Commute-a-holic and I have both noticed that the Boston Metro has periodically run a Q&A with MBTA GM Dan Grabauskas. The most recent Q&A was published on Monday, March 10th.
A Boston Metro reader wrote in about the discrepancy between actual on-time arrivals for the Newburyport-Rockport line and "published" arrival times listed at North Station. Read Dan's answer - can the man ever answer a question and assume responsibility instead of passing blame?
The information at North Station is posted by MBCR as one of their efforts to update customers of on-time performance on Commuter Rail lines. The on-time performance percentages on these posters are reflective of the total number of trains operated on a service line in comparison to all service delays of five minutes or greater.
As you have noted, the total on-time performance for a line will be higher on average than the on-time performance during peak periods. It is also important to note that the peak period on-time performance may vary significantly for the on-time performance for each train within that peak period.
Using the Newburyport Line as the example, please note the following: A total of 868 trains were scheduled to operate in February, 2008. Of these trains, 140 (16.1 percent) were scheduled in the a.m. peak period, 120 (13.8 percent) in the p.m. peak period, 500 (57.6 percent) in the daily non-peak period, and 108 (12.4 percent) on weekends and holidays. For those trains scheduled in the a.m. peak period, 118 arrived at their final destination on-time or within five minutes of their scheduled arrival, resulting in an on-time performance of 84.3 percent. In the p.m. peak period, 85 of the scheduled trains in this time period arrived on time with an on-time performance of 70.8 percent. For the largest block of trains, the 500 non-peak daily trains, 441 arrived on schedule, resulting in an on-time performance of 88.2 percent. Finally, 92 of the 108 weekend trains arrived on time for an on-time performance of 85.2 percent. Add these totals together and the result is that 868 trains were scheduled in February, of which 736 arrived on schedule with an on-time performance for the month of 84.8 percent. This is an increase in on-time performance of nearly 10 percent over the month of January (75.1 percent).
In presenting the data for February, the posters displaying information will show on-time performance for the Newburyport Line of 84.8 percent and 85.3 percent for the Rockport Line. In the a.m. peak period (which you specifically inquired about), on-time performance on the Newburyport Line was 84.3 percent and 75 percent on the Rockport Line.
While monitoring on-time performance for every train is a priority for the MBTA, the statistics posted at North Station are reflective of the overall service. And although the on-time performance rates have been trending in a positive direction recently, the MBTA and MBCR are strongly determined to lift these rates to higher and higher levels.