The objective of this study was twofold: (a) to determine the extent to which three types of instruction could improve writing performance of railway engineering students and (b) to explore students' perceptions of flipped classroom, Edmodo, and Google Docs for improving their academic writing performance. The participants were 61 undergraduate students of railway engineering at Iran University of Science and Technology (IUST), who were divided into integrated flipped, conventional flipped, and traditional non-flipped groups. For the integrated flipped group, the inquiry-based learning was conducted in terms of five phases of orientation, conceptualization, investigation, data interpretation, and conclusion. They also used Edmodo and Google Docs as the two collaborative platforms for promoting writing skills. The conventional group only watched the instructional videos before the class, while for the traditional group neither the instructional videos nor the technological tools were used for improving their writing skills. The results of ANOVA revealed significant differences among the three groups in that learners in the integrated flipped group significantly outperformed those in the other groups, particularly in terms of the components of grammar and fluency. In addition, this approach made the learners more engaged, motivated, satisfied, and less anxious. The results also showed learners' positive attitudes toward the pedagogical values of Edmodo and Google Docs.