Green Line Update Teases Improvements Enabled by Tracking Technology

As a corollary to our guest contributor post on the disappointing improvements and issues with Commonwealth Avenue, we have a few (much delayed) updates about the T's more progressive plans to improve transit along the corridor.

Back in June, I had the pleasure of attending a forum on Green Line issues hosted by the MBTA and facilitated greatly by Senator Brownsberger. The presentation included updates on the primary issues afflicting the Green Line and its dependent riders as outlined by Brian Kane, MBTA Director of Policy, Performance Management & Process Re-Engineering and former budget analyst with the MBTA Advisory Board.

Others present at the meeting included leading MBTA staff that Dr. Scott heralded as subject matter experts to ensure questions could be answered directly by the most appropriate person from the agency. Top MBTA management included:

  • Dominick Tribone for questions on information systems
  • Bill McClellan, Director of Green Line Operations
  • Laura Brelsford, Deputy Director of System-Wide Accessibility
  • Melissa Dullea, Director of Planning & Schedules

Mr. Kane broke down the issues into 5 key areas and highlighted the improvements the T is aiming to tackle over the long run.


The biggest hindrances to speed right now are the incredible closeness of stops on some lines, the lack of signal preemption, and restrictions from fare collection and public outcry about boarding policies.

At the moment, the C line is the slowest, averaging 11.1km/h (6.9mi/h) with an average stop spacing of about 305m (1000 ft), while the D is the fastest, averaging 30.6km/h (19.5mi/h) with an average stop spacing of about 1.2km (4,000 ft).

Stop Consolidation

The number of stops increases time the train spends either stopped or slower than cruising speed. Even if the volume of passengers stays the same, the math still works out to be that the train spends more time slowing down to stop at each stop. Further, each stop that a train has to make before a stop light increases the chances that the train will miss a number of green cycles and get stuck at a red light. Of course, the real culprit of slow loading times is a capacity issue, which we'll discuss below. Ultimately, the promise is faster train speeds at the compromise of increasing the walking distance for some.

The MBTA is considering consolidation of several stops along Commonwealth Ave to improve speeds on the B Line based on low average boardings and absurdly close stop spacing.

Brian Kane commented that the MBTA has championed stop consolidation before, but the issue is as polarising as the issue of fare collection. A survey in 2005 showed widespread support for stop consolidation while seemingly as many people come out to defend the need for a stop as the people who clamor to remove it. At the moment, there are no plans to make further consolidations, but monies have been issued for a Commonwealth Ave improvement scheme. Dr. Scott underscored the fact that part of the money earmarked for the project is in danger of expiring, so it needs to happen soon. The MBTA is in talks with BU about potential streamlining along the corridor.

Fare Collection

This has been one of the hottest button issues that has plagued the T, transit advocates, and the public at large. We could fill a whole post about fare collection issues alone. The long and short of it is that everyone wants two things:

  • collection of fares from everyone
  • all doors boarding

The solution is something everyone else seems to have solved outside of Boston: proof of payment (POP). The cool kid on the block right now is San Francisco's MUNI, who implemented the first system-wide POP deployment in the 2012 - yes, all trolley lines and buses permit all-doors boarding.

POP was brought up multiple times in the meeting with respect to addressing the public's outcry to close the budget hole of fare evasion before turning to the public for more funding. The MBTA's response was to force front door boarding on all Green Line trains outside of rush hour and the issue was polarising.

As Mr. Kane underscored, the MBTA did exactly what people complained about in budget hearings. The front door policy makes it harder for the people to evade fares. However, those people are costing the T at most less than 1% the total $400 million in fares collected annually, much less the total $2 billion annual budget. We've talked about fare evasion here before.

Dr. Scott added that at some point the cost of countermeasures to minimise the loss from fare evasion starts to cost more than the nearly immeasurable actual losses from fare evasion. To punctuate that, I added that some transit agencies elsewhere account for losses from fare evasion as the cost of business.

Fare validators like this one at the rear of a San Francisco MUNI bus would need to be installed to truly facilitate proper fare collection at all doors on the Green Line.

At the moment, the T neither has the funding to increase the number of fare inspectors nor the funding to add fare collection equipment at all doors on the Green Line, as was done in San Francisco. In the long run, the vision is to replace the fare collection system completely, ideally in favour of a contactless payment system already embedded into many debit and credit cards today. The T will eventually join the increasing number of systems, including TfL in London and CTA in Chicago, that are making the move away from standalone fare collection systems that require them to effectively act as banks to manage rider transactions. This has been one of Dr. Scott's biggest long-term goals from day one and has come up in MBTA ROC meetings a number of times.

The ticket vending machines at Resevoir on the D Line next to the validation machines.

Currently, some Green Line stations do have fare validation machines, but to most passengers, it's not clear what they do. 

Dr. Scott also offered to continue the conversation about fare collection and boarding policies through a broader charette to envision an end goal and actionable steps to achieve that vision (ideally of system-wide POP for the T).

Signal Preemption/Traffic Signal Priority

One of the major projects for the T is the upcoming tracking system, which will be launching in December of this year and cost a mere $13.5 million. This is a fraction of the cost of a full-blown train protection and control system that was last estimated to cost over $770 million at full build-out.

However, the current upgrade promises location awareness of Green Line vehicles sooner rather than later. Once we have a live, automated system that tells us where Green Line trains are, the MBTA can then start better spacing and management of trains, passengers will finally know roughly when their trains are coming, and most importantly we'll be able to tell the lights to change when a train is approaching. This is the miracle of traffic signal priority or traffic signal preemption.

The MBTA is working very closely with BTD and the city of Brookline's transport department to examine the impact of and ensure the success of traffic signal preemption once the automated vehicle location (AVL) system is switched on. The AVL will be able to communicate with Boston's centralised traffic management computers the location of trains. As trains approach an intersection with a green light, it can request that the light be held green for a little longer to let the train through. As trains approach an intersection with a red light, it can request that the red be shortened to let the train go through sooner.


Frequency is a function of speed and volume of vehicles available. If vehicles can travel faster and there are more of them, naturally trains will pass any given point on the line more frequently.

At the moment, frequency is largely bound by the number of trains in the fleet. There are currently 215 individual Green Line cars at the moment. 86 of the oldest trains, are going out for overhauls to improve reliability and ensure they can continue running through the first quarter of the 21st Century. The first of the overhauled trains will arrive this autumn and they will continue to arrive through the autumn of 2016. The biggest passenger-facing changes in the overhaul will include:

  • conversion of all lighting to LED
  • new seats and interiors
  • ADA-compliant door warnings and signals
  • improved heating, ventilation, and air conditioning (HVAC) systems

Green Line Type 9 concept rendering by Spanish manufacturer CAF.

As recently announced, the MBTA will also be getting new trains, designated Type 9, for additional capacity. They will also help maintain the current level of frequency in spite of the additional distance trains will have to cover for the Green Line extension through Somerville as it comes online between 2017 and 2019. Ultimately, all Green Line cars except for the Type 9 cars are provisioned to be replaced as part of the Governor's Way Forward plan.


If frequency is dependent on speed and fleet size, capacity is dependent on frequency and fleet size. It is a measurement of the overall volume of people who can be moved at peak travel times.

As mentioned, the Type 9s will be adding capacity to the system. Additionally, 8 cars that have been out of service in the long term are part of the 86 older cars that are being refurbished; this will add just a bit more capacity to the overall number of trains available for service.

However, the fleet capacity itself is limited until we have someplace to put the new trains. A new yard needs to be constructed to store and maintain the trains the T is buying. This is why the Type 9 trains won't be arriving until the Green Line extension's first phase is completed in 2017 since that part of the extension will include a new yard for Green Line trains in Somerville.

3-Car Trains

The Green Line's capacity is also limited by the power system. The current power systems that pump electricity through the Green Line's trolley wires aren't powerful enough to run 3-car trains close together. Since 3-car trains can't be run close together, you end up with the same effective capacity of three normal-sized 2-car trains at their regular frequency.

The MBTA is currently planning a study on the power systems of the Green Line in conjunction with the Red and Orange lines to figure out exactly what equipment needs to be replaced or added.


As a bonus from the installation of the $13.5 million tracking system, riders will be able to see when their trains are actually coming, satisfying the long-time feature request of Bostonians since the late 20th Century.

Again, the Green Line tracking system will go live in December of 2014. In 2015, the T will go live with train time predictions 


Station upgrades are being completed as the original round of ADA projects comes to completion. These have included a number of projects and are culminating in the 2-year renovation of Government Center station.

The T is already ramping up plans for a second round of projects to further improve accessibility of stations, including a number of Green Line stations. Financing has yet to be dedicated to this second set of accessibility projects, but will likely follow the release of cost estimates as the T closes in on the scope of the projects they want and need to include.

This second set of projects is also a perfect opportunity to adjust station placement for better service. In particular, stations that are currently placed on the near-side of intersections can be moved to the opposite side of the intersection. This would complement signal preemption since trains would be able to cross the intersection to a stop on the far-side instead of having to stop before the light to pick up passengers regardless of whether the light is green or not.