After a long drought of blog posts, some news from last night's MBTA Rider Oversight Committee meeting: According to MBTA officials at the meeting, the completion and re-opening of Copley station will be marked with fanfare at 10:30 this Friday on the eastbound side, adjacent the Boston Public Library. This will also end the first week of three car Green Line train operation since three car trains were silently discontinued in 2005 due to technical issues. Deborah Gies, Green Line manager, on behalf of Brian Dwyer, Director of Light Rail, at last night's MBTA ROC meeting had several Green Line updates, with several notes about metrics for success of three car operation. In particular, the MBTA will be monitoring the number of third car boardings and the ability of the power delivery system to handle the additional load of a third car. To create the three car trains, the MBTA is simply splitting up one train that normally runs between the two scheduled three car trains during rush hour and adding one car from that train to the other two.
With respect to on-time statistics and the new three car trains aimed at tackling reliability and capacity, MBTA ROC co-chair Karen Wepsic noted that it is an ongoing issue that trains are still considered to have completed their journeys 'on time', even if they skip stops in between, as often happens on the E line. Further, Jarret Walker over at humantransit has recently tackled the fundamental issues with on time performance metrics and the realities the riding public actually face:
The explanation, of course, is that peak hour commuter trains are most likely to be late, because they run when the system has the least margin for error. And since most riders of commuter rail are on the peak, most riders experience the system at its least reliable.
In short, 96% on-time performance doesn't mean that 96% of customers get where they're going on time -- only that 96% of trains did, counting nearly empty trains at 10:00 PM when there's plenty of spare capacity on the rails, and a lot fewer causes of delay.
Gies also notes that three car Green Line trains will be coming to the B line in November.