New signs are in place at stations along the Silver Line. (Robert Thomson/The Washington Post)

With all the changes in the schedules on the Orange, Blue and Yellow lines, and the addition Saturday of the Silver Line, Metro riders have many new reasons to check the online transit scheduler called Trip Planner. Most often, this works well, but there are some things to know about navigating Metro’s navigator.

Results vary. Metro divides the day into big blocks of time, during which the trains are scheduled to run at a certain pace. On the Metrorail Frequency page on the transit authority Web site, the blocks of time are defined this way:

  • AM Rush: approximately 5 – 9:30 a.m.
  • Midday: approximately 9:30 a.m. – 3 p.m.
  • PM Rush: approximately 3 – 7 p.m.
  • Evening: approximately 7 – 9:30 p.m.
  • Late Night: approximately 9:30 p.m. – close

They sure say “approximately” a lot.

On all lines but the Red Line, the Metrorail Frequency page says, trains are scheduled to operate at six-minute intervals. As of this week, Blue Line riders know how “approximately” that is, since their trains are now scheduled to operate every 12 minutes. They will be checking Trip Planner in an attempt to minimize their platform waits, or to figure out if it’s worth taking the Yellow Line instead, and then transferring trains at L’Enfant Plaza.

Riders on other lines also will be looking for specific travel patterns within those big blocks of time, but let’s start with a Blue Line example.

A rider who travels from King Street to Metro Center might ask Trip Planner about trains leaving after 7 a.m. Monday. Trip Planner will advise that there’s a Blue Line train scheduled for 7 a.m., then another one at 7:12 a.m. But in between, at 7:05 a.m., there’s a Yellow Line train, which the rider could take to L’Enfant Plaza and then switch to a westbound Silver Line train to Metro Center. That trip is scheduled to take 25 minutes, just one minute longer than the Blue Line trips. But note that you need to step lively to make that Yellow/Silver transfer work. On the schedule, you’ve got three minutes to get exit the Yellow Line train and reach the Silver Line platform. It wouldn’t take much of a delay on the Yellow Line for you to miss the connection at L’Enfant Plaza, though at that hour, it’s not a long wait for the next westbound train.

Trip Planner is set up to show you three itineraries, and one of them might include a variation, like that Yellow/Silver Line trip.

How about we go from Franconia-Springfield to Foggy Bottom after 8 a.m.? No creative variable there. This is the Blue Line riders’ frustration with the cutbacks that took effect this week. Trip Planner gives you Blue Line trains leaving at 8 o’clock, 8:12 and 8:24 a.m. No chance for creativity here. Foggy Bottom is just too far from L’Enfant Plaza for the transfer strategy to make any sense.

Or is it? What if I tell Trip Planner that I’m going to board at Crystal City at 7 a.m. Monday for that trip to Foggy Bottom? Well, then it tells me I can get a Blue Line train at 7:09 or 7:21 — or, I can board a Yellow Line train at 7 a.m., transfer to a Blue Line train at L’Enfant Plaza and ride to Foggy Bottom for a total trip time of 20 minutes. You would arrive at Foggy Bottom at 7:20, same scheduled time of arrival as that Blue Line train that left Crystal City at 7:09.

Sometimes, Trip Planner gets a little too creative. Say you want the Early Bird Special on the Silver Line, leaving the Wiehle-Reston East station after 5:15 a.m. You will discover that the first train after that time leaves at 5:29, and the one after that at 5:41, an early morning gap of 12 minutes, indicating the ramp-up time before the frequency peaks at six minutes between trains.

But Trip Planner also offers you a third option: Get off that 5:29 Silver Line at East Falls Church and wait on the platform for an Orange Line train to Metro Center. That is indeed original, but why would anyone give up a Silver Line seat to wait on the same platform for an inbound Orange Line train? So you can get out and stretch your legs on the East Falls Church platform, or visit the platform cafe, before continuing your journey to Metro Center?

Okay, I can think of one reason — maybe. Perhaps your Silver Line train is jammed. It could happen, though probably not at 5:29 a.m. But it’s possible you might want to get off a crowded train at East Falls Church and take your chances with the next Orange Line train coming in from Vienna. (I wouldn’t, unless experience shows us that those Vienna trains become much less crowded after the Silver Line opens.)

Bottom line: This is the biggest change in transit scheduling in many years. Checking Trip Planner for the new scheduling details is worth it, as long as you know what you’re looking at. And that includes knowing that the precise schedule almost never holds up throughout a rush hour, even when the train service is operating normally. That’s an especially important factor to remember if your trip includes a transfer. (The schedule then has two chances to be wrong.)

A backup: Sign up for MetroAlerts, Metro’s e-mail and text notifications about schedule changes. Or check for Metro’s Twitter updates on @metrorailinfo.

See related: Interactive Silver Line map