Saturday, February 2, 2013

Thinking about station elimination along the Green Line





Original Article:


A common complaint among regular "B" branch riders is the excessive number of stations on the line: particularly in the Boston University corridor between Kenmore and Brighton Avenue stations. Four pairs of stations are less than 250 meters apart, each, as can be seen on the above diagram. The train typically takes 12-15 minutes to cover the 2.5 km on that stretch, which comes out to an average speed between 6 and 8 mph. The 57 bus shares this portion of the route and usually averages to a slightly higher speed than the train.

The topic was mentioned a few times at the recent public meeting and a member of the service planning department indicated that some internal study had been done but nothing had come of it. The main concerns had focused around balancing the increased walking distance for some patrons vs the improved speed of service for others. These are valid points to consider but I believe they may be putting an inappropriate amount of importance on reducing walking distance.

So what is the right inter-station spacing? One quick rule of thumb might suggest 400 meters (a quarter-mile) for local-stop service. But it's also more complicated than that. For one thing, there may be obstacles which prevent an ideal spacing, particularly for the Green Line which crosses many streets. And there is room to bend the rule for certain spots, depending upon the local context. And we still have to decide what the Green Line really should be: should it be a local bus? Or something nearer to rapid transit quality?

I don't expect agreement on all these points. But I don't think there is anyone who disagrees that 250 meters is too short, and that 6-8 mph is too slow. The questions are: which stations should be eliminated and/or consolidated? Should we split the platforms so that they are always on the far-side of traffic lights, in anticipation of signal priority? If we do consolidate stations, will the new one be able to handle the passenger load?

I'll start with one possible idea, and see if anyone else wants to suggest something.

Alternate 1:

Keep Blandford St; eliminate BU East; split BU Central; keep BU West; eliminate St Paul St; split Pleasant St; eliminate Babcock St; keep Brighton Ave.

This one is pretty heavy on the eliminations, approximately doubling the inter-station spacing. Although the BU platforms receive heavy usage, I believe that usage is more uniformly distributed throughout the day rather than at evening peaks. Also the reservation is wide enough at that point for bigger stations, although the current stations are narrow due to excessive landscaping.

Several of the stations are split into far-side platforms. But this technique cannot currently be applied to Brighton Ave or Blandford St because of switches that are in the way.

4 comments:

  1. I don't believe station consolidation is a reasonable answer in this situation; signal priority and relocating platforms to the far side of the intersection can increase throughput much more effectively without reducing transit coverage.

    While we're relocating platforms, let's get pavement in the right of way so that the 57/A can benefit from the improved platform positioning, signal priority, and, most significantly, the dedicated right of way. The 57/A can share the ROW with the B between Packard's Corner up until just before Kenmore where it can rejoin traffic in the correct lane before entering the square. This will increase vehicle frequency and subsequently station dwell times from decreased queue volume that needs to be managed by each vehicle.

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    1. Well, I believe signal priority will also be important and I will cover that in another post. But I think that having stations only 250 meters apart is a bit ridiculous, and it's an issue that pretty much everyone I talk to will bring up and easily understands. I think there is a strong case to be made for at least one station to be eliminated on each side of the BU Bridge, in addition to signal priority and other reforms.

      As for paving the right-of-way, I've thought about that in the past. It would also be good for emergency vehicles if done right. But, assuming all the little details of getting the bus in and out of the lane could be worked out... I think there's a danger. By putting in pavement you are effectively sending a message to motorists: "hey, there's another lane available here." I'd rather not go down that road.

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  2. I guess Alternative 2 would be to eliminate Blandford St, move BU East eastward at least to the other side of the street (which may require changing the track layout), and merge St. Paul and Pleasant St into a single new stop. Blandford Street is rather close to Kenmore, and the latter should have a larger sphere of influence as it has much better frequency and connectivity.

    I think there's definitely something to be said for stop consolidation here if it will speed up service, but also various other operational improvements including signal priority, POP or off-board fare collection, and capital improvements like wider platforms. Ultimately, I think some of the problem is that this section of the line doubles as BU's campus shuttle, which puts a very high load of very short trips on this particular section of the system. I almost wonder if short-turning trains at Harvard Avenue or so would make sense to provide more frequent service on the inner part of the line, and less frequent but hopefully more reliable service on the outer part.

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    1. I'm not sure of the feasibility of relocating the storage track at Blandford Street, or how much that might add to the cost. Not a bad idea if feasible though. I'll note it down.

      I think that students aren't using it so much as an intramural shuttle as an Allston/campus shuttle. The BU shuttle is free and more convenient to their facilities. Big crowds typically let out at Packard's Corner and Harvard Ave. When they rebuild that section of Comm Ave they ought to consider a storage/turnback track after Harvard Ave, but that's out of scope for this post.

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