Yeah we'd need to buy more trains, and that was always the plan. No point in buying more trains than we need and have many just laying around doing nothing most days. We currently have 34, and we're getting 4 more between stage 1 and 2 to address potentially capacity issue the could crop up between when they get ramping up stage 2 vehicle production. Buying i think 38 LRVs with stage 2 (for a total of 76 if i'm remembering right) and that's for the increased track length to maintain the 5 minutes or less frequency during rush over, and some to add more total capacity (aka just having more trains on the line). the trains themselves can have a total of 5 module per vehicle (we're starting with 4).
I believe we're starting with somewhere between 11-12 thousand PPDPH (transitway does a bit of 10 right now), and the max of the line, including the 5th modules and 90 minute frequency is about 24.