Who decides how many cars go onto a freight train and the priority given to the individual cars to be assigned to the train? Or maybe a better phrase is coupled to the train.
Who decides how much power the train needs to complete its run?
I don't have any thing on COVID-19 or politics, but I'll keep thinking about it.
It depends.
Priority can be given to "old dates", cars that have sat in the yard for over a day, or priority can be given to large blocks of cars that have just arrived, and can easily be added to another train.
The railroads know how much horsepower per ton is required to get a train over its route, and most freights are loaded down to this point, unless they reach the maximum length for that route first (this is also a preset value, and is determined by siding length, downstream yard capacity, or sometimes by the undulating track profile on branchlines).
Each train has a plan that includes an "ideal HPT", which is usually higher for priority intermodals than for bulk unit trains and mixed freights on the same route.
Of course, all of this can change on a daily basis depending on yard congestion, bad order (defective, broken down) cars or locomotives, track defects or other incidents that block off parts of the yard (more common than you would think). This can result in trains departing far shorter or lighter than they 'should' have been, and then extra long trains or extra sections of the same 'schedule' are run to catch things up.
It is also not uncommon for 'through trains' to be given extra switching work at enroute locations to minimize delays to other cars, or to fill out a train that departed undertonnage. Even priority intermodals are not completely immune to this.
I'm speaking from my experience on CN in western Canada. Other locations and railroads may vary.
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'Who' is a collective decision process. Yardmasters build trains in accordance with the carriers Operating Plan for the particular location. The Operating Plan specifies the block designations that each train carries. The Chief Dispatcher and/or Power Bureau are responsible for assigning power to the train the Yardmaster has built - different carriers have different positions responsible for assigning power to trains. Terminals normally forecast the number and size of the trains they will need to operate 24 to 36 hours in advance of the scheduled departure time for any specific train schedule. When the traffic forecast for a particular train exceeds the normal limits for that train, decisions are made by operating officials as to if the traffic will be held or if a Extra train will be operated for the traffic.
The Operating Plan is what sets the priority and length and/or tonnage parameters as well as the blocks and their order that are applicable to the train.
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Thanks for the thoughful responses.
To what extent do the Yardmasters or others rely on computer programs to help them optimize the make-up of the trains?
JPS1Thanks for the thoughful responses. To what extent do the Yardmasters or others rely on computer programs to help them optimize the make-up of the trains?
Almost exclusively - computers are how the basic information reaches the individuals that have to make decisions based upon the information they receive.
Does it require cajones the size of boulders to override the recommendation of the computer, or is there more latitude to make expediant decisions? Say, for example, a yardmaster tacks on an 500 tons to clear another yard track and the train stalls on the hill.
rrnut282Does it require cajones the size of boulders to override the recommendation of the computer, or is there more latitude to make expediant decisions? Say, for example, a yardmaster tacks on an 500 tons to clear another yard track and the train stalls on the hill.
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I have noticed a drastice drop in the number of "extra sections" here in my little corner of NS since PSR took over the thinking.
rrnut282I have noticed a drastice drop in the number of "extra sections" here in my little corner of NS since PSR took over the thinking.
Most likely not a direct function of PSR but more likely the softness of the manufacturing economy (as opposed to the computer driven Stock Market economy).
rrnut282 I have noticed a drastice drop in the number of "extra sections" here in my little corner of NS since PSR took over the thinking.
There are several individuals on the Deshler chat who collectively keep a train count daily.
At the beginning of the year the junction saw around 60 trains per day. Once the panicdemic struck, that dropped into the low 40's. Most days now there are around fifty, and the number continues to climb.
There have been several instances where it's known (and obvious) that two symbols have been combined into one.
Traffic was down, and is rebounding.
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