At our recent forum about the Green Line’s future, MBTA General Manager Frank DePoala offered hope for continuous improvement of reliability, with modest resulting capacity increases, but no hope for big capacity increases within the visible planning horizon.
The General Manager’s frankness and his hands-on familiarity with many specifics of the Green Line’s operations and needs were very reassuring. And he reported good progress on many of the short and medium term goals identified in previous meetings. But the dose of reality he offered about the long term will require some time to digest.
The potential demand for service on the Green Line at rush hour substantially exceeds existing capacity — full cars go past full platforms and many people have given up and chosen other modes of transportation.
I had picked up on suggestions made by the previous management team that if we could move from two car trains to three car trains during rush hour service, the throughput could be greatly increased.
I was thrilled in 2013 when the Patrick administration included hundreds of millions for the new vehicles and power upgrades that three car trains would require in its transportation vision. I made it my mission to advocate for the funding to support that plan.
My first letdown came as it emerged over the following year that actually, there was no medium term prospect of acquiring a new Green Line fleet — many of the existing vehicles had just been refurbished and federal standards might even prohibit the use of federal funds to replace them.
Further, it emerged that even if the fleet could be expanded, there was no place to house additional vehicles — layup and maintenance space for Green Line vehicles are already inadequate.
Last night, the GM identified an additional constraint that puts three-car trains beyond the planning horizon: Currently the underground stations of the Green Line are long enough to allow two two-car trains to discharge passengers simultaneously. Three-car trains are just too long to allow this and the result of adding them would be greater congestion in the core tunnels. Expansion of the underground stations is not a feasible idea to discuss.
The GM also offered some insight into the decision not to immediately go forward with diesel motorized units — an alternative approach to serving some of the same neighborhoods served by the Green Line. DMUs are independently powered subway-like vehicles that could run on existing rail lines. The problem is that they really can’t coexist with commuter rail service at rush hour, so they wouldn’t add capacity at the times of day when additional capacity is actually needed.
The more realistic hopes are for modest capacity increases through a host of fixes and upgrades that will improve reliability and reduce delays. These include upgrades to the signal and power systems, some components of which are over a century old, and synchronization with traffic signals on the above ground segments. These projects are clearly appropriate and actually underway.
One of the other recent improvements is the installation of GPS tracking for all the Green Line cars. This allows better passenger information and also better performance information. Given the incremental nature of the change we can expect in the Green Line, we should focus on understanding the new performance metrics and using them to see if improvement is actually happening.
We should, in addition, make sure that the vehicle replacement procurement does get teed up so that it is ready when the current fleet reaches obsolescence in the middle of the next decade.
As always, I greatly appreciate your input on these issues.
A further comment about three-car trains (5/5/2016)
Routine use of three-car sets is 10 to 15 years away. The issues previously raised as barriers to the use of 3 car train sets — power limits, the current lack of vehicles, the current lack of maintenance space, the incompatibility of the model 7 and model 8 cars in 3 car sets ( combined with the need to mix them to provide accessibility ) — suffice to convince me of that. However, these have all seemed to be issues that could surmounted over a 10 to 15 year time frame.
An additional issue was raised in the presentation — the possible incompatibility of three car vehicles with efficient flow in the core tunnels. I’ve gotten conflicting reads on the issue in various sidebar conversations.
So, I haven’t quite been able to accept that we should abandon three-car sets from a 15 to 25 year perspective. The lead times for new maintenance facilities are long enough that, if three-car sets are viable in the very long term, they perhaps should continue to be part of our conversation now. I will not let this issue go until we get more clarity on the core tunnel issue.