I am not a railroad employee, however am fortunate enough to be able to drive as many as 4 GE 4400CW locomotives in a consist, along with between 105-110 4000 bushel grain cars which are loaded on a 7500 ft. closed circular loop. The loop is on private property just off the railroad main. The first half of the train is pulled through our loading area, then, the engines are uncoupled from the 1st. car, driven forward and coupled to the rear of the last car. The purpose of this maneuver is to minimize the amount of slack take-up, as we need to start and stop at each of the 3 hopper compartments of each car and fill with grain. My question is, “What is the stress on the rail, tie, and ballast infrastructure when compairing the two different, pull/push maneuvers”?
As stated, too vague for me to answer. Your answers are going to vary with radius, track size-weight-condition, locomotive adhesion and so on.
When thinking about the simple physics of a train…the simplest analogy would be in how a single strand of cooked spaghetti behaves, When pulled it will attempt to follow what is pulling it in the straighest possible line, unless that line is changed by other forces (track structure). When pushed, it will want to accordian upon itself, unless the line is changed by other forces (track structure).
The track forces generated in your operation are not significant considering the low speed nature of the operation. However, should quick heavy, throttle operation be introduced into the equation…from either end ot the train…a derailment will result…when pulled the cars could be ‘stringlined’ off the track.; when pushed the cars could be buffed over the rails with a ‘quick’ run in of the slack.
Slack action in a train is a frequent cause of train handling derailments as the engineer did not prevent excessive forces in either buff (pushing) or draft (pulling), or the rapid change from excessive draft forces to excessive buff forces, or vice versa.
Asking about rail stress dynamics really does not apply. Stopping at every loading hatch means the train can never exceed the speed of a crawl. Consequently, virtually all of your stress is static rather than dynamic. There will be friction forces between the flanges and the inside rail (inboard when the train is pulled, outboard when the train is pushed). The resultant wear, if any, can be elimnated by flangeway lubrication.
i’m going to assume it’s one of those shuttle load grain facilities you work at…i didn’t think the employees ran the trains when they’re loading. thought it was all railroad employees.
Contracts/Rules for operating these facilities are as varied as the number of facilities that exist.
Where the loading operation would require more than one crew to deliver the train from the nearest crew change point, load the train and return to the crew change point, the carriers will endeavor to have the shipper/consignee perform the loading function thus not commiting railroad manpower resources to this operation. Your facility may differ.