INDIAN RAILWAYS – AUTO – EMERGENCY BRAKING (A.E.B)
AUTO – EMERGENCY BRAKING (A.E.B)
INTRODUCTION
Auto-Emergency Brakes (AEB) refers to a special system of braking employed on Some Ghat section with steep gradients. With steep gradients. With this system, the loco’s speed is limited to 30km/h and the brakes are automatically applied if the loco moves faster than that any time on the AEB Section.
PROCEDURE
The AEB system is activated by means of a key obtained at the top of the descending gradient. The key, which is specific to each loco, is engaged and turned in the loco, and then removed and handed to the guard of the train (except for light locos where there is nor guard). Which the AEB system is activated, the loco cannot run faster than 30km/h the brakes are applied immediately if the speed rises above that.
When the loco reaches the bottom of the down gradient, the AEB system is deactivated and the key is handed over to the station Master of the station at the bottom of the ghat section. From there onwards there onwards, the loco can proceed at normal permissible speeds.
OPERATION
The AEB system depends on a speed sensor attached to the axle generator (Tachometer generator) of the locomotive. The speed sensor controls the Emergency Brake Relay (EBR). The EBR gets energized when the speed sensor detects that the loco is moving faster then 30km/h (or other programmed speed limit).
When the ERB is energized, two emergency brake valves, EBV 1 and EBV 2 get activated. The first emergency brake valve EBV 1 cuts off pilot air from A9 to C2, with the additional C2 relay then causing the Brake pipe to exhaust, while the second emergency brake valve EBV2 also exhausts the Brake pipe pressure and causes application of the brakes.