The MBTA commuter rail lines are laid in such a way that there’s an inherent tension between providing local service and providing longer-distance intercity service. It’s less apparent on the Providence Line because the intercity component, i.e. Boston-Providence, follows immediately just from serving the suburbs between Boston and Providence, but elsewhere there are greater problems. Good local service would have intense frequency in the inner portions of commuter lines; unfortunately, most lines only meet right next to the termini, reducing the opportunities to use interlining to create high-frequency inner segments.

Good local service also needs many infill stops, while good intercity service needs higher speeds. My proposals for the Providence Line essentially go with intercity service needs, justified by the facts that Providence is a major anchor, that high top speeds are possible on the line, and that the line should also host high-speed trains. Fortunately, the Providence Line has an opportunity for more intense local service using the Stoughton Line to add frequency; while this would end up overserving Canton Junction and Route 128, Readville and points north would get adequate peak service, and acceptable off-peak service. This is not as true on other lines, especially on the North Side, in which there’s a tradeoff between fast service to outlying cities and good service within Cambridge and Somerville.

Of course, the issues I’ve focused on in my previous post on the subject – electrification, high platforms, modern rolling stock – are useful for both. A fast-accelerating EMU could connect Boston with the various terminals at the same time as today’s express trains while making all stops as well as some extra infill stops. The problem comes from trying to fit trains into a clockface schedule. On a few lines, for example the Lowell Line, it’s actually easier to close very lightly used stations (Mishawum) or stations that are very close to other stations (Wedgemere).

Another issue is outbound extensions. With some, there’s so little traffic beyond the current terminus, or sometimes even beyond a point slightly closer than the current terminus, that the decision should be easy. This contrasts with the MBTA’s approach of proposing more and more outer extensions. With others, the intercity functions make extensions more reasonable, within certain bounds. I believe the following list of judgment calls would be reasonable:

1. Providence Line: no extension required – the line’s natural end is Providence. If Rhode Island wants to provide a low-frequency glorified parking shuttle from Wickford Junction and the airport to Providence, it’s its business, as long as it doesn’t muck up timetabling that’s based on Providence-Boston service.

2. Stoughton Line: an extension to Taunton would work, and possibly even to New Bedford. I’m iffier on Fall River, which has stronger commute ties to Providence; however, Providence-Fall River requires too much new infrastructure to be easy.

3. Franklin Line: either extend it to Milford (which may be easier to serve from the Worcester Line), or cut it back to Franklin. The Forge Park terminus is close to a lot of office park jobs, but the local road network is so sprawled out that it’s not worth the extra few minutes of travel time.

4. Fairmount Line: building infill stations is an excellent idea, though it should be coupled with increase in frequency and service level to make them more useful. One way to improve off-peak frequency is to route all Franklin Line trains along this line, and perhaps add supplementary trains that turn at Readville. The advantage of this is that the Fraknlin and Fairmount Lines used to be one railroad, with a grade-separated crossing over the Providence Line; in contrast, the junction at Readville is flat, making it more operationally cumbersome to have trains cross from one line to the other.

5. Needham Line: no extension necessary – the only possibilities would dismember the line in favor of much lower-density suburbs than Needham. Better would be to eliminate the line entirely and put Needham on a branch of the Green Line, and restore past plans to extend the Orange Line to West Roxbury. This would dismember the line too, but in favor of more service to dense areas rather than less. I don’t know what’s Needham’s commute tie to West Roxbury, but its commute tie to Newton and Brookline is fairly strong, 1,300 vs. 3,400 to Boston and another 3,400 in-town.

6. Worcester Line: Worcester is the natural terminus, so no extension should be entertained.

7. Greenbush Line: Greenbush is the natural terminus. The greatest urbanization is on the coast rather than along the railroad, and this limits the line’s usefulness.

8. Kingston/Plymouth Line: the natural terminus is downtown Plymouth, slightly farther out from the current Plymouth station, which should be renamed North Plymouth or just closed for lack of utility. In addition, Plymouth sends Boston 2,565 commuters, and Kingston only 797. Either the roles of Kingston and Plymouth should be switched – Plymouth would get served all day and Kingston would get only supplemental rush hour trains – or the Kingston branch should be closed, and replaced with a station on the main line.

9. Middleborough Line: for ordinary regional traffic, the line should be marginally cut back, to place the Middleborough station at the center of the town. In fact, there’s a dropoff in commute volume south of Brockton, and yet another south of Bridgewater; Middleborough is a fine terminus, but is not a proper anchor like Providence, Worcester, or especially Plymouth. On the other hand, there’s some potential for intercity traffic to Cape Cod, capturing some commuters as well as vacationers heading the other way.

10. Fitchburg Line: the MBTA’s proposed extension to Gardner looks weak to me, though not completely daft. That entire region of northern Worcester County has much stronger commute tie to Worcester than to Boston, in similar vein to the issue of Fall River’s connection to Providence. The commute tie to Framingham, as in the MBTA plan to have a branch leaving Framingham toward Leominster, is even weaker than that to Boston. It would be better to have a regional line connecting Gardner to Worcester, which would also have the advantage of taking a much more direct route than the freeway network; connecting Fitchburg and Leominster would require more work and compete with I-190 directly.

11. Lowell Line: here an outbound extension is natural and desirable, since Nashua and Manchester have a nontrivial commute tie to Boston and are significant cities in themselves, though as with Cape Cod this would be more of an intercity line. New Hampshire had a plan for such an extension, but it was killed by state Republicans early last year. This is unfortunate, since Nashua in particular has a less than great freeway connection to Boston, which a fast electric train could consistently beat.

12. Haverhill Line: Haverhill is a natural terminus. Although Rockingham County has a strong commute tie to Boston, the greatest part of it comes from very sprawled out towns near I-93, far from the line.

13. Newburyport/Rockport Line: the split at Salem allows natural interlining to give the towns with the strongest commute ties the most frequency. An additional branch to Marblehead would be prudent, providing even more frequency to Lynn, Chelsea, and additional infill stops in Revere. At the north end, Portsmouth looks like a fine intercity terminus, but in fact that part of Rockingham County is a marginal commute market to Boston, better than that feeding into Haverhill but much worse than the I-93 sprawl.

Not discussed above are station placement and infill stations. Station placement is relatively easy, since bad cases like Westborough and the aforementioned Middleborough and Kingston look obvious on a map. In addition, such office park stations with terrible ridership as Mishawum and River Works are already treated as such, so almost all trains skip them and their ridership is very low, making them clear candidates for closure.

Infill stations are harder. The problem is that on the North Side, the four lines split too early. This means that, while infill stations are possible, it’s hard to give them adequate frequency. Short-turning local trains could help somewhat, but is the most difficult on the two lines that serve Cambridge and Somerville, the Lowell and Fitchburg Lines. It’d be much easier to do this with Lynn (which already benefits from interlining and would benefit even more from a Marblehead branch) or Malden (which has the Orange Line).

That said, the Lowell Line might be able to support a local train to Winchester and an intercity train that makes zero or one intermediate stop between North Station and Winchester. The commute market is not great at this distance, though; Belmont has 3,100 Boston-bound commuters, and 290 inbound riders at its two commuter rail stations. A reroute of the Fitchburg Line along the Charles River Branch through Watertown might get more ridership; it would be slower, but it has zero intercity function, compared with strong potential at and east of Brandeis. To succeed, high frequency and short station spacing are required. For an example using the Charles River Branch, see here.

On the South Side, the Worcester Line begs for infill between Yawkey and Newtonville, but some of the people it would serve may already be riding the Green Line. The Green Line doesn’t perfectly parallel the line the way the Red Line parallels the Old Colony Line or the Orange Line parallels the Providence Line and the Haverhill Line, though, and there’s room for two or three stations serving Allston, Brighton, and Nonantum. On the other hand, some of these stations would compete with Watertown somewhat, and are less ideally placed in that the Worcester Line has an intercity function whereas the Fitchburg Line doesn’t.

Finally, another unmentioned issue is the effect of rapid transit extensions, especially of the Green Line. The extension plan to Somerville, which the state is obliged to build as one of many mitigations for the traffic induced by the Big Dig, is effectively a replacement for Lowell Line infill in Cambridge and Somerville; the line would only really need one infill stop to connect to the Green Line, and perhaps the Green Line would need to be extended to West Medford, if not to Winchester. That said, the interaction with rapid transit is more complex than this, and I will discuss it more in a future post.

The MBTA has a problem. And I say this coming from New York, whose standards for good regional transit aren’t all that high, but now Metro-North looks like something to look up to from the MBTA. Ridership on the system is rising, but not very quickly; the MBTA moreover has no plans to modernize. Most of what I’m going to suggest will involve commuter rail, not because it’s the most important portion of Boston’s public transportation but because it’s the part I’m most familiar with and also the part that seems most direly in need of improvements. Put another way, I’m necessarily going to talk about the MBTA as perceived from Providence, rather than from within Boston.

The main difference with New York and past proposals for improvements, both subway extensions and regional rail, is size, and scope. In New York, practically everyone who works in Manhattan takes public transportation or walks. The transit mode share to Boston is lower and the car mode share is much higher. This seems especially true for people commuting from north of Boston.

The main prescriptions will not surprise people who have read my posts on best industry practices. In short, the MBTA commuter rail needs to do the following:

– Full electrification, starting from running EMUs rather than diesels under the catenary on the Providence Line, but also extending to all other lines.

– Level boarding along the entirety of all platforms, rather than just one car length, in order to shorten dwell times to no more than 30 seconds at outlying stations.

– Higher-quality rolling stock, with better-configured doors than the present cars as discussed in a DMU conversion study; all new EMUs available, both FRA-compliant and noncompliant, would be fine, though noncompliant trains with a waiver would have somewhat better performance and lower operating costs.

– Reasonable frequency all-day on a simple clockface schedule: ideally, all branches should have 4 trains per hour at the peak and 2 off-peak – the lowest-ridership lines tend to be the shortest-distance, for which frequency matters the most, whereas the highest-ridership lines (Providence, Worcester) are practically intercity, the higher demand balancing out a lesser need for frequency.

– A fare union with local buses and the subway, so that commuter train tickets are automatically valid without extra pay.

– Relocation of stations to walkable urban areas, away from park-and-rides that only serve to extend the suburbs into Boston rather than extending Boston into the suburbs.

– An end to outbound extensions, such as the ongoing project to extend the Providence Line to Wickford Junction, and instead a shift toward infill stations, especially in underserved Cambridge and Somerville.

In the longer term, a North-South Rail Link is unavoidable – North Station is too far from the CBD, some through-service from south of Boston toward Cambridge is advisable, and the rail link as proposed would give a direct connection to the Blue Line and thus to East Boston and the airport. Although the official cost estimate is $9 billion, for barely 2 kilometers of tunnel and associated connections, such an estimate would make the project more expensive km-per-km than any other I know of except perhaps East Side Access, and a more honest attempt at cost estimation yielded $3-4 billion, on a par with outsized American subway construction costs; at European costs, it would be less than a billion. Observe that electrification could reduce the cost by allowing steeper grades; the official proposal still uses heavy diesel locomotives. In either case, this is far more expensive than the points above; concrete costs much more than organization and electronics.

Let me now explain in more detail what’s happening in and around Boston – more precisely, what is wrong, and potentially what ridership level should be expected of good regional rail.

The main datasets I’ll be working with are the American Community Survey as of 2009, the town-to-town commuter flows as of the 2000 census, and the MBTA Blue Book, offering ridership numbers as of 2009 and going back to 1989. Bear in mind that most data from the 2009 ACS will be scrubbed from the net on January 20th, giving us only 2010 census-based numbers, which undercount immigrants and the poor and thus undercount cities; however, while the 2010 census gets magnitudes of change wrong, it’s very close in terms of absolute populations, absolute mode shares, etc. All numbers I cite here are from the 2009 ACS; you can verify that a source exists now, but not beginning a week from now.

The current background trends to observe are:

– Boston’s population is increasing, quickly. The 2000 estimate base, using a 2010 backdate that also depresses intercensal estimates to fit the 2010 undercount, was 692,745 for Suffolk County, which contains Boston and three small inner suburbs. By 2009, the county’s population was 753,580, a growth of 8.8%. Boston itself had 9.5% growth from the 2000 census, which is not directly comparable to the ACS and the estimate base but is extremely close in numbers. The metro area grew only about 4.5% over 2000 – a little less if one takes the full Combined Statistical Area, which includes slow-growing satellite metros like Providence.

– Transit ridership has grown in the last 10 and 20 years, but by much less than in New York. The Red Line’s grown 50% in the last 20 years, but the other T lines barely grew. The commuter rail grew quickly as lines were put into service in the 1990s, but had little growth in the 2000s, despite high gas prices.

– The Silver Line BRT is very underused, despite the promise and branding as rapid transit on tires. Even for airport service, where the Silver Line gets to the terminals, it gets less than half the ridership of the Blue Line (2,600 vs. 6,900), which only serves a station connected to the terminals by free shuttle buses. The Washington Street branches (SL4, SL5) are more frequented, but their combined ridership is only about the same as that of a single subway station, and are just bus-plus.

– Boston is the opposite of a bedroom community – it has 520,000 jobs vs. 278,000 employed residents, all as of 2000. This 1.87 ratio is much higher than that of New York (1.18), which contains most of its bedroom communities, and is more comparable to that of Manhattan (2.75). The same is true of Cambridge, with 114,000 jobs and 55,000 employed residents, for a ratio of 2.08.

– Unlike New York, both Boston and Cambridge draw substantial numbers of commuters from suburbs outside urban transit range – Boston draws about 200,000, and Cambridge draws about 55,000. Inbound commuter rail ridership on the MBTA is 70,000. Cambridge is a lost cause under current operating paradigms – it has no stations, and if it did they’d be too poorly integrated with the top two employers.

– Total transit vs. car mode share is 26-52 for people working in Cambridge and 37-50 for people working in Boston; the corresponding numbers are 56-29 in New York (including bedroom communities like Queens) and 73-14 in Manhattan (which is more comparable to Boston in terms of workplace geography).

– There are about equally many suburban commuters into Boston from the north as from the south. People driving to the edges of the Orange and Red Lines cannot make too big a difference (Alewife has 2,700 parking spots, and Malden and Oak Grove have just under 1,000 between them), so the difference seems to be that more people are commuting into South Station than into North Station. Observe that South Station is right next to the Boston CBD, whereas North Station is a little farther out.

– Boston has built too much highway infrastructure for a kernel of a transit-oriented edge city to exist along Route 128 as it does in Stamford. 10% of people who work in Stamford take transit to work. There aren’t numbers for all edge cities near Boston, but where they exist, they’re much lower, e.g. 2% in Burlington. Furthermore, since Route 128 exists and is continually upgraded, there’s not much hope of serving these centers by commuter rail from suburbs on the opposite side of Boston.

The upshot of all this is that there’s room to more than triple MBTA commuter rail ridership, while also maintaining healthy urban rail ridership coming from population growth in Boston itself. However, this requires very good service from the suburbs to the city, and the MBTA isn’t providing it. The problem is that the MBTA relies too much on cars: Middleborough and SouthWestborough are particularly egregious for their poorly located stations, chosen for drivers’ convenience rather than for that of transit users. Even worse, Plymouth, a city that’s older than Boston, gets few trains, while most trains serving the Plymouth Line instead stop at a park-and-ride nearby, at Route 3.

Although the focus of all suburban rail is service to the urban core, this can only be done by treating it as longer-range, lower-frequency rapid transit, rather than by treating it as shuttles from parking lots to the CBD (or almost the CBD, in North Station’s case). People won’t use the trains if they’re too infrequent past rush hour; it’s not 1960 anymore, and people do not always work 9-to-5.

For an example of what the MBTA is doing wrong, let’s look at commuter flows in Rhode Island. There are 4,700 people living in Rhode Island working in Boston. The biggest single source of Boston-bound commuters is Providence, with 1,100; Providence Station has 2,000 inbound weekday riders, so it also draws people from some nearby suburbs – but not too many people. Cranston and Warwick have 700 between them – and they’re getting an airport stop with a very small number of trains. Even Washington County, with 170 commuters, is getting a station. Those two stations cost $336 million between them. Meanwhile, Pawtucket, with 600 commuters plus another 800 in suburbs to its northwest and in Woonsocket, is not getting an infill station.

I hope to discuss concrete schedules, possible changes to station placement, and ways to keep operating costs under control in a future post. For now all I’ll note is that the MBTA needs to stop pushing for extensions far out into suburbia. It’s not going to get ridership out of 9 roundtrips per weekday with a 5-hour service gap, which is what the T. F. Green Airport station gets. It’s going to get it out of reliable, frequent all-day service.