The Amtrak derailment near Tacoma, Wash., that killed three people last week may well have been partly the individual failure of an engineer who was going much too fast. It was also, however, yet another demonstration of this country’s collective, continuing failure to invest in infrastructure.

Though their inquiries are not complete, investigators have determined that the train, which was going from Seattle to Portland, Ore., was traveling at 78 miles per hour as it approached a turn that has a 30-m.p.h. speed limit. The circumstances are eerily similar to a 2015 Amtrak crash near Philadelphia in which eight people were killed when a train derailed as it sped through a sharp curve.

In both cases, the trains were operating without the benefit of a system known as positive train control, which can automatically slow down or stop a train when human operators fail to do so. This technology is not some hot new thing. The National Transportation Safety Board has been recommending it for nearly half a century. For various reasons — including bureaucratic inertia and penny-pinching — many railroads still don’t have functioning systems in place.