DepartureVision

Disclaimer: the contents of this article are based solely on an outsider’s analysis of how DepartureVision works. We will happily correct this story should better information come to light.

DepartureVision – along with its half-brothers MyBusNow and MyLightRailNow – is one of the most useful tools added to the NJ Transit website and mobile site in recent memory. It provides real-time train information in the form of a departure board, including a countdown timer if the train is en route and operating normally. It does have some limitations, however, and we believe the tool is much more useful if you understand them.

Garbage In, Garbage Out

The first thing to keep in mind is that the system is only as good as the data it’s receiving. The system appears to have three sources of data: the day’s preprogrammed schedule, each train’s GPS unit and information from the operations center. Each of these data sources is a point of failure, and any of them can prevent DepartureVision from giving accurate information. If the system doesn’t have enough information to track a train in real time, it falls back to being a glorified schedule-board (more on that later).

Its most serious weakness is that there are certain things the system can’t determine automatically: whether a train has been canceled, for example, or what specific train a particular set of equipment is running on. It is reliant on a human entering that data completely and accurately. As a result, cancelations may not show up in the early morning or late at night, when the people handling that aren’t on duty. Occasionally cancelations at other times of day may be missed by staff and not reported, something we sincerely hope is a rare occurrence. Likewise, if the equipment that will become your train isn’t available at its departure time for some reason, the system probably won’t know that until either the equipment eventually arrives or a different train-set is assigned to your train – basically, until someone with a pulse tells the system that cab car 7023 will be running as train 6628.   

A second source of trouble is the hardware on the trains themselves – if the train isn’t transmitting its location back to base for some reason, DepartureVision has no way of knowing where it is. The third issue is that the system assumes there won’t be a major deviation from schedule. For example, if an inner-zone local (say to Summit) is canceled and combined with an outer zone express (eg. to Dover), DepartureVision won’t know that the train is making extra stops, and the train won’t appear on the screens for those stations.

 

Knowing the Signs

There’s a simple 3-step test to determine if DepartureVision doesn’t know where your train is. This trick won’t work for the train’s origin, but can be used for any intermediate station. Check DepartureVision 5 minutes before your train’s scheduled departure. If no status or arrival time countdown is shown, this hints at the possibility. To confirm, check the page at the train’s scheduled departure time and a minute or so after. If the status was “All Aboard” on the former and the train isn’t shown on the latter, DepartureVision doesn’t know where your train is and inaccurately showed the train leaving on schedule. Note that DepartureVision may self-correct and show the train again if it gets the train’s location later, but you’re probably better off looking to other sources of information at that point.

As far as unreported cancelations go, the best thing you can do is keep your ears open. Assuming someone is on duty at the time, there may be human-delivered announcements that indicate a cancelation or a major line-wide service disruption. DepartureVision may still be able to show you alternative train options if it has complete information on them – as in the case above, look for countdowns as an indication of trains it knows about.

DeparureVision can be accessed from a button on the mobile site, http://m.njtransit.com , or from a box immediately below the central news-carousel on the desktop website, http://www.njtransit.com.