ACD is a global positioning system (GPS) based device provided in the locomotive which continuously transmits position of loco to other locomotives in the vicinity and applies brakes in a collision-like situation.
Replying to supplementaries during Question Hour, Minister of State for Railways Bharatsinh Solanki said a large number of operational and technical problems had been experienced in trials in southern and Northeast Frontier railways.
"ACD provided by Konkan Railway Corporation Ltd and on trial in Northeast Frontier Railway also has operational problems and technical issues which are yet to be resolved," he said.
There are so many constraints in the ACD that the Railway Ministry is thinking of going in for another system, he said, adding problems such as unwarranted braking have led the ministry to reconsider the project.
"It would be possible to proliferate this system on complicated and High Density Routes on other railways only after these issue are resolved comprehensively by KRCL," he said.
He said collision is the most critical of all rail accidents and new technologies to prevent them include ACD, Train Protection and Warning System (TPWS), Train Collision Avoidance System (TCAS), Vigilance Control Device (VDC) and Fog Safe Device (FSD).