Acta Scientiarum Polonorum

The aim of the work is to analyse the specificity of the occurrence of additional works in railway construction
projects currently carried out in Poland. The article presents the key elements of additional works: the definition
of the phenomenon, the factors causing their occurrence, the way of implementing additional works to
the basic contract and the expected consequences of additional works. The most important legal conditions
were discussed, including the amendment to the Public Procurement Law of 22 June 2016. The authors
presented proposals for schemes for reporting additional works in the most common types of investment
implementation depending on the applied contract type.