Many undergraduate engineering programs require senior students to take capstone design courses to work on industry-sponsored projects. Such a project often involves multiple parties of people playing various roles: students as project workers, faculty members as coordinator or advisors, as well as mentors from the sponsoring industry. In order to promote student success, highly demanded are platforms that can effectively facilitate multi-party collaboration during the development process of capstone projects. CapStone is such a platform that has been developed and deployed at the Behrend College, Pennsylvania State University. In this paper, we present the design rationale of CapStone, explaining the responsibilities of different roles involved in a capstone project and how those responsibilities are meshed into one common platform such that all parties could effectively orchestrate their activities. We have also conducted a study on how well CapStone could help student users in their project development. The responses showed that the adoption of CapStone has significantly improved student success in many ways. Particularly, over 80% of the students found CapStone helpful in project planning/scheduling, reporting weekly progress to advisors, collecting feedbacks on project works, and in writing their project reports.