A crew repaired one track at Silver Spring station while trains shared the other track during a fall weekend. (Robert Thomson/The Washington Post)

Q. Single-tracking
“On the Saturday and Sunday Martin Luther King Jr. Day weekend, the Orange Line was single-tracking between Courthouse and Foggy Bottom. Yet this was not announced in the weekend work list. Instead, you just listed the time between trains and said that trains would not be delayed once they reach your platform. This was not the case, as trains had to wait at Clarendon for the single-tracking area to clear. Why did you not announce the single-tracking to riders ahead of time?”

That Metro rider’s question was among many that we couldn’t get to during the hour when Metro General Manager Richard Sarles was my online guest Monday. But I want to take a crack at addressing the reader’s concern, since I think it’s shared by many weekend riders.

Here’s the short version: Metrorail doesn’t emphasize the location of the weekend work zone, the area where the trains share one track both ways, because it changed its strategy on weekend train timing last year.

Elaboration: Under the old system, the transit authority would put out an announcement each week specifying the weekend work zones where the trains would share tracks. The advisory would suggest riders add so-and-so many minutes if their trips took them through a work zone. Metro would append the advisory as a link from its online Trip Planner, but when you queried Trip Planner to get the timing and routing information for weekend travel, the results would not reflect the scheduled disruptions.

Like many other riders, I found this unsatisfactory. If the transit authority knew it was going to disrupt schedules two days out of seven for many years, it ought to find a way to take some of the guess work out of weekend travel.

Well, to Metro’s credit, things did change, but the results are imperfect.

Metrorail changed the weekend schedules to put more space between the trains. In theory, the trains should now be spaced out to the point that trains heading in opposite directions do not need to hold before taking their turn through the area where the track is shared. Meanwhile, Metro has found a way to adjust the Trip Planner information by midday each Friday so that it accurately reflects the schedule on each line for that weekend.

Earlier each week, Metro puts out an advisory about the weekend work. It still indicates the area where trains will share a track. Someone looking at the Orange Line section for the MLK weekend would have seen this.

Work Performed: Improvements to infrastructure, including rail joint elimination, rail and fastener renewal, leak mitigation between Foggy Bottom and Courthouse stations.”

In theory, the location of that single-tracking work zone shouldn’t matter. Whatever Orange Line platform a rider waited on between Vienna and New Carrollton, a train should have arrived every 20 minutes.

But for riders, there’s two practical problems with this system: One is that 20 minutes is a long time between trains. The adjustments made each Friday to Trip Planner are supposed to help riders minimize their waits on the platforms.

But that’s the second problem. It works only if the trains can keep to the schedule. Trains get thrown off schedule on weekends just as they do during the rest of the week. Fewer people are riding on weekends, so the platforms usually don’t get as crowded when trains are delayed. Still, a rider who needs to transfer to another line where the trains are widely separated may miss a connection and need to wait an extra long time on the weekend.

Weekend riders, what’s your experience? Do you still encounter delays after boarding trains? In general, do you prefer the new strategy on weekend scheduling to the old one?

Metro’s aggressive rebuilding campaign is scheduled to continue into 2017. During the online chat, Sarles answered one of my questions about whether he could have chosen another strategy for rebuilding, such as shutting down a line, or line segment, and getting work done in a shorter time. This is what he said:

Shutting down a line for an extended period of time has serious consequences for our customers and economic impacts on area businesses. I believe that such a shutdown should only be considered under extreme circumstances where there is no other way of accomplishing the work in a reasonable time. Each city is different; some have express tracks or other transit options nearby. By choosing to use shutdowns on weekends, many riders have other options available because the region’s transportation system is not congested during those periods. I recognize that there are those who are transit dependent and rely on Metro. That’s why we always provide alternate transit service.