Maximum impact speed when shunting a group of roller bearing fitted stock coupled together must be? A. 2 kmph B. 2.5 kmph C. 3 kmph D. 3.5 kmph

The correct answer is B. 2.5 kmph.

The maximum impact speed when shunting a group of roller bearing fitted stock coupled together must be 2.5 kmph. This is to ensure that the couplings between the wagons do not break and that the wagons do not derail.

Option A is incorrect because it is too low. The wagons may not be able to couple properly if the impact speed is too low.

Option C is incorrect because it is too high. The wagons may derail if the impact speed is too high.

Option D is incorrect because it is not a valid option.