On Sight (OS)
European Railway Agency
ETCS Driver's handbook

On Sight (OS)

OS.APPApproaching an OS area (APP)

OS.APP-[L12].1When the train is approaching an OS area, the Acknowledgement for On Sight mode symbol (MO08) is displayed. The driver shall acknowledge the OS mode as indicated in following section OS.ACK Acknowledge of OS mode (ACK).

MO08: Acknowledgement for On Sight mode

If the OS mode is requested for the current location, the transition to OS mode is performed immediately and the Acknowledgement for On Sight mode symbol (MO08) is displayed.

OS.ACKAcknowledge of OS mode (ACK)

OS.ACK-[L12.N].1When the Acknowledgement for On Sight mode symbol (MO08) is displayed, the driver shall:

  1. Acknowledge,
  2. Start or continue running on sight, meaning:
    • Proceed with caution, controlling the speed having regard to the visibility of the line ahead, so that it is possible within the free visible part to stop short of any vehicle, stop aspect or obstacle on the infrastructure; and
    • Not exceed the maximum speed for running on sight.

OS.ACK-[L1.T].1To acknowledge the OS mode, the driver shall press the button as indicated in Figure OS.ACK-[L1.T].F1.

Figure OS.ACK-[L1.T].F1: Acknowledgement for On Sight mode button (touch screen technology)

OS.ACK-[L2.T].1To acknowledge the OS mode, the driver shall press the button as indicated in Figure OS.ACK-[L2.T].F1.

Figure OS.ACK-[L2.T].F1: Acknowledgement for On Sight mode button (touch screen technology)

OS.ACK-[L1.S].1To acknowledge the OS mode, the driver shall press the button with a flashing frame associated to the MO08 symbol as indicated in Figure OS.ACK-[L1.S].F1.

Figure OS.ACK-[L1.S].F1: Acknowledgement for On Sight mode button (soft key technology)

OS.ACK-[L2.S].1To acknowledge the OS mode, the driver shall press the button with a flashing frame associated to the MO08 symbol as indicated in Figure OS.ACK-[L2.S].F1.

Figure OS.ACK-[L2.S].F1: Acknowledgement for On Sight mode button (soft key technology)

OS.ACK-[L12].1When the driver acknowledges or the train reaches the beginning of the On Sight area, the mode changes to OS mode.

OS.ACK-[L12].2Once inside the On Sight area, if the driver has not acknowledged the transition to OS mode within 5 seconds after the change to OS mode, the service brake command is triggered.

The brake command is released when the driver acknowledges the change to OS mode, unless the command was triggered for another reason.

OS.ACK-[L12].3If when entering the OS mode, the train speed was higher than the OS mode speed limit the brake could be immediately triggered, independently of the acknowledgement of the driver.

Video: Entry in OS in level 1 (touch screen technology)

Video: Entry in OS in level 1 (soft key technology)

Video: Entry in OS in level 2 (touch screen technology)

Video: Entry in OS in level 2 (soft key technology)

OS.RUNRunning in OS (RUN)

OS.RUN-[L12.N].1When On Sight mode is active, the On Sight symbol (MO07) is displayed.

MO07: On Sight mode active

The driver shall:

  1. Run on sight,
  2. Not exceed the permitted speed determined by a National Value,
  3. Proceed with caution, controlling the speed having regard to the visibility of the line ahead, so that it is possible within the free visible part to stop short of any vehicle, stop aspect or obstacle on the infrastructure.

This does not apply to unexpected obstacle entering the track zone within the stopping distance.

The driver shall comply with speed restrictions lower than the permitted speed indicated on the DMI. The driver is informed by the signaller or by a dedicated document or computer about these speed limitations.

OS.RUN-[L12].1The driver is responsible for checking the track occupancy when moving the train because the track may be occupied.

OS.RUN-[L12].2The driver shall enter the Track ahead free information if requested as indicated in section OTH.TAF Track Ahead Free (TAF)).

OS.RUN-[L12].3If the message “Entering OS” is displayed, the driver shall not exceed the speed restrictions.

OS.RUN-[B3241.L1.T].1The permitted speed, target distance, target speed, release speed (if any) and planning information are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by pressing the area indicated in Figure OS.RUN-[B3241.L1.T].F1.

Figure OS.RUN-[B3241.L1.T].F1: Toggling on and off area (touch screen technology)

OS.RUN-[B3241.L2.T].1The permitted speed, target distance, target speed, release speed (if any) and planning information are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by pressing the area indicated in Figure OS.RUN-[B3241.L2.T].F1.

Figure OS.RUN-[B3241.L2.T].F1: Toggling on and off area (touch screen technology)

OS.RUN-[B3241.L1.S].1The permitted speed, target distance, target speed, release speed (if any) and planning information are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by selecting the button as indicated in Figure OS.RUN-[B3241.L1.S].F1.

Figure OS.RUN-[B3241.L1.S].F1: Toggling on and off button (soft key technology)

OS.RUN-[B3241.L2.S].1The permitted speed, target distance, target speed, release speed (if any) and planning information are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by selecting the button as indicated in Figure OS.RUN-[B3241.L2.S].F1.

Figure OS.RUN-[B3241.L2.S].F1: Toggling on and off button (soft key technology)

OS.RUN-[B3M1.L1.T].1The permitted speed, target distance, target speed and release speed (if any) are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by pressing the area indicated in Figure OS.RUN-[B3M1.L1.T].F1.

Figure OS.RUN-[B3M1.L1.T].F1: Toggling on and off area (touch screen technology)

OS.RUN-[B3M1.L23.T].1The permitted speed, target distance, target speed and release speed (if any) are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by pressing the area indicated in Figure OS.RUN-[B3M1.L23.T].F1.

Figure OS.RUN-[B3M1.L23.T].F1: Toggling on and off area (touch screen technology)

OS.RUN-[B3M1.L1.S].1The permitted speed, target distance, target speed and release speed (if any) are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by selecting the button as indicated in Figure OS.RUN-[B3M1.L1.S].F1.

Figure OS.RUN-[B3M1.L1.S].F1: Toggling on and off button (soft key technology)

OS.RUN-[B3M1.L23.S].1The permitted speed, target distance, target speed and release speed (if any) are not shown by default on the DMI. The driver can toggle on and off the display of these parameters by selecting the button as indicated in Figure OS.RUN-[B3M1.L23.S].F1.

Figure OS.RUN-[B3M1.L23.S].F1: Toggling on and off button (soft key technology)

OS.RUN-[B3241.L1.T].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3241.L1.T].F2. The release speed, target distance and planning information are shown as in the other modes.

Figure OS.RUN-[B3241.L1.T].F2: Permitted speed, target speed, release speed, target distance and planning information in OS mode (touch screen technology)

OS.RUN-[B3241.L2.T].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3241.L2.T].F2. The release speed, target distance and planning information are shown as in the other modes.

Figure OS.RUN-[B3241.L2.T].F2: Permitted speed, target speed, release speed, target distance and planning information in OS mode (touch screen technology)

OS.RUN-[B3241.L1.S].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3241.L1.S].F2. The release speed, target distance and planning information are shown as in the other modes.

Figure OS.RUN-[B3241.L1.S].F2: Permitted speed, target speed, release speed, target distance and planning information in OS mode (soft key technology)

OS.RUN-[B3241.L2.S].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3241.L2.S].F2. The release speed, target distance and planning information are shown as in the other modes.

Figure OS.RUN-[B3241.L2.S].F2: Permitted speed, target speed, release speed, target distance and planning information in OS mode (soft key technology)

OS.RUN-[B3M1.L1.T].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3M1.L1.T].F2. The release speed and target distance are shown as in the other modes.

Figure OS.RUN-[B3M1.L1.T].F2: Permitted speed, target speed, release speed and target distance in OS mode (touch screen technology)

OS.RUN-[B3M1.L23.T].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3M1.L23.T].F2. The release speed and target distance are shown as in the other modes.

Figure OS.RUN-[B3M1.L23.T].F2: Permitted speed, target speed, release speed and target distance in OS mode (touch screen technology)

OS.RUN-[B3M1.L1.S].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3M1.L1.S].F2. The release speed and target distance are shown as in the other modes.

Figure OS.RUN-[B3M1.L1.S].F2: Permitted speed, target speed, release speed and target distance in OS mode (soft key technology)

OS.RUN-[B3M1.L23.S].2The permitted speed is shown as a white hook and the target speed as a grey hook as indicated in Figure OS.RUN-[B3M1.L23.S].F2. The release speed and target distance are shown as in the other modes.

Figure OS.RUN-[B3M1.L23.S].F2: Permitted speed, target speed, release speed and target distance in OS mode (soft key technology)

OS.RUN-[L12].4The OS mode is exited when the front end of train passes the end of the OS area.

OS.RUN-[L12].5The following mode transitions can be triggered from OS 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. SH mode. Transition initiated either manually by the Driver (see section SH.MAN Manual entry into SH (MAN)) or automatically by an order from the Trackside (see section SH.AUT Automatic entry into SH (AUT)).
  4. FS mode. Transition usually initiated by order from the Trackside (see section FS.RUN Running in FS (RUN)).
  5. LS mode. Transition automatically initiated by an order from the Trackside (see section LS.APP Approaching an LS area (APP)).
  6. SR mode. Transition manually initiated by the Driver when override (see section OVR.RUL Rules to pass an EOA (RUL)).
  7. NL mode. Transition manually initiated by the Driver (see section NL - Non-Leading (NL)).
  8. UN mode. Transition usually initiated by an order from the Trackside (see section UN - Unfitted (UN)). This transition also includes a transition of level initiated either manually by the Driver (see section LTR.TRS.DRV Level transition initiated by driver (DRV)) or ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
  9. TR mode. Transition automatically initiated by an order from the Trackside (see section see section TR - Trip / Post Trip (TR)).
  10. SF mode. Automatic transition triggered in case of a fault (see section SF - System Failure (SF)).
  11. IS mode. Transition triggered when the driver isolates the ETCS on-board equipment (see section IS.ENT Entering Isolation mode (ENT)).
  12. SN mode. Transition usually initiated by an order from the Trackside (see section SN - National System (SN)). This transition also includes a transition of level either initiated manually by the Driver (see section LTR.TRS.DRV Level transition initiated by driver (DRV)) or ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
  13. RV mode. Transition initiated after the driver´s acknowledgement of the RV mode as indicated in section RV.ENT Entry in RV mode (ENT).
  14. SM mode. Transition initiated manually by the Driver, see section SM.ENT Entry into SM (ENT).

OS.RUN-[L2].1If, while being in release speed monitoring, the on-board receives a balise group whose first possible location is known by linking information to be in rear of the EOA by a distance shorter than the distance between the active Eurobalise antenna and the front end of the train, at the EOA or in advance of the EOA and ERTMS/ETCS level is 2, the train changes to Trip mode, see section TR - Trip / Post Trip (TR).

OS.RUN-[L12.2330].1If the valid Train Data is stored on-board and the safe consist length in front the engine becomes different from zero the transition to SB is triggered (see section SB - Stand-By (SB)).