On LA County Supervisor Zev Yaroslavsky's blog: As 2 light rail lines race toward completion, there’s trouble ahead on the tracks. Unless train car production can be significantly accelerated, there won’t be enough vehicles to serve both new lines—Phase 2 of the Expo Line to Santa Monica and the Gold Line Foothill Extension to Azusa—if they open as scheduled in late 2015 and early 2016 respectively.

Metro is so concerned about the problem that it’s dispatching a delegation to the manufacturer’s headquarters in Japan later this month in hopes of finding a way to speed up production—a tall order for a company that the agency acknowledges is on track with the aggressive schedule mutually agreed to under its contract.

So, with a likely initial shortfall of about 50 train cars, the issue presents some tough decisions for Metro, all of which are likely to be unpopular with the traveling public. It could delay the new lines’ openings, operate them with shorter, more crowded trains, offer less frequent service, or redeploy cars from elsewhere in the system, thus spreading the pain more broadly.

The shortage is expected to be most severe in the first months of operation for the two new extensions, with steady improvements coming as new rail cars arrive throughout 2016. But even the prospect of a relatively short-lived disruption has been enough to strain the relationship between Metro, which will operate the lines, and the two construction authorities charged with successfully completing the projects.  Read more.