One of the HR from Alstom called for this requirement by looking at my profile in Job portal. Explained over the phone about the requirement. Scheduled for a first technical interview. It took almost 90 minutes and then met with Director, he described about company and expectation from candidate. No calls for 2 weeks. Later called for one more technical interview followed by HR interview. It took almost month to get offer. Interview was pretty simple. Asked basics of C, C++, Multithreading ,RTOS concepts, Python.