How to operate and read the signaling systems in the German LZB and French TVM430 cabins.

 

Operating high-speed trains in Europe requires driving by in-cab signaling, as trackside signals become impossible to read reliably above 160 km/h (100 mph).

1. German LZB (Linienzugbeeinflussung)

LZB uses an inductive cable loop laid between the rails to provide continuous supervision up to 10 km (6.2 miles) ahead on Deutsche Bahn ICE routes.

Reading the LZB Display (MFA / Modular Cab Display)

When LZB is active, you monitor three key indicators on the central panel:

• V-Soll (Permitted Speed): Displayed as a red bug/line on the analog speedometer rim (or a digital number). This is the maximum speed you are allowed to travel right now.

• V-Ziel (Target Speed): Shown on a digital LED readout at the bottom of the speedometer. This is the speed limit you must reach at the end of the current monitoring distance.

• G-Abstand (Target Distance Bar): A vertical bar chart in the middle of the panel measuring 0 to 9,900 meters. It shows how far away the next speed reduction or stop signal is located.

• Status Lights:

  • Ü (Übertragung): Lit blue when continuous LZB data transmission is active.

  • Ende: Flashes when approaching the end of LZB-equipped track.

  • G (Brake Warning): Illuminates or flashes if you exceed permitted speed or fail to brake fast enough.

Step-by-Step LZB Operation

1.Entering LZB Territory:Transition from PZB to LZB.

1. Cross over the trackside LZB entry cable loop at speeds above 140 km/h.

2. Watch for the Ü indicator light to illuminate blue on your dashboard.

3. The conventional PZB system moves to background monitoring automatically. The V-Soll bug on your speedometer will jump to the line's maximum speed (e.g., 250–300 km/h).

2.Normal High-Speed Running:Maintaining cruising speed.

1. Accelerate up to V-Soll. If using AFB (Cruise Control), set the AFB lever to match or exceed V-Soll; AFB will automatically adjust train speed according to LZB commands.

2. As long as V-Ziel matches your current speed and the distance bar remains at maximum, no braking is required.

3.Deceleration Curve Execution:Responding to speed drops or red signals ahead.

1. When a lower speed limit or stop signal approaches, the G-Abstand distance bar begins counting down from 9,900 meters.

2. V-Ziel drops to the target speed (e.g., 160 or 000), and a chime sounds.

3. As you close the distance, the V-Soll indicator needle/bug slowly drops toward V-Ziel.

4. Action: Apply service brakes immediately (or let AFB brake) to keep your actual speed needle below the dropping V-Soll indicator. Exceeding V-Soll triggers an audible alarm and automatic emergency braking.

4.Exiting LZB Territory:Returning to conventional PZB signaling.

1. Approximately 1,700 meters before the end of the high-speed line, the Ende light flashes and a warning chime sounds.

2. Press the PZB Befehl / Acknowledge button within 10 seconds to confirm the exit warning.

3. Once the Ü light goes out, trackside signals resume authority under standard PZB monitoring.

2. French TVM430 (Transmission Voie-Machine)

TVM430 is used on French LGV (Ligne à Grande Vitesse) high-speed lines for TGV and Eurostar runs up to 320 km/h. High-speed tracks have no trackside signals; authority is governed entirely by colored 3-digit speed blocks on the dashboard.

Reading the TVM430 Display

The TVM screen shows three digits representing the current block aspect and target speed:

+------------------------------------------------------------------------+
|                          TVM430 DISPLAY CODES                          |
+----------------------+-----------------------+-------------------------+
| Display Code         | Visual Format         | Meaning / Action        |
+----------------------+-----------------------+-------------------------+
| 300 / 320            | Green numbers         | Clear block: Max speed  |
| 270 / 220 / 160      | Black text on white   | Warning: Speed drop     |
| 270E / 160E / 080E   | Yellow text on black  | Exécution: Active brake |
| 000                  | Red text on black     | Stop before next marker |
| 000 (Flashing)       | Flashing red          | Emergency stop required |
+----------------------+-----------------------+-------------------------+

• Plain Numbers (Green or White): Target speed allowed in the current block.

• "E" Codes (Yellow digits on black): Exécution block—you must be actively braking to reach the specified speed before crossing the next block boundary marker board (Repère).

Step-by-Step TVM430 Operation

1.Entering LGV High-Speed Line:Crossing the CAB marker.

1. Pass the CAB trackside board marking the start of LGV territory.

2. Ensure pantograph/voltage selection is set to 25kV AC.

3. The TVM display illuminates with a green 300 or 320 indication.

2.Cruising at 320 km/h:Driving through clear blocks.

1. Throttle up to the indicated green number.

2. As long as the TVM display stays solid green, you have full authority through the current and upcoming blocks.

3.Managing Speed Reductions:Responding to an Exécution block warning.

1. When entering a block that precedes a speed drop or stop, a loud chime sounds and the TVM display changes (e.g., from green 320 to yellow/black 270E).

2. Immediate Action: Shut off the throttle completely (move to 0%) and apply service brakes (PNEU / Rheostatic).

3. Reduce speed continuously so that you drop below 270 km/h before your train crosses the next blue/yellow marker board (Repère).

4.Approaching a Closed Block (000):Bringing the TGV to a complete halt.

1. The TVM steps down through progressive braking blocks: 320 $\rightarrow$ 270E $\rightarrow$ 220E $\rightarrow$ 160E $\rightarrow$ 080E $\rightarrow$ 000.

2. Maintain steady brake pressure throughout each Exécution stage.

3. When 000 appears, bring the train to a complete stop before passing the yellow/blue Nf (Non-franchissable) block marker board at the end of the block.