Freight sliding back down a grade because of snow?

Caught an article on Trains. Com about a Canadian Pacific freight stalling on a grade in Iowa , then sliding back down the grade toward a diamond holding a BNSF freight .
Number of dramatic quotes via radio by the crew but my question is ::
Crew said they were ‘sliding back to the yard whether they like it or not ,in ‘emergency but gaining speed’ .

In the end stopped just 20 feet from the diamond .

What would they be trying to do by ‘putting into emergency ‘?

Mark

Apply the brakes as quickly as possible in hopes of getting the train to stop rolling backwards.

In deep snow the train can be almost like a sled. The brakes may be on but either there is enough ice between the brake shoes and wheels that they are ineffective, or the wheels may be sliding on icy rails even though they are not turning.

The same can happen with wet leaves on the rails...

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Says grade was 1.6%
Is that figured ‘per mile’.?

I take it that’s a lot?

It can be any distance. It's the ratio of rise (or drop) in a given distance. If you measure out 100 feet, and one end is 2 feet higher, that has a 2% grade. If it rises 52.8 feet in a mile, that's a 1% grade.

I don't know what your definition of " a lot" is, but I can tell you I have ridden a large steel toboggan down a 1.92% grade with another train standing at the bottom, and it was a ride I'll NEVER forget!

As an armchair driver I’d say anything not on the level would be alot to me.

Would you have a chart showing the grades on your route??

“In anticipation of”?

It sounds like you are describing the second train to stall on the same grade within days of the first train. The first train was #251 bound for Superior, WI powered by an AC4400CWM and a ES44AC. This train did slide all the way through the diamond crossing with the BNSF, just missing a BNSF empty coal train by less than a minute. The second train was a loaded coal train for Muscatine Power and Light with an SD70MAC leading and a SD70ACe trailing, with a SD70MACe and SD70ACe DPU on the end. The second train stopped before fouling the crossing.

Practices vary from one line to another, there IS a document called a "profile" which shows grades, curves, bridges, and various other things. However those are more often used by Maintenance of Way forces. Some lines do make these available to transportation crews.

Engineers must be qualified on the physical characteristics of the lines they operate over. If unfamiliar with a route, a "pilot" is called, someone who IS familiar and can give the new guy pointers as they go along. I'll note the "new guy" might have 40 years experience, but either has never been over the line in question, or has not been over it in a long time. "a long time" is sometimes considered to be 1 year but again that may vary.

You may also be interested that not all grades are the same even with the same slope. Another factor which is often just as important is curvature. There is resistance in a train and a snake-like line might have enough drag to offset the downhill grade, or even require some throttle. On a tangent (straight track) a lesser grade might actually require more braking than a steeper one with curves.

There are a lot more factors involved than just get on, release the brakes and open them up.