Powering Trains (by tonnage)

On the NS, when Loco’s come in from the road, they are inspected, refueled, readying them for return to service; a call from the “power desk” informs the terminal employees what loco’ number’s to “come together” (by rated-horsepower)…for train #XXX (by tonnage) …(prospected) engines can be load-tested (if computer aboard) and if rated horepower is off no more than 10%, it ’ will run.’ GE’s (4 cycle) are slower to throttle-up …EMD’s (2 cycle) are quicker to respond … had a Engineer to tell me that for him, he’d rather have the EMD in the lead; otherwise you would ‘feel’ the EMD nudging you in the rear - BUT …on mountainous grades, the EMD’s would begin to drop-off sooner, than the GE’s, as they would drop down slower; DIGGIN-in and really STARTING TO PULL - …have seen several EMD F-7’s throttled-up (8th notch), slowly come ‘trembling’ to a stop …(too much tionnage) …engineer (knocking- back to idle) - radioing the “tower” to send help, i.e. a switcher('s) to get them on-in to the terminal. Every RR probably operates somewhat different. Hope this info helpful -

So this was an FYI-type of statement…interesting. Thanks!

Yes, rr’s do check tonnage to give a train enough power. I am a former AT&SF clerk. When we would line up a train to check the waybills for the conductor, we would also run a TONTOT program that would give us the weight of the train. Then we would consult a chart that listed all types/tonnage ratings for the particular district/subdivision that that train would be running. Sooooo, if you had 2 SD40-2’s, a GP-38, and an SD–9, you could follow the chart to the rating for those engines, total them up, and compare the rating to the total train weight. If the tonnage was more than the total of the ratings for that district/subdivision, the crew would have to cut the appropriate number of cars/tonnage, to be compliant with the ratings of the consist. Yes, my choice of engines types is a little outdated. I was a clerk for the Santa Fe from 1980-1985.