pennsy Dek. That was #790, erected in Altoona in 1916.
4300 was a Baldwin Dek. The Baldwin Deks were numbered starting with 4225 in 1922.
I had to drag out my ancient “Pennsy Power” book by Alvin Staufer, copywrite 1962 — the year I graduated high-school.
I’ve had it over 42 years; I got it in 1968.
I’ll never throw it out. I still consider it the bedrock of all Pennsy fandom; and most of all I’m a Pennsy fan.
It comes from my childhood encounter with Pennsylvania-Reading Seashore Lines (PRSL) through the little town of Haddonfield near where I grew up in south Jersey.
PRSL also ran Reading (“REDD-ing;” not “READ-ing”) steam, but it was Pennsy that looked best.
PRSL was not up to needing Decapods, so I never saw one in the flesh.
The largest freight locomotives it ran were the 2-8-0 Consolidations, or perhaps L-class 2-8-2 Mikados. (I’m not sure I ever saw a Mikado.)
The Deks were supposed to be hand-fired, but no way could even two firemen keep up with the coal demand.
The Dek was the first engine Pennsy deigned to put a coal-stoker on. Only that could keep up with the coal demand.
What the 10-drivered steam-locomotive needed was more steam capacity, which could be done with a larger fire-grate and firebox.
That required trailer-wheels, 2-10-2.
Also, hanging the firebox grate behind the driver-wheels gave it more volume. You didn’t have to shorten it to fit it atop the drive-wheels.
This also allowed taller drivers.
But not much with a 2-10-2; the firebox was still often atop the drivers.
So the 2-10-2s were still pretty much slow drag-engines, much like the Decapod.
Santa Fe was the first to get a 2-10-2, 85 from Baldwin in 1903; little more than a Decapod boiler on a 2-10-2 frame.
Railroads were quick to see the improvement in steam-capacity a 2-10-2 could have over a Decapod.
Soon over 2,200 were built, but they still had limitations. Their firebox could be larger, but their firebox grate was still small, limiting horsepower output.
Plus the 2-10-2s didn’t address the counterbalancing problems of the Decapod.
In 1929 the principal railroads controlled by the Van Sweringen brothers of Cleveland — Chesapeake & Ohio, Erie, Nickel Plate, and Pere Marquette — created a design and engineering bureau, the Advisory Mechanical Committee (AMC), to develop common locomotive and rolling stock designs.
By then Lima (“LYE-muh;” not “LEE-muh”) Locomotive Company had developed its SuperPower locomotive designs, first for Boston & Albany Railroad.
B&A had a difficult profile across Massachusetts, its greatest challenge being crossing the Berkshire mountains in the western part of the state.
Lima Locomotive Company added a fourth trailer-wheel to the 2-8-2 Mikado, making a larger firebox possible.
Lima did other things to improve the boiler’s steam generating capacity.
Primary was a combustion-chamber ahead of the firebox, which allowed more complete burning of the coal.
Other appliances were added that enhanced steam generation.
Lima’s first SuperPower engines were 2-8-2 Mikados, but the 2-8-4 (“Berkshire;” after the mountains where they were applied) allowed an even bigger fire-grate.
Even Pennsy tried the combustion-chamber; its 4-8-2 Mountain engine had one. They could be run hard at speed.
SuperPower made continuous high-speed steam-locomotive operation possible.
At last the steam-locomotive could cruise a long time at 50+ mph without running out of steam.
Lima built SuperPower 2-10-4s, but the Advisory Mechanical Committee’s first assignment was to design a locomotive that could run through on coal-trains from Russell, KY to Toledo, OH, replacing 2-10-2s and 2-8-8-2s.
At first they designed a sort of super Berkshire, 2-8-4, patterned after Erie’s S-3 Berk.
But it didn’t have enough tractive force, so they added a fifth driver-set, making it 2-10-4.
That was a success, so much so Pennsy copied it when fishing around for WWII steam-locomotives.
When WWII broke out, the Pennsylvania Railroad found itself short of power to move the humongous increase in traffic.
It also found itself saddled with old and tired steam-locomotives. They had invested inordinate sums in electrification during the ‘30s, but didn’t develop modern steam power.
Pennsy always developed its own steam-locomotives. They might buy from Baldwin, but it was a Pennsy design (e.g. the Decapods).
The War Production Board wouldn’t allow Pennsy to develop replacements, so Pennsy had to shop around.
Pennsy tried Norfolk & Western’s fabulous “A” articulated; 2-6-6-4. They also tried Chesapeake & Ohio’s T-1, 2-10-4.

A Pennsy J1.

Pennsy decided to get its own version of the C&O T-1. They called it the J1.
It was the only Pennsy steam-locomotive without the trademark Belpaire firebox.
The boiler and the firebox was the C&O T-1. They finessed the front-end somewhat, and also somewhat streamlined the cab. it looked like Loewy had blessed it.
The firebox top was round, same as the boiler courses. The standard firebox on 89 bazilyun steam-locomotives since time immemorial.
It wasn’t the square-shouldered Belpaire firebox. They couldn’t graft a Belpaire on the C&O design. The War Production Board wouldn’t let them.
By some accounts, Pennsy’s J was the best steam-locomotive Pennsy ever had.
It had all the modern accoutrements Pennsy usually eschewed. —For all its testing and research, Pennsy never developed a landmark steam-locomotive.
I always got the feeling it was somewhat misapplied in mountain railroading, e.g. The Hill over the Allegheny Mountains.
Where it excelled was where it could get rolling; 50-60 mph over level terrain.
To do that you needed boundless steam capacity, which the mighty J had.
Perhaps the Norfolk & Western “A” woulda made more sense, but Pennsy had had difficult experiences with articulateds.
They also could afford multiple crewing.