The reason is that flaws in the railroad tracks are the normal state of affairs, the lead researcher Rebecca Forsberg told Swedish Radio in an interview.
"They feel they can just shut their eyes for smaller problems," she said. "Because they notice that when problems on the tracks are reported, repairs are slow in coming. It becomes normal that the tracks are bad."
The operators of locomotives are the eyes and ears with regards to the operating condition of tracks and should report normal wear, defects, or other flaws. Train operators often call in problems if they pose an immediate danger. But when problems are less urgent - for example when track sections have brushwood on them or when they make the train shake or jump - train operators may choose not to report.
"There's the sense that the customer comes first, that the train arrives on time, rather than that safety is first," said Forsberg.
In the study some train operators said there were track stretches which were "horrible to drive through." But one locomotive operator told Swedish Radio News that if reports of track problems weren't addressed, operators weren't likely to keep reporting. Train operators instead might choose to reduce their speed through problem stretches. In certain spots, the operator told the news program, one couldn't even drive the recommended speed.