Railway Direction Indicator :- •Direction Indicator is a display along the track side at critical locations that informs the train operator of direction of the path ahead.
• This indicators display a text sign based on a command the system management center. The text will indicate the next route as being a mainline move or a depot/shunt move. However they do not indicate that the approaching train has been authorized to proceed along the indicated route.
• Direction Indicators will be provided at locations in which a non- passenger move and a passenger move may be made and at branches.
• Direction Indicator is a display provided at facing points where there is a move for which it is necessary, for operational purpose, to indicate the route to be taken to the train operator.
• The SMC will provide the route information via the PLC non-vital outputs to the DI in order for it to illuminate.
• The SMC will remove the output indication to the direction indicator when the train has been reported as having passed the direction indicator.
• It is visible to the train operator when the train is stationary.
• The aspect displayed shall be Lunar white.
• Mixed Mode Area: At locations where a Direction Indicator is required, and there is a shunt signal(or) main signal required for Metropolitan line trains, both will be provided. This is to give consistent operational instructions to TBTC train driver regardless of location.
• The applicable DI will be blanked if the next destination on a SMC route assignment passes through a SCS region where the SCS is operating in DMC or LCP mode.
• All the DIs associated with a VCC will be blanked if the communication between the VCC and SMC is severed.
• When RS sign is illuminated, then DIs will not be lit, If the RS and DI are located in the same post.
Two series of DI units are required, they are
1. Open section and
2. Tunnel section.
DI Symbol shown in SSP: