A rolling stock question.

I was railfaning yesterday, here in Syracuse, NY. I noticed a marking on the cars. It said, "Place jack here." I realize that this is to place a jack, however; why does the placement matter? I s this area for rerail also in case of an derailment?

Mattliverpool wrote:I noticed a marking on the cars. It said, "Place jack here." I realize that this is to place a jack, however; why does the placement matter?

“JACK HERE” points are points are where a car’s structural underframe is capable of supporting the entire weight of corner or end of the car.

Car structure between these jacking point mights be only light corrugated sheet metal, wooden flooring, stamped steel floor support cross members, etc. These areas are designed only stiff enough to support an evenly distributed floor load applied from above etc. – not to pick up the entire weight of the car.

For an analogy look at a modern automobile. Chances are if were you to stick a hydraulic bottle jack under a rocker panel then try to lift the car, the jack ram would punch thru the rocker panel rather than lifting the car. To avoid this most automobiles have designated jack points, usually beneath the front and rear bumpers, or at special "lifting points" integrated into the lower body pan. ...FB

In a nut-shell to answer your question as to why a car would be lifted or jacked-up, it would be done if heavy repairs needed to be done to the rail-car, such as changing wheels.

As for derailments, minor derailments such as one or two axles off the rail, are fixed by pulling the car back on with a locomotive using blocks of wood to guide the wheels back onto the rail. Bigger derailments would require a crane or hulcher. (a.k.a. side-winder).