عنوان مقاله [English]
Around the world, delays are a common and common issue for the employer, consultant or contractor in any project . The causes for delays in large railway projects are very complex given the characteristics of the whole project area . Delays in projects impose a lot of costs on the employer and the contractor, so identifying the causes of delays and ranking them can be a great help for the success of other projects . In this article, various researches in the field of factors affecting the incidence Delays in rail and transportation construction projects have been investigated, and key factors in delays in construction projects have been identified from four sources: employer, contractor, consultant, and others. In most studies, the method of collecting field information was a structured questionnaire and interviews with a survey approach. To find English articles ̒Google Scholar̓ and Persian articles were used from ̒civilica̓ database. In this study, in addition to domestic articles on the causes of delays in the country's railway and construction projects, foreign articles on the causes and delays railway projects in Malaysia, Ethiopia, Saudi Arabia, China and Korea were used. Finally, it was found that 100% of railway construction projects have suffered from time delays and the most important cause of delays in projects has been the lack of funding and timely payment of funds to the contractor and lack of proper planning.