The German Legend: How LZB Paved the Way for High-Speed Rail

LZB (Linienzugbeeinflussung), which translates to “Linear Train Control,” is a continuous cab signaling system that revolutionized high-speed rail in Germany (and later Spain and Austria). Before ETCS became the European standard, LZB was the only way to drive trains safely at speeds up to 300 km/h.

The 160 km/h Barrier

Why was LZB invented? In railway physics, there is a golden rule: “Above 160 km/h, human drivers cannot reliably observe lineside signals.”

At high speeds, signals flash by too quickly, and the braking distance of the train exceeds the distance between signals. LZB solves this by removing the need to look outside. It brings the signals inside the train, displaying speed limits and target distances on the dashboard.

The “Cable in the Track”

The most distinctive feature of an LZB-equipped line is the visible cable running down the center of the track.

• Continuous Data: Unlike balises which transmit data only when passed over, the LZB cable loop provides constant 2-way communication between the train and the control center.
• Electronic Vision: The system “looks ahead” up to 10 kilometers, allowing the train’s computer to calculate ultra-smooth braking curves for efficiency and passenger comfort.

LZB vs. ETCS

While LZB is a highly reliable and proven technology, it is considered a “Legacy System.”