Concept:Rail transport faces several operational and technical challenges in developing countries. A major limitation is the shortage of skilled personnel and maintenance capacity.
Explanation:Rail systems require specialised engineers, technicians, and managers to operate and maintain them.
Many developing countries do not have enough trained personnel to run modern rail networks effectively.
This lack of technical know-how leads to poor maintenance, frequent breakdowns, and unreliable services.
In contrast, the other options describe advantages, not limitations: construction and maintenance are often costly, and rail transport is not considered too fast.
Answer:A. Lack of technical know-how