As I sit home, I enjoy listening to the CN on the scanner. Most of the times I can hear the crew calling the RTC after they made their set-outs and/or pick-ups. They would give the RTC their “new” totals. Some of the time, the trains are just huge if not heavy (longest feet-wise was just over 12,000 ft southbound; car-wise was 216 northbound; heaviest was 22,000ish, southbound all from Neenah). I was wondering this:
When the crew gets the new train list with the new cars added and the conductor is re-doing the new totals, how is the length figured out. I know there are 60 foot boxes, 50 foot boxes without cushions…how is everything figured with the slack. Is there a specfic length that is entered with a car and stays with that one particular car throughout that cars life? Most sidings (CN’s Neenah and Superior Sub) are around 10,000 feet but one time I heard a train giving its new totals and then the RTC told them theyll meet one at Anton and they should fit with about 75 feet to spare. If the adding is off, there can be a little headache in the making. Just wondering.
Yes, the car’s length is given in UMLER, and stays with the car for its life (or it should!). The length is the distance between the pulling faces of the couplers (the inside of the closed knuckles), since that’s the length for which coupled cars can be computed accurately. I suspect that the length is computed with slack stretched, though I’m not sure that that’s specified anywhere. I would think that the stretched-slack version of the length would be preferred, just for reasons such as this. If the length were specified with the slack bunched, and the slack couldn’t be bunched, the difference could be well in excess of 75 feet over 10,000.
C Shave is correct that “length” is over the pulling faces. I beleive that it is measured in slack neutral condtion as I seem to recall either BNSF or UP train lists showing a “stretched length” 3% greater than “length”. This implies that carriers may adjust length to suit their purposes. I believe the UMLER instructions specify slack condition to be reported. They are very detailed.