Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 14 2 2022 09 30 157 163 Melody Khadem Sameni Iran University of Science and Technology Maryam Sadat Ghaem Maghami Iran University of Science and Technology Hassan Sadeghi Naeini Iran University of Science and Technology 2021 09 01 2022 08 31 In developing countries that still use conventional trains, passengers spend lengthy hours on board while they can have the option of choosing air travel with much shorter duration. Hence environmental factors play an important role in overall comfort of passengers and modal share of railways. In this cross-sectioned research, a questionnaire is developed that quantifies evaluations of passengers from factors such as light, temperature, noise and vibrations. An 11-hour journey between Tehran, the capital of Iran, and the second major city and two trains (five-star and four-star) are selected. Passengers responded to paper questionnaires and 382 fully filled ones were collected and analyzed. Satisfaction from light was highest and thermal comfort was lowest. There was statistically significant difference between comfort of passengers at two trains. The results also showed that some personal or health conditions affect feelings of passengers. For instance, those who suffer from low blood pressure feel cold or those that wear glasses for reading are not satisfied with illumination. Moreover, the elderly are more sensitive to vibrations but those who travel with their families are less sensitive to it. The results of this research can help in better allocation of compartments to passengers and increasing overall passenger satisfaction.  https://ijoh.tums.ac.ir/index.php/ijoh/article/view/537