Those are all questions for which there's no clear answer right now. Though in the light of day with updated news articles it appears that this might be another case of single-double track violation as RT's previous light rail train-on-train wreck (about 25 years ago) was. As with the other wreck, it looks like an in-service train vs. a non-revenue move. Location seems to be near the end of double track going into the single track through the Watt/I-80 parking lots at the northeast end of the line, rather than near the shops as it appeared last night.

RT's signal system is not a true block system as used on subways (one of the reasons they don't have expresses or limited for commuters - would need to build a whole new signal system). It's more like interlocking islands with track in between signaled mainly to hold trains in a station until grade crossings ahead are operating. Even the interlockings mostly operate independently (subject to Dispatch override), based on code transmissions from the trains to identify the required route. Otherwise, VFR. With at least 15-minute headways (except through the downtown area where all 3 lines use the same tracks, at low speed on the street), and with most of the line now double track (single at the ends of the lines, plus a bridge shared with a freeway and a UP underpass), that's more or less OK - unless there'a a train where it shouldn't be (hello, Dispatch?). In this case, going from double into single at the end of the line, there is a signal to hold the northbound train if the single track is occupied - lack of attention on what was probably the last run of the night for that operator? I guess we'll find out more once NTSB gets done with its ruminations. For sure, RT isn't talking and won't be (that's their pattern, and the excuse here will be to not contaminate the NTSB investigation by making public statements).

Looks like Blue Line riders will be on buses for stops past Marconi for a while.