The Great Blizzard of 1888 blocked the rail line in Westport, between the Saugatuck and Green's Farms stations.

[5] The line was grade separated into a cut in Mount Vernon in 1893 as a result of multiple collisions between trains and horsecars.

[9] The replacement of the Housatonic River Railroad Bridge that year completed quadruple-tracking of the line from Woodlawn Junction to New Haven.

The MTA took over operations in 1983, and merged Conrail's former commuter rail lines in the New York area into Metro-North.

The MTA undertook to rebuild the railroad, upgrading signals, tracks, ties, roadbeds, and rolling stock.

The Columbus Avenue station in Mount Vernon was closed in the Penn Central era, due to its proximity to Mt.

[15][16] It was a major freight route for the New Haven to Queens, where it interchanged with the Long Island Rail Road and the Pennsylvania Railroad.

[19] Currently, a study is being undertaken to detail the costs and benefits of implementing more frequent service on the line.

[27] On September 25, 2013, a Con Edison failure required the use of diesel locomotives and bus service between Mount Vernon and Harrison for 12 days.

[28] New Haven Line mainline trains primarily use electric multiple unit (EMU) consists of Kawasaki M8 railcars.

All New Haven Line electric trains change over between third rail and overhead catenary between Mount Vernon East and Pelham[29] at normal track speed.

Both catenary and third rail overlap for a quarter-mile between Mount Vernon East and Pelham to facilitate this changeover.

[citation needed] When the line was first electrified in 1907, trains transitioned between third rail and overhead catenary at Woodlawn Heights,[29][31] approximately 2 miles (3.2 km) southwest of Pelham.

[33] The first game scheduled was on September 20, 2009, when the New York Jets hosted the New England Patriots, following a successful test of trains in non-revenue service on August 23.

The program was only offered for the early afternoon games so that the NJT equipment could be moved back in place for the Monday morning rush hour.

[38] Beginning April 14, 2019, passengers heading to and from Grand Central can also travel on New Haven Line trains.

[42] Amtrak pays Metro-North for the right to run its trains on the line using its electrical system and the resulting increase in maintenance needs.

[8] Until the 1980s, the New Haven Line had a decentralized signaling system, and each section of track was controlled by a separate switch tower.

Cosmopolitans can be easily spotted by their red stripe along the side, the presence of pantographs on the lead cars in each set, and a dynamic braking grid on the roof.

M2s operated in married pairs, differentiating them from their predecessor equipment of Pullman Standard and 4400-series washboard MU's (retired since the late 1970s and early 1980s).

Many M2s were reconditioned to extend their useful life beyond the expected 25 years, undergoing a Critical Systems Repair (CSR) program.

[82] On July 20, 2011, the Connecticut Department of Transportation announced the order of 25 unpowered M8 railcars, with options for up to 25 more, at a cost of US$93 million to replace the 48-car M6 fleet.

[87] As with the Harlem and Hudson Lines, diesel-powered trains are driven by Brookville BL20GH and dual-mode GE Genesis P32AC-DM locomotives, paired with Shoreliner coaches.

[90] The Devon Transfer station was re-activated in 2016 from April until October to accommodate additional repairs and catenary wire work.

The station would have had two island platforms, allowing for improved express service on the New Haven Line, increasing capacity.

[96] In connection with the planned redevelopment of the Gilbert & Bennett Wire Mill as a residential neighborhood, reopening a Georgetown station on the Danbury Branch has been approved, though not yet scheduled or funded.

[100] The Spring 2009 Update for the first time held out the possibility of extension all the way to Pittsfield, MA, the original route of the New Haven Berkshire Division.

The new signal system finally began operation in 2013, but extensive work was still ongoing in 2014 because of unresolved problems with the drop gates at grade crossings.

The study advanced a single option of full (both peak and off-peak) service to Penn on the New Haven and Hudson Lines.

[110] As of February 2009, Connecticut legislators were discussing service on an old New Haven passenger line that ceased passenger service decades prior known as the Highland Line, part of the original New England Railroad, also known as the Central New England Railway, both eventual subsidiaries of The New York, New Haven and Hartford Railroad.