Complex sentence: This was replaced in 1869 by a chain which operated brakes on all carriages but this could be abrupt, some passengers were injured and it was replaced by a non-automatic vacuum brake by 1876.
Split into simpler sentences: This was replaced in 1869 by a chain which operated brakes on all carriages. The operation of the chain brake could be abrupt, leading to some passenger injuries, and it was replaced by a non-automatic vacuum brake by 1876.