Which of following contract types is usually followed by Railway Department for construction purposes?

lump sum contract: If scope of construction work is well-defined with all its drawings, specification quantities and estimates, then lump sum contract is used.

Percentage rate: Contractor arranges equipment and resources which paid by owner with certain percentage of construction(say 15%).

Item rate contract: contractors are required to quote rates for individual items of work on the basis of the schedule of quantities furnished by the client’s department. Indian Railways and many Public Sector units use this method of contracts.

Piece work: Contractor are paid with fixed piece rate of certain item.