Hippo sighting

Two I1sa’s ready for duty. (Courtesy Joe Suo Collection©.)

—The January 2018 entry of my Audio-Visual Designs black-and-white All-Pennsy Calendar is two I1sa Decapods (2-10-0) in Northumberland, PA.
They are probably preparing to take the famous Mt. Carmel ore-train up to Lehigh Valley Railroad at Mt. Carmel. From there the ore will continue to Bethlehem for its steel mills.
The ore probably came by ship to Pennsy’s Philadelphia docks. It was transloaded for delivery up Pennsy to Northumberland. There it will become the famous Mt. Carmel ore-train.
When first put in service after 1916, the I1s was so big crews called ‘em hippos. They’re not modern, mainly a gigantic 2-8-0 Consolidation with an extra driver-set.
Other railroads had Decapods, but only Western Maryland had Deks as large as the I1s. I1sa is a modification of the original I1s. “S” stands for superheat, although by then most steam-locomotives had superheat. I think all the Pennsy Deks were superheated — the letter “s” later fell out of use.
“A” was a modification of valve-events whereby steam was admitted to 78% of piston-stroke instead of the original 50%. This was probably to better use steam that HUGE boiler could generate — although I’ve heard Deks run out of steam (I have recordings).
The I1sa wasn’t a modern steamer with a high-capacity boiler. Its firebox grate was only about 70 square feet, a standard Pennsy firebox (the K-4s Pacific (4-6-2) is also 70 square feet. The Dek also lacks a combustion-chamber. Modern high-capacity steamers had combustion-chambers and 100 square-foot fire-grates.
Pennsy’s Dek also suffered many of the problems 10-drivered steamers have.
Mainly it’s long heavy drive-rods on small drivers, drivers too small to adequately counterbalance heavy side-rod weight.
The side-rods had to be heavy enough to withstand what a Dek could put out. Making them long enough to power five driver-sets made ‘em heavier yet. A K-4 was only three driver-sets; plus its drivers were much larger, so could accommodate more counterweighting.
A K-4 has 80-inch drivers; a Dek is 62-inches.
Deks rode rough. Minimal counterweighting with heavy side-rods limited a Dek to about 50 mph. And that was if you could stand it. Heavy vibration slammed you up-and-down.
Deks were the first Pennsy engines with stokers. Coal consumption was so extreme even two firemen couldn’t keep up. Deks were also hard to fire.
The Dek’s gigantic boiler/firebox made two other locomotives, the K-5 Pacific, and also the M-1 Mountain (4-8-2).
Only two K-5s were built. That boiler was too much for three driver-sets.
But the M-1 was probably the most successful steamer Pennsy had. The M-1 also had a combustion-chamber.
Pennsy had another 10-drivered steamer, its J-1 2-10-4. The J-1 wasn’t a Pennsy design; the railroad needed new power for WWII, but the War Board wouldn’t allow them to develop their own new freighters. Pennsy had to shop existing power on other railroads.
The J-1 is Chesapeake & Ohio’s T-1 Texas, also a 2-10-4, but slightly restyled. Its boiler/firebox is radial-stay T-1, not Pennsy’s trademark slab-sided Belpaire.
Furthermore the J is modern power. C&O’s T-1 isn’t Lima Locomotive, but it follows’s Lima’s “SuperPower” principles.” Mainly a HUGE boiler/firebox with appliances that enhance steam generation, The T-1s were made by American Locomotive Company.
After the war Pennsy developed even bigger 10-driver power, but they were duplex to reduce side-rod weight — 10 drivers, but four drive-pistons. Two powered six drivers, and the second two powered the four remaining drivers.
The J-1 suffered the same problems as any 10-driver steam-locomotive, mainly a HUGE rod-set to power five wheels per side. But those wheels are larger (69 inches) so could accommodate more counterweighting.


The Mt. Carmel ore-train. (Photo by Don Wood©. —To my mind, this is his best picture.)

An I1 was difficult, yet Pennsy had many, 598 total. They were especially good at mountain railroading. Pennsy’s Mt. Carmel branch is uphill. The extremely heavy Mt. Carmel ore-drag got two Deks pulling, plus two more pushing = four Deks total.
I was told the last steamer used by Pennsy was an I1 dragging coal into Altoona (PA) on November 27, 1957. —But I was also told the last Pennsy steamer was L-1 class 2-8-2 No. 2369 from Renovo on December 2, 1957.
Whatever. Both the I1 and L1 are early 20th century — fitting for Pennsy steam-usage ending with a whimper.
The last steamer on my beloved Pennsylvania-Reading Seashore Lines (PRSL) was 5351, a K-4 Pacific, on November 2, 1957.
A ex-Pennsy 0-6-0 switcher remained in service on Union Transportation Company in New Jersey until July 17, 1959.
The Deks pictured use the gigantic “Coast-to-coast” tender, probably purloined from a retired Mountain or J. The Deks weren’t first used with a “Coast-to-coast.”