THE SOUTH STATION expansion plan once again is rearing its costly, business-as-usual head. The possible relocation of the Dorchester Avenue Postal Service facility presents an opportunity to drastically improve walkability, add mixed-use development, and enhance climate resilience in downtown Boston. Using much of that land to expand the number of tracks at South Station would make such a transformation far harder and come at significant public expense at a time when we should be strategically spending our limited financial resources.

In 2020 dollars, the most recent cost estimate for the expansion sat at $2.5 billion; even at high-end cost, this sum could complete the first phase of rail electrification (covering the Providence/Stoughton, Fairmount, and Newburyport/Rockport lines) and electrifying the Framingham/Worcester Line. But the Commonwealth has made no progress on modernizing the existing antiquated commuter rail system into the more reliable, more frequent, and more useful regional rail system that the MBTA committed to in 2019.

The MBTA has long argued that South Station expansion is the only way to increase frequency on the southern side of the commuter rail system. But several rail terminals accommodate more trains than South Station did as of 2019 with fewer tracks and platforms – because they operate according to a version of the operating philosophy often called “organization before electronics before concrete” and maximize the value of existing infrastructure with reliable trains and modern operating practices.

Given this real-world experience, we believe North and South stations can accommodate as much as a 50 percent increase in train throughput relative to pre-COVID peak levels, accounting for realistic Amtrak frequency increases, if it transforms the rail system into true regional rail, starting with Phase 1 of rail transformation.

South Station contains 13 platform tracks, two of which are reserved for Amtrak, and six approach, or throat, tracks. Under a maximum build of regional rail as proposed by TransitMatters, 20 peak trains per hour would operate on the Framingham/Worcester, Providence/Stoughton, and Franklin lines combined. The single track on the Old Colony Main Line limits its frequency to six trains per hour total, or two for each branch. More frequent service on the Fairmount Line adds eight more trains.

That leaves us with 11 tracks to manage 34 MBTA trains, or an average of three trains per platform per hour or nearly 20 minutes per train. Many systems throughout the world, including several in the United States, regularly turn their trains around at large terminal stations in under 15 minutes, and in many cases as little as five minutes, often on fewer platform and throat tracks than what South Station has. Many systems can achieve these turnaround times; the MBTA routinely turns trains in 10 minutes at outlying terminals like Worcester.

Amtrak trains should not be an impediment to our plan. On average, each Amtrak train can discharge and load passengers over a 40-minute time period (20 minutes on each end), with functions like cleaning and restocking performed off platform in Amtrak’s yard. Amtrak currently operates a maximum of two trains per hour into South Station. Additional Northeast Corridor frequency is constrained by drawbridges in southeastern Connecticut; plans to replace or bypass them exist but are currently unfunded and don’t even have a Bipartisan Infrastructure Legislation funding request. Hourly East-West Rail service, either as a Worcester Line express train or Amtrak service from New Haven and Hartford, will add a third intercity train per hour.

In the future, with the above constraints resolved, there may be four intercity trains per hour from the Northeast Corridor. In that case, they can still fit two platforms if they go in and out in less than 30 minutes, which is judged a limiting but possible arrangement in the California High-Speed Rail planning documents for the much more constrained Transbay Terminal in San Francisco.

With well-maintained new trains, better crew staging, and improvements to switches and tracks, South Station should be able to comfortably accommodate the increased frequency on its existing footprint. Modern electric multiple unit trains (EMUs) are drastically more reliable than the equipment the MBTA runs today – the least reliable EMUs are five times more reliable than the most reliable diesel locomotives in the MBTA’s fleet – drastically reducing the frequency of equipment failures. Failures will become infrequent enough to the point that when flexibility between platforms is needed, it will represent a comparatively minor inconvenience. In short, it would be a bad investment to spend several billion dollars to expand South Station in part to accommodate our antiquated, slow, diesel locomotive fleet.  That is no way to make such significant spending decisions, decisions that will crowd out many other worthy initiatives.

We have a limited number of years to save our planet. Let’s not waste them perpetuating outdated operating models. The commuter rail network spans most of Eastern and Central Massachusetts, serving its largest and fastest growing cities. It’s also core to a vision of statewide rail travel. By improving the reliability, potential frequency, and speed of commuter rail, electrification enables ridership, reducing vehicle miles traveled, and aiding immensely in meeting the Commonwealth’s 2050 zero net carbon emissions goal. A parked train doesn’t provide any benefit. The regional rail concept is one of frequent, reliable service, not frequent parking.

Building the rail network metro Boston needs to meet today’s and tomorrow’s needs won’t happen as long as the T focuses on status quo operations at tremendous expense over spending that money on modernizing the system. Investing in our electric future, not our diesel past, is the way to go. Let’s be leaders. We owe it to our children.

Jay Flynn is the TransitMatters East-West Rail campaign coordinator.