But, if it’s provided at even a minimal level of service, rail transit can provide decent service over long distances, particularly when not focused on park-and-ride type service but walkable, town-center service (so, generally on older suburbs which developed around rail transit). As important, commuter rail often links smaller cities—and their transit systems—in to the larger system, especially in New York, Boston and Chicago. Rail can provide service that buses can not, because they can operate at relatively high speed, stop in a town center, and then resume their speed without getting bogged down in ten minutes of traffic in each town or having to get on and off highways. The technology of using full train sets may not be ideal—shorter multiple-unit trains would be more economical—but the trains are there, so you might as well use them. 

• Nearly every line with a maximum two-hour-or-better headways has 30-, 60- or 120-minute clock face scheduling. The only exception is the Trinity Railway Express between Dallas and Forth Worth, which runs every 90 minutes. 
• With one exception, lines with better-than-hourly service adhere to clock face scheduling. The exception is the NJ Transit Northeast Corridor Line, which may be constrained by arrival slots in the Hudson River tubes (it does run at least every 38 minutes, however).
• Amongst the major multi-line commuter rail networks (MBTA, SEPTA, METRA, NJT, MN and LIRR) only SEPTA has full hourly service on all lines, most of them operating on a clock-face or partially clock-face schedule (headways get shorter on the shoulders of rush hour, but while 45-minute headways provide more service, it might just confuse passengers and not actually encourage ridership). 
• The New York services have hourly-or-better service on their main lines, but some far-out branches see less service. Most other agencies have some lines with hourly service, and some with less.
• Most hourly services are operated on-or-near clock face, and even two outliers could, with minor changes, be made hourly.
• All METRA lines in Chicago have clock face scheduling, and many the ones which are not hourly have only one two-hour service gap.
• The MBTA, by these metrics, probably has the worst service of any major system. The Lowell Line is the only line with hourly, clock face service; although the Beverly-Boston portion of the combined Newburyport/Rockport lines has a similar level. While several MBTA lines are commuter-oriented, others serve some of the largest cities in the region: Worcester, Fitchburg, Lawrence, Providence and Brockton.