Schedule and physical plant: tradeoffs

Projects to improve the physical plant are planned hand-in-hand with the future schedule, which in turn reflects market needs. Optimizing the physical plant can involve difficult choices.

For example, between Zurich-Altstetten and Schlieren, crossovers permit westbound trains to change tracks at 65 km/h, which means a loss of about a minute, and eastbound trains at 95 km/h, which means they only lose 30 seconds. But the 95-km/h crossovers are more than twice as long and therefore cost much more to fabricate and install.