Tetracycline has been studied extensively in clinical trials, with thousands of people worldwide having been evaluated. In these studies, side effects occurring in a group of people taking the drug were documented and compared to the side effects that occurred in a similar group of people not taking the medicine.
Steel ties are utilised in nearly all sectors of the worldwide railroad systems including heavy-haul, class 1s, regional, shortlines, mining, electrified passenger lines (OHLE) and all manner of industries.
Notwithstanding modern technical developments, the overwhelmingly dominant track form worldwide consists of flat-bottom steel rails supported on timber or pre-stressed concrete sleepers (railroad ties in the US), which are themselves laid on crushed stone ballast.