Non-Leading (NL)
European Railway Agency
ETCS Driver's handbook

Non-Leading (NL)

NL.1The Non-Leading (NL) mode is used to manage the ETCS on-board equipment of a slave engine that is not electrically coupled to the leading engine (and so, not remote controlled) but has its own driver. This operating situation is called tandem.

During a tandem movement, only the leading engine is responsible for the train movement supervision functions.

The train speed is always presented to the driver. The driver is responsible for fulfilling the orders associated to track conditions, when they are displayed on the DMI.

NL.2To enter NL mode and perform a tandem movement, the driver of the Non-Leading engine shall select the Non-Leading option in the Main window of the DMI with the train at standstill.

NL-[L0N1.T].1To access the Main window, the driver of the Non-Leading engine shall press the button on the Default window of the DMI as indicated in Figure MAIN-[L0N1.T].F2.

Figure MAIN-[L0N1.T].F2: Main button on Default window (touch screen technology)

NL-[L2.T].1To access the Main window, the driver of the Non-Leading engine shall press the button on the Default window of the DMI as indicated in Figure MAIN-[L2.T].F2.

Figure MAIN-[L2.T].F2: Main button on Default window (touch screen technology)

NL-[L0N1.S].1To access the Main window, the driver of the Non-Leading engine shall press the button on the Default window of the DMI as indicated in Figure MAIN-[L0N1.S].F2.

Figure MAIN-[L0N1.S].F2: Main button on Default window (soft key technology)

NL-[L2.S].1To access the Main window, the driver of the Non-Leading engine shall press the button on the Default window of the DMI as indicated in Figure MAIN-[L2.S].F2.

Figure MAIN-[L2.S].F2: Main button on Default window (soft key technology)

NL.3As a result, the Main window is presented to the driver.

NL-[B3241.L0N1.T].2The driver of the Non-Leading engine shall then select the button as indicated in Figure NL-[B3241.L0N1.T].F2.

Figure NL-[B3241.L0N1.T].F2: Non-Leading button on Main window (touch screen technology)

NL-[B3241.L2.T].2The driver of the Non-Leading engine shall then select the button as indicated in Figure NL-[B3241.L2.T].F2.

Figure NL-[B3241.L2.T].F2: Non-Leading button on Main window (touch screen technology)

NL-[B3241.L0N1.S].2The driver of the Non-Leading engine shall then select the button associated to the Non-Leading label as indicated in Figure NL-[B3241.L0N1.S].F2.

Figure NL-[B3241.L0N1.S].F2: Non-Leading button on Main window (soft key technology)

NL-[B3241.L2.S].2The driver of the Non-Leading engine shall then select the button associated to the Non-Leading label as indicated in Figure NL-[B3241.L2.S].F2.

Figure NL-[B3241.L2.S].F2: Non-Leading button on Main window (soft key technology)

NL-[B3M1.L0N1.T].1The driver of the Non-Leading engine shall then select the button as indicated in Figure NL-[B3M1.L0N1.T].F1.

Figure NL-[B3M1.L0N1.T].F1: Non-Leading button on Main window (touch screen technology)

NL-[B3M1.L23.T].1The driver of the Non-Leading engine shall then select the button as indicated in Figure NL-[B3M1.L23.T].F1.

Figure NL-[B3M1.L23.T].F1: Non-Leading button on Main window (touch screen technology)

NL-[B3M1.L0N1.S].1The driver of the Non-Leading engine shall then select the button associated to the Non-Leading label as indicated in Figure NL-[B3M1.L0N1.S].F1.

Figure NL-[B3M1.L0N1.S].F1: Non-Leading button on Main window (soft key technology)

NL-[B3M1.L23.S].1The driver of the Non-Leading engine shall then select the button associated to the Non-Leading label as indicated in Figure NL-[B3M1.L23.S].F1.

Figure NL-[B3M1.L23.S].F1: Non-Leading button on Main window (soft key technology)

NL.4The button is a delay-type button, meaning that the driver must keep pressing during 2 seconds to be considered by the DMI. If the button is pressed by the driver for less than the 2 seconds, no valid request to enter Non-Leading mode shall be considered by the onboard.

NL-[112021].1The button is enabled to change to NL mode when the following conditions are fulfilled:

  1. The train is at standstill AND,
  2. The mode is SB/SH/FS/LS/SR/OS AND,
  3. The Driver ID, ERTMS/ETCS level are valid AND,
  4. The Non-Leading input signal is received (brakes isolated AND travel direction selected).

The non-leading input is received either if the travel direction is selected AND either:

  1. the brake release function of the train wide brake control device of the engine is inhibited (for example in case the driver of the non-leading engine is allowed to command the service brake application) OR,
  2. the train wide service brake control device of the engine is isolated (for example it is isolated from the brake pipe, in case of using a brake pipe pressure control system).

If none of the conditions is fulfilled, the non-leading input shall have the value “Non-leading not permitted”.

NL-[22].1The button is enabled to change to NL mode when the following conditions are fulfilled:

  1. The train is at standstill AND,
  2. The mode is SB/SH/FS/AD/LS/SR/OS AND,
  3. The Driver ID, ERTMS/ETCS level are valid AND,
  4. The Non-Leading input signal is received (brakes isolated AND travel direction selected).

The non-leading input is received either if the travel direction is selected AND either:

  1. the brake release function of the train wide brake control device of the engine is inhibited (for example in case the driver of the non-leading engine is allowed to command the service brake application) OR,
  2. the train wide service brake control device of the engine is isolated (for example it is isolated from the brake pipe, in case of using a brake pipe pressure control system).

If none of the conditions is fulfilled, the non-leading input shall have the value “Non-leading not permitted”.

NL-[30].1The button is enabled to change to NL mode when the following conditions are fulfilled:

  1. The train is at standstill AND,
  2. The mode is SB/SH/FS/AD/SM/LS/SR/OS AND,
  3. The Driver ID, ERTMS/ETCS level are valid AND,
  4. The Non-Leading input signal is received (brakes isolated AND travel direction selected).

The non-leading input is received either if:

  1. the brake release function of the train wide brake control device of the engine is inhibited (for example in case the driver of the non-leading engine is allowed to command the service brake application) OR,
  2. the train wide service brake control device of the engine is isolated (for example it is isolated from the brake pipe, in case of using a brake pipe pressure control system).

If none of the conditions is fulfilled, the non-leading input shall have the value “Non-leading not permitted”.

NL.5Once the Non-Leading button is selected, the Main window is replaced by the default screen.

When the entry into NL is achieved and the Non-Leading symbol (MO12, located in area B7) is displayed on the DMI, the driver of the Non-Leading traction unit shall confirm to the driver of the leading engine that the Non-Leading traction unit is in NL mode.

MO12: Non-Leading

NL-[2230].1If an ATO communication session is ongoing, ATO-OB shall terminate the communication session with a given ATO-TS when ETCS-OB enters in NL Mode.

NL.6To exit from NL mode when the train is at standstill, the driver of the Non-Leading engine shall:

  1. Apply the brakes,
  2. Confirm to the driver of the leading engine that the Non-Leading traction unit is not any more in NL.

When the driver applies the brakes, the non-leading input signal is not received any more, and consequently the transition to SB is triggered (see section SB - Stand-By (SB)).

Video: NL movement in level 1 (touch screen technology)

Video: NL movement in level 1 (soft key technology)

Video: NL movement in level 2 (touch screen technology)

Video: NL movement in level 2 (soft key technology)

NL.7Additionally to the transition mentioned previously (i.e. NL → SB, when the non-leading input signal is not received), the following mode transitions can be triggered from NL mode:

  1. NP mode. Transition triggered when the ETCS on-board is powered off as indicated in section OFF.PWR Power off the ETCS on-board (PWR).
  2. SB mode. Transition triggered when the desk is closed as indicated in section OFF.CLS Close the desk (CLS).
  3. IS mode. Transition triggered when the driver isolates the ETCS on-board equipment (see section IS.ENT Entering Isolation mode (ENT)).

NL-[30].2Upon the detection that the non-leading input information is set to Non-leading not permitted, the DMI shall display the text message "NL no longer permitted" and shall request an acknowledgement from the driver. However, the switch to Stand-By mode shall be made only if the train is at standstill.