The following steps are involved in laying a sewer in a trench:
1. Transferring the centre line of the sewer to the bottom of the trench.
2. Setting sight rails over the trench.
3. Driving pegs to the level of the invert line of the sewer.
4. Placing the sewer in the trench.
The correct sequence of these steps is
1
1, 2, 3, 4
2
2, 3, 4, 1
3
4, 2, 3, 1
4
2, 3, 1, 4