Peter Dunn, who last year gave us a subway map based on estimated travel times, has done it again with a time-based commuter-rail map.
Since commuters probably already know their schedules, the diagram is potentially more useful to new riders. Car commuters can see where they might save time by taking the train. Newcomers looking for a place to move in the region can quickly compare how much of their day they'd spend commuting from various stations. (If you choose the home another six minutes away, that's an extra hour a week you'll spend getting to and from work.)