An MTA LightRailLink vehicle by BeyondDC licensed under Creative Commons.

About two months ago, the Maryland Transit Administration (MTA) and its parent agency the Maryland Department of Transportation (MDOT) announced the rollout of real-time tracking and predicted arrival information for its Baltimore-based Light RailLink line. In so doing, they capped a five-year quest to bring riders the ability to know where all five of its fixed-route modes are and when they’re most likely to arrive at a given stop. And if that news doesn’t quite carry the same cachet as a new train station or tunnel or rail line, it’s still no less important in making Baltimore’s transit network reliable enough to live up to its potential as the area’s true economic engine.

One of the biggest difficulties in bringing real-time tracking to the entire MTA fleet was the unique set of challenges each mode posed, as well as how each mode interacts with the GTFS (General Transit Feed Specification), an industry-standard set of programming developed in 2006, which allows agencies to put their stops, trips, routes, and schedules all in one formatted file usable by apps like Google Maps and Transit app.

“Each one of these modes is kind of a different animal and requires kind of a custom approach on each one of them”, said Michael Helta, the MTA’s Chief Innovation Officer and one of the primary figures involved in the tracking rollout.

Transit tracker screenshot of MTA Local Bus routes by the author.

Take Local Buses, where aging fleets and equipment posed many of the initial problems. “Buses, at the time, back in 2017, we were between technologies,” Helta said. “We had equipment on the buses that was not providing very frequent information as to where our vehicles were and honestly, at any given time, we weren’t seeing 25-30% of our buses.”

What the MTA wound up doing was putting GPS trackers on each of its buses, including frequency, and setting them up so that they’d update every ten seconds. From there, they used the active dispatcher systems they already had to incorporate information on which routes the buses were actually on, and officially launched real-time tracking for local buses in June 2018.

The unique characteristics of the Commuter Bus and MARC tracking systems

Transit tracker screenshot of MTA Commuter Bus by the author.

The next two modes to get real-time tracking, Commuter Buses in June 2019 and MARC (Maryland Area Rail Commuter) in August 2020, were a little trickier. Part of that was because the MTA’s Local Buses themselves belong solely to the MTA and their drivers are MTA employees while Commuter Bus service is outsourced to various contractors, each with their own fleets. Likewise, the tracks for MARC’s 3 lines are owned by Amtrak and CSX, with the MTA also contracting their operations out.

But there was an even more important complication, especially for MARC: “We were lucky in that both of those modes were already working on this and trying to provide this information to the customers,” said Helta. “The issue that we found there was that the arrival information on the vehicles wasn’t in the GTFS. You could tell where some of the vehicles were because there was a MARC Tracker but there wasn’t any reference to the GTFS, which is kind of how that format works.”

Transit tracker screenshot of MARC by the author.

That meant Helta and his colleagues had to essentially reformulate how that arrival information was provided and then package it and put it into the GTFS Realtime Feed so third-party providers like Transit app and Apple could convey it accurately, then work with contractors to duplicate that effort for Commuter Bus service, including making sure they had the necessary equipment on their vehicles.

Bringing in Metro SubwayLink and LightRailLink

That left what proved for various technical reasons to be the two hardest modes of all, Baltimore’s Metro SubwayLink and LightRailLink. The obvious challenge in setting up real-time tracking and arrival for Baltimore’s Metro Subway was that over ⅓ of the 15.4-mile heavy rail line and eight of its 14 stations are underground so the MTA’s past approaches for GPS wouldn’t work here. There was, however, a legacy system already in place for Metro which allowed the MTA’s control room to know which track circuit a train is in.

“We know where they are on the track circuit but those track circuits were on a schematic that had no reference to an actual latitude or longitude,” Helta said. “So how do you map where a train is if you don’t have any reference to a map?”

The answer, it turns out, is that you map out each of the circuits, working with MTA engineers to identify where each of those lie and how long each one of them is and allowing them to enter the information from the legacy system into the GTFS. It was a painstaking process but it finally paid off with the official launch of real-time tracking for the Metro Subway in December 2021, the first time that system’s ever had any real-time information since its 1983 opening.

Transit tracker screenshot of MTA LightRailLink by the author.

The Light Rail, on the other hand, while holding the advantage of being entirely above ground, in many ways offered even more technical challenges than Metro. That’s because the MTA is actually in the middle of an extremely extended overhaul of its entire Light Rail fleet.

“So half of the trains have new hardware and half the trains have old hardware and they both report in different ways,” said Helta. “And so we basically had to work to keep the old hardware continuing to provide information and then aggregating that with the new information coming off of the overhauled vehicles. So that took a while to make sure those processes worked together so we could get a consistent idea of where all the trains were.”

On top of that problem, Helta said, the MTA hadn’t been assigning its vehicles to trips in a way that was “agreeable” to the GTFS, which meant its engineers and programmers had to work with its Light Rail dispatch team to come up with a system to figure out which train was on which trip.

“That in and of itself isn’t incredibly challenging,” Helta said. “The big thing with Light Rail is we also have signs at the stations that give you dynamic information. That was coming from another legacy system and at times, it provided different information than what our GTFS RT (feed) was providing. One of our goals is making sure that when you look at anything we give you information on, it’s going to give you the same exact thing. And in this instance, it wasn’t, it was pulling from a completely different system that wasn’t as accurate.” Eventually, Helta and the MTA were able to take the new GTFS feed and parsing it through some old programming protocol language to feed it into the legacy sign system. And with that, Baltimore Light Rail’s first true real-time arrival information system launched the week before Labor Day 2022.

What happens next

Neither Helta, his colleagues, nor most MTA riders would call the agency’s real-time tracking perfect just yet. While the MTA is in the process of upgrading its cellular service along the Metro Subway, it’s still quite easy to lose reception along the underground portions of the line and the tracking remains fairly vulnerable to sudden interruptions like bus diversions, single-trackings, speed restrictions, schedule changes, and closures like the one scheduled to shut down Light Rail service in most of Downtown Baltimore for four months next spring.

But, as Helta noted, these are all problems every transit agency has to deal with: “Our first goal was to get the real-time feed up and running. The next step is to take it to the next level, where we are communicating diversions in a much more accurate and proactive way.”

And for a transit agency that’s seen its services delayed and impeded at times over the past five years by everything from sinkholes to freight train and Amtrak traffic, giving its riders the ability to have a reasonable idea of where their ride is and when it will reach their stop is just as potentially transformative as any new physical infrastructure it might build in the next five years.