coal train question

[countryboy9770]

I watched a coal train come through St James, Mn this past week and I noticed on the front of all the coal cars it was red and the other 7/8 of the car were gray. I seen on some of the cars in the red part it said "rotary end" I believe it said. I was wondering what does that exactly mean. Ive never seen a coal train like that before so I was dumbfounded tia

 

[fran1]

Only guessing, but when they get to the power station they are unloaded by a rotary movement (turning them upside down). They go red end first so the attachment points for the tippler to grip the wagon are all in the same place when its to be tippled.

 

[bigricho]

Also, you don't get two non-rotating couplers together if they're all aligned.

 

[big_b]

The coal wagons I've seen have one rotary & one fixed coupling.The rotary is round & can move side to side as well as turn through 360deg the fixed was square moved side to side & was spring loaded for coupling cushion.These were pulled & pushed through by creeper chains between the tracks or a position er (not the loco Its only there for the ride while dumping) to the rotary unloader, the wagon in the unloader pivoted around the coupling of the wagons outside the unloader as it was turned 180deg while still coupled.The markings are so you never get two fixed couplings coupled together as it would flip the wagons outside the tumbler.
The model shows it quite well
http://www.youtube.com/watch?v=vb8_sJLmrgY
http://www.youtube.com/watch?v=CnvBtnmVt9M&feature=related
http://www.youtube.com/watch?v=iNBcnY-dhlo&feature=related

Dave

 

[jadebullet]

Yup, only one coupler has a rotator. Of course, just because it has a colored end doesn't necessarily mean rotary coupler depending on the road. It can also designate dedicated service in certain commodities. I know that the Reading had a fleet of hoppers with blue ends that were used only in sugar service in Philly.