Winter Wonderland.

[BaltACD]

jeffhergert

 

MidlandMike

There was a story in today's NewsWire about a CPKC train in icy Iowa that stalled on a hill and started sliding back downhill in emergency, headed to the BNSF mainline diamond in Ottumwa, with a BNSF train stopped across the diamond.  The CP train finally stopped 20 feet short of the crossing, and the BN train had been warned and moved.

https://www.trains.com/trn/news-reviews/news-wire/tense-moments-but-no-disaster-after-train-stalls-on-cpkcs-rutledge-hill-in-iowa/ 

From the Steel Highways railcam.

https://www.youtube.com/watch?v=1L3CxHtsO5k

Jeff

After stalling, if you don't apply the 'train brake'; GRAVITY for the WIN!

[Euclid]

I have not seen any information as to what actually caused this runaway.  Was it ice on the rails, or ice on the brake shoes?  I would guess it was ice on the brake shoes.  The train was sliding back with the brakes in an Emergency application, so this was the maximum potential braking effort. 

 

If the train started up the grade with sufficient ice/snow on the rails to cause a loss of adhesion, it would have stalled while moving forward.  Apparently that is what happened. 

 

But the ice/snow would have been cleaned off the rails quickly by the trailing cars.  So when the backward runaway began, 99% of the train would have been on clean rail. 

 

However, the water/ice thrown off the wheels may have ice-glazed the brake shoes while no brake application existed.  If that was the case, the uphill stall may have been caused by a loss of adhesion on the locomotives.  Then once it stalled, an Emergency application was made to hold the stopped train in order to prevent it from rolling backwards. 

 

But if all the brake shoes on the cars had a glaze of ice that developed while the train had been underway with no brake application for some time; the ice-glazed brake shoes may have failed to prevent the wheels from turning, after it stalled and the Emergency application was applied.

[Ulrich]

My money is on ice on the rails/lack of sufficient adhesion to hold the train. If ice on shoes were the issue we would see alot more brake related accidents in the winter time as shoes ice up and fail... we would see wide spread failures, not just the odd one on a grade like this one. 

[BaltACD]

Ulrich

My money is on ice on the rails/lack of sufficient adhesion to hold the train. If ice on shoes were the issue we would see alot more brake related accidents in the winter time as shoes ice up and fail... we would see wide spread failures, not just the odd one on a grade like this one. 

Have never seen a condition where REPEATED wheel movement on the top of the rail didn't end up with wheels getting down to steel.

[Backshop]

Ulrich

 

 

Backshop

I wonder how autonomous railcars would do in this situation, since this is the area that some proposed to use them in?

 

 

 

 

 

Same laws of physics would apply.. likely they too would slide, although the emotive radio chatter would be absent.. 

Would a third locomotive on the back have helped? Sounds to me (and I'm no expert) like a failure to plan for conditions. not the crew's fault, but someone somewhere along the line could have predicted this and added a unit.. or wait for conditions to improve.  

 

I was speaking more towards Jeff's "fun" day. Sorry that I wasn't clearer.

[adkrr64]

I would opine that it was snow/ ice on the brake shoes. Air brake and train handling rules often contain provisions that the engineer must peridocally apply the brakes in snowy conditions order to clean out any snow/ ice that may have accumulated and to ensure brake effectiveness. Normally, the engineer would do this when approaching a location where the brakes will be needed, i.e. approaching a downhill section or a siding or stopping point, but it would be counterintuitive to do so on an uphill climb.

The other reason I am thinking snow on the brake shoes is that the train did eventually stop itself. As it was rolling backwards, the brake shoes eventually cleaned out the snow as they slowly heated up, and the brakes gradually began to grab. It is the same reasoning as to why you apply the brakes before you need them - to give the brakes time to clean themselves of snow and warm the shoes to where they will be effective. Of course I have no odea of the territory, so it could also be that the rear portion of the train got to a flat enough section of track where gravity was less of a factor.

[jeffhergert]

The incident happened on Rutledge hill, named for the siding at the top of the hill. Rutledge was also the junction with the original main line from Marion/Cedar Rapids and the current main line from Davenport. The original line became a secondary branch and was abandoned in 1980.  The hill had the only regularly assigned helper district on the MILW east of the mountain districts in the steam era. 

Ottumwa is a crew change point between Nahant (Davenport) and Kansas City. The hill isn't long, but steep and on a curve. When the rear end was in the BNSF interlocking it was on the flatter portion.

Jeff 

[Euclid]

adkrr64

I would opine that it was snow/ ice on the brake shoes. Air brake and train handling rules often contain provisions that the engineer must peridocally apply the brakes in snowy conditions order to clean out any snow/ ice that may have accumulated and to ensure brake effectiveness. Normally, the engineer would do this when approaching a location where the brakes will be needed, i.e. approaching a downhill section or a siding or stopping point, but it would be counterintuitive to do so on an uphill climb.

The other reason I am thinking snow on the brake shoes is that the train did eventually stop itself. As it was rolling backwards, the brake shoes eventually cleaned out the snow as they slowly heated up, and the brakes gradually began to grab. It is the same reasoning as to why you apply the brakes before you need them - to give the brakes time to clean themselves of snow and warm the shoes to where they will be effective. Of course I have no odea of the territory, so it could also be that the rear portion of the train got to a flat enough section of track where gravity was less of a factor.

 

I agree with your conclusions.  I have never seen rail with ice on the running surface immediately after just an engine ran over it let alone a whole train.  The video of the runaway in this case is too dark to show whether the wheels are turning or not. 

 

If they are sliding on the rail, they are not turning.  If they are turning, the Emergency brake application is not holding.  If it is not holding, it is either because the brake shoes are glazed with a layer if ice; or the Emergency brake application has leaked sufficiently from the brake cylinders to release the train to movement by gravity. 

 

I would think the crew could have seen whether the wheels were turning, especially if they walked back to the trailing end of the first engine.