There's also Breda. But Breda was a very experienced HRT builder (mainstay of the Washington Metro, MARTA, and Miami MetroRail fleets) that belly-flopped trying to get into the modern LRV market. Previous incarnations of the company had done high-floor trams, but umpteen mergers in the 80's and 90's and a 15-year lull between orders had washed out most of their institutional knowledge, so they were starting over. The Type 8's and MUNI LRV2/LRV3's were epic fiascoes, and their similar-era T68/T69's in the UK were trouble-prone oddities retired before their time. Breda was a legitimately much bigger risk for light rail 20 years ago, and the T and MUNI paid dearly for that. I doubt there would've been similar problems if, say, Breda had gotten the Blue Line contract instead because they have such a huge and generally successful worldwide installed base of metro cars that require very little mechanical/electronic customization to fit into different system dimensions. CRRC's worldwide installed base of metro cars is at least as large as Breda's. Theirs just skews to Asia and Middle East instead of Mainland Europe and Southeastern U.S. But HRT is pretty much HRT worldwide, with not a whole lot of wild variety in applications other than signaling tech. So experience is experience and success is success regardless of which continental market it skews to.
SEPTA's commuter rail coach order is the only one that's taking a big risk by going with CRRC, because FRA-compliant domestic rail is a very tough nut to crack. Especially for builders who do more business in Asia where mainline rail is generally lighter-weight than Europe; Euro-derived designs are much easier to adapt to North America than Asian. SEPTA needs MLV-size bi-levels and cabs for the tight (tighter than K-car) clearances of Center City, and unlike the exact clones of the K-car and 8-inch boarding Bombardier BLV tincans that are now on the market from second-source vendors (Rotem for each, but other builders likely to follow) the MLV's patents are still too new to reverse-engineer so CRRC's product is going to be a lot of fresh design. On a small order. That's a big risk for an agency that's had a bad history with risk-taking on custom designs, and has already been burned by a Southeast Asian vendor trying to crack FRA compliance for the first time.
So I would hope if the FCMB pushes out the next CR coach order soon that they aren't so politically over-the-moon to do all their business through CRRC-Springfield because of that big CR maint outsourcing goal of Baker's people. The next bi-level RFP shouldn't be gifted as a big wet kiss for them if Kawasaki happens to submit a competitive bid from their busy Yonkers factory. The T did amend its bid requirements after the Breda and Rotem disasters to provide overrides for builder expertise; per the SEPTA subforum thread SEPTA did not and is still boxed into low-bidder-trumps-all (in this case the runner-up for their bi-levels was Rotem once again). It's one thing to give the order to CRRC if Kawasaki just isn't interested because it's too swamped in Yonkers with MTA orders and bids an unattainable price. In that case they'll have enough years of working history under belt with CRRC and grading CRRC on how faithfully they stick to specs and workmanship on the Orange/Red cars to evaluate their ability to follow the K-car template. But you know for damn sure they're going to underbid again at a loss to go gangbusters at vendor lock-in with the T, so low bid alone can't be what nets them an FRA-compliant order tasked with recovering the fumble from the Brokem +75 car contract option being totally unsuitable. There's real priority on getting someone who's done this before without incident.