My calendar for June 2018

Before the SD40Es were the SD40-2s. (Photo by BobbaLew.)

—The June 2018 entry in my calendar, taken a few years ago, is two Norfolk Southern SD40-2s, probably in helper service, rounding Horseshoe Curve.
Allegheny Mountain has always required helper locomotives. From Altoona railroad-west to the summit in Gallitzin is a 12-mile climb of 1,016 feet.
Getting efficiently over Allegheny Mountain was the major challenge when the Pennsylvania Railroad was laid out in the late 1840s. The goal was to build railroad that could crest that mountain without breaking up a train.
The grade had to be slight — it averages 1.75-1.8 %. That’s 1.75-1.8 feet up for every 100 feet forward. To maintain that John Edgar Thomson, original chief-engineer of Pennsy, used trickery. Horseshoe Curve was his master-stroke. The railroad looped a valley to keep the grade manageable.
Recently a tourist at the Mighty Curve asked why the railroad didn’t just trestle the valley.
“Because it woulda been too steep,” I exclaimed. Still, 1.75-1.8% required helper locomotives. But they didn’t hafta break the train. Exceed 2% and yer shortening train-length. Exceed 4% and the train had to be doubled (two sections), or even tripled.
You might get 10-15 cars up 4%. Exceed 5% and locomotives no longer hold the rail — you have to rack.
Now 15,000-ton 120-car unit coal-trains are using that same route Thomson laid out. Helpers are needed. 15,000 tons might require two 2-unit helper-sets at each end. That’s eight additional locomotives, four pulling and four pushing. That’s in addition to the two or three 4,000 horsepower road locomotives that were pulling on the flat.
But that 120-car train is not being sectioned. Thank you Thomson. It’s still the same railroad he laid out.
And part of his challenge was grading technology available then.
“How come the railroad doesn’t just tunnel this mountain?” 50 years later they might have. But in the 1840s a 10-mile tunnel was impossible. The summit tunnel is 3,605 feet. It cost less to continue using the original railroad than dig a long tunnel.
Even with helper-service — a time-consumer = stop the train, add helpers, then later stop and cut ‘em away — that railroad over Allegheny Mountain was incredibly successful.
The locomotives are EMD’s SD40-2s, six axles under a shorter hood. SD40-2s are on the longer frame of EMD’s SD45-2 (20 cylinders), which is why the locomotives have ”porches” in front of the cab, and behind the hood.
The SD40-2s did Allegheny helper-service a long time. Go back far enough and helpers were steam. When I first visited the Curve in 1968, six-axle Alco and GE diesels were being used, often with an SD-45.


A six-axle Alco pushes up The Hill back in Penn-Central days. (Long-ago photo by BobbaLew.)

Eventually the SD40-2s wore out. Norfolk Southern decided to downrate some of its SD-50s. At 3,500 horsepower an SD-50 was overstressed and unreliable. Taking them down to 3,000 horsepower, what the original SD-40s were, made an SD-50 reliable.
(SD40-2s are SD-40s with modular electronics., Anything “Dash-2” is modular electronics.)
So SD-50s were rebuilt into the 3600s, the SD40Es. Each helper-set has two 3,000 horsepower SD40Es, 6,000 horsepower per set.
That 15,000-ton coal train gets as much as 24,000 additional horsepower to conquer that mountain. But it’s not being sectioned.
When I took this calendar picture I wasn’t as savvy as I am now. But I did know Norfolk Southern was using SD40-2s as helpers.

• “Cut-away” of helpers has become quite a bit less time-consuming. Many of the 3600s have “Helper-Link,” an application that uncouples helpers on-the-fly.