Explanation:

Introduction:
In railway tracks, sleepers play a crucial role in providing support and stability to the rails. They are placed at regular intervals along the track to ensure even distribution of load and to maintain the alignment of the rails. The placement of sleepers is done carefully to ensure the safe and comfortable operation of trains.

Impact of Placing Sleeper below Rail Joint:
Placing a sleeper just below the rail joint can have several negative impacts, which are as follows:

1. More Impact: Placing a sleeper just below the rail joint can result in an increased impact on the joint. The rail joint is the point where two rails are joined together. It is a critical component of the track as it experiences high dynamic loads and stresses when a train passes over it. Placing a sleeper directly below the joint can cause additional stresses and impacts on the joint, leading to premature failure or damage.

2. Discomfort to Passengers: Placing a sleeper just below the rail joint can also result in discomfort to passengers. When a train passes over a sleeper, it creates vibrations and impacts that are transmitted to the passenger compartments. Placing a sleeper directly below the joint can amplify these vibrations and impacts, making the ride more uncomfortable for the passengers.

Correct Answer:
The correct answer to the question is option 'D' - Both 1 and 2.

Conclusion:
Placing a sleeper just below the rail joint can have negative impacts such as increased impact on the joint and discomfort to passengers. Therefore, it is important to follow proper engineering practices and guidelines while designing and constructing railway tracks to ensure the safe and comfortable operation of trains.