Molecular trains on different tracks

The cilium, an antenna-like structure in the cell, undergoes rapid assembly and disassembly. This is enabled by a bidirectional train-like transport system called intraflagellar transport (IFT). In healthy cells, IFT happens collision free and without traffic jams, but if IFT fails, various human pathologies arise. Recent findings show how the cell prevents collisions by placing trains going in opposite directions on different rails.