UPDATED 1:46PM: To include additional details about the Springfield Line Connecticut River Bridge.

Senators worry projects like East-West rail could be stuck in low gear if annual funds are zeroed out. (WMP&I)

Democrats in the United States Senate, including Massachusetts’s own Elizabeth Warren, are raising the alarm about potential cuts a federal matching program for state rail corridors. Among the routes this could impact are the “Inland Corridor.” This is actually part of the route for East-West rail service between Boston and Springfield. The funds at issue are also part of bloc of funding for Northeast Corridor projects.

Warren was one of sixteen senators who signed a letter they addressed to Senate appropriators that Connecticut Senator Chris Murphy has spearheaded. The letter notes that the federal-state intercity passenger rail program has funds available from President Joe Biden’s infrastructure bill. However, these funds were to supplement existing infrastructure spending. Repairing the rail network and expanding service requires the annual appropriation, too.

The infrastructure bill’s “investment alone is not sufficient to fully address the nation’s rail state-of-good-repair backlog nor to fully improve and expand intercity passenger rail in a way that America deserves,” the senators aid.

The senators addressed the letter to Senator Appropriations Chair Patty Murray (D-WA) and Ranking Member Cindy Hyde-Smith (R-MS).

The Inland Corridor refers to connecting Boston to New Haven via Hartford, Springfield and Worcester. Early East-West rail service could actually begin as an extension of Amtrak New Haven-Springfield shuttle to Boston. Regardless, medium and longer-term plans call for more service from Boston to New York to go via Springfield. In addition to serving cities along the corridor, it would add some capacity to buy section within the BosWash megalopolis.

House Republican’s plan to zero out the federal-state matching program would not imperil the $181 million the commonwealth has already received for East-West rial. However, an end to the program could have consequences both to East-West rail and service in Western Massachusetts generally.

Warren has been a vocal advocate of East-West rail. (WMP&I)

Another Massachusetts route that could see an impact, the letter states, is the Downeaster, which connects coastal Maine to New Hampshire and Boston.

Neither Murphy nor Warren’s offices responded to a request for comment about additional impacts. The existing Springfield line itself, on which Amtrak runs its shuttles and the Connecticut Department of Transportation runs commuter service, is a branch of the Northeast Corridor. It feeds into the rest of the corridor via New Haven.

The system already suffers from ancient infrastructure, some of which dates to the presidency of Ulysses Grant. The sections of the mainline Northeast Corridor in need of repair that affect the 413 most directly are south of New Haven. These include century-old bridges on the route to New York. However, the Springfield line also needs significant upgrades. Most prominent among them is the replacement of the Connecticut River Bridge between Enfield and Windsor Locks.

This bridge, which was rebuilt in its current form 120 years ago, has speed restrictions. It was reduced to a single track some decades ago. A November report from the Northeast Corridor Commission states, “The current bridge significantly slows both Commuter and Intercity trains as well as creates a capacity bottleneck impacting” on-time performance.

This bridge did not receive a grant last year. Given backlogs, other projects had higher priority. However, the program senators wrote about is likely a source for funding for the bridge.

Ending the program’s annual appropriation could also put a drag on expanding service west to Springfield to Albany. The funding Massachusetts received for East-West rail concerns some upgrades to expand capacity. However, it will have no immediate impact on rest of old Boston & Albany route to Pittsfield and into the New York Capital Region.